Instituto IMDEA Nanociencia C/ Faraday, 9 Spain · 1. Femtosecond laser induced periodic surface...

6th-8th

novInstituto IMDEA NanocienciaC/ Faraday, 928049 Madrid Spain

Ultrafast Science and TechnologySPAIN

Sponsored by:Promoted by:

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Ultrafast Science and Technology

SPAIN

6th-8th

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Scientific Committee

Luis Bañares Univ. Complutense de Madrid

Crina Cojocaru Univ. Politècnica de Catalunya

Jesús González Vázquez Univ. Autónoma de Madrid

Fernando Martín UAM & IMDEA Nanociencia

Alicia Palacios Univ. Autónoma de Madrid

Luis Roso Univ. de Salamanca

Organizing Committee

Chair: F. Martín UAM & IMDEA Nanociencia

Cristina Díaz Univ. Autónoma de Madrid

Beatriz Martín Univ. Autónoma de Madrid

Alicia Palacios Univ. Autónoma de Madrid

Antonio Picón Univ. Autónoma de Madrid

Ignacio Torres IMDEA Nanociencia


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Welcome to USTS 2019 Welcome to the third edition of the Ultrafast Science and Technology Spain meeting (USTS 2019) celebrated in IMDEA-Nanoscience, Madrid, from 6th to 8th November, 2019.

USTS 2019 has been promoted by the Grupo Especializado de Láseres Ultrarrápidos (GELUR) of the RSEF and the Madrid Region in the frame of FULMATEN-CM (Y2018/NMT-5028). The main objective of this event is to continue a series of Meetings aimed at gathering and promoting the whole Ultrafast Laser Community in Spain, providing a space for encounter, discussion and dissemination of the most recent results in Ultrafast Science, and facilitating synergies among groups with common themes, tools or methodologies. Senior, post-doctoral researchers and PhD and Master students are very welcome.

The scope of USTS 2019 is broad and multidisciplinary, covering different topics such as ultrafast laser development, femtosecond laser spectroscopy and microscopy, nonlinear optical phenomena, attosecond physics, ultrafast synchrotron and XFEL studies, and in general any ultrafast study related to biology, chemistry and condensed matter.

USTS2019 is sponsored by:

USTS 2019 has been promoted by the Grupo Especializado de Láseres Ultrarrápidos (GELUR) of the RSEF and the Madrid Region in the frame of FULMATEN-CM (Y2018/NMT-5028).

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The conference venue is the IMDEA Nanoscience Institute (C/ Faraday, 9 · Campus de Cantoblanco, 28049 Madrid · Spain).

The lectures will take place in the Conference Room of IMDEA Nanociencia.

Coffee breaks will be served in Nanociencia’s hall, in the same place than the Conference Room.

Poster session will take place in Nanociencia’s hall on Wednesday and Thursday at 18:00 h. Please, check this booklet for your presentation day. You can hang your poster any time during the day.

WiFi is available in the campus: 1) access to internet connecting to the eduroam wireless network, 2) an open WiFi network available at IMDEA Nanociencia.

Lunches are included in your registration fee. Tickets are only valid at Cafeteria at Plaza Mayor.

Thursday afternoon, at 19:30 h, all registered participants are invited for Tapas. Tapas event will take place in the Cafeteria of IMDEA Nanoscience.

We hope you enjoy the workshop!

ResidenciaUniversitariaErasmo

ConsejoSuperior deInvestigacionesEstación

CantoblancoUniversidad

M-616

M-616M-607

M-616

M-607

M-607M-607

ResidenciaUniversitariaErasmo

C/ Faraday, 928049 Madrid

EstaciónCantoblancoUniversidad

Plaza Mayor UAM

Universidad Autónoma de MadridCampus Cantoblanco

Calle Francisco Tom

ás y Valiente

Calle de Marie Curie

Calle de Marie Curie

Calle

Farad

ay

Calle Faraday

Calle Faraday

Calle Nicolás Cabrera Calle Nicolás Cabrera

Practical information

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Program Wednesday 6th11:00 CONFERENCE OPENING Local Organizing Committee, IMDEA and GELUR

Representatives

Sesion 1 Chair: Fernando Martín Univ. Autónoma de Madrid

11:10 URSULA KELLER ETH ZURICH Attosecond electron dynamics driven by optical

fields: moving from atoms to condensed matter11:55 FERNANDO ARDANA-LAMAS ETH ZURICH Attosecond transient absorption on CH4, C2H6

and C2H4 in the water-window12:25 LARRY LÜER IMDEA NANOCIENCIA Ultrafast Spectroscopy of Organic Materials for

Energy Applications

12:55 LUNCH

Sesion 2Chair: Antonio Picón Univ. Autónoma de Madrid

15:00 JENS BIEGERT ICFO Measuring Electronic and Lattice with

Attosecond X-ray Absorption spectroscopy15:30 CRUZ MÉNDEZ CLPU VEGA laser facility: characterization and

beamlines management16:00 REBECA DE NALDA IQFR-CSIC Mapping nonadiabatic molecular dynamics

with time-resolved Coulomb explosion images

16:30 COFFE BREAK

Sesion 3 Chair: Rosa María Weignad Univ. Complutense de Madrid

17:00 ABDERRAZZAK DOUHAL UCLM Witnessing the ultrafast dynamics within

Ce-based MOFs: relevance to photonics and photocatalysis

17:20 MARTA L. MURILLO-SÁNCHEZ UCM Structural dynamics effects on the UV electronic

predissociation of alkyl iodides at 201 nm17:40 MANUEL MACÍAS-MONTERO MONTERO IO-CSIC Migration and refractive index control in

phosphate glasses by femtosecond laser induced element redistribution

18:00 POSTER SESSION Author list in page 8

18:00 GELUR GENERAL ASSEMBLY

Thursday 7th

Sesion 4Chair: Luis Bañares Univ. Complutense de Madrid

9:00 FRANCK LÉPINE UNIV. LYON XUV induced dynamics in large polyatomic

systems: Ultrafast charge and energy flow9:45 ROSARIO GONZÁLEZ-FÉREZ UNIV. GRANADA Rotational dynamics of complex molecules in

external fields10:15 KLAVS HANSEN TIANJIN UNIV. Single photon hot eletron ionization of fullerenes

10:45 COFFEE BREAK

Sesion 5Chair: Iñigo Solá Universidad de Salamanca

11:15 CARLOS HERNÁNDEZ-GARCÍA UNIV. SALAMANCA Accelerated twist at the ultrafast: the self-

torque of light

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nov11:45 ETIENNE PLÉSIAT UNIV. AUTÓNOMA DE MADRID Real-Time Imaging of Ultrafast Charge

Dynamics in CF4 from Attosecond Pump-Probe Photoelectron Spectroscopy

12:15 EMILIO PISANTY PISANTY ICFO Conservation of Torus-Knot Angular Momentum

in High-Harmonic Generation Driven by Fields with Spin-Orbit Mixing

12:35 ÁLVARO JIMÉNEZ-GALÁN MBI Topological strong field physics on sub-laser

cycle timescale

12:55 LUNCH

Sesion 6Chair: Javier Solís CSIC

15:00 DOLORES MARTÍN UNIV. AUTÓNOMA DE MADRID Ultrafast interference dynamics of polariton

condensates15:30 JOHANNES FEIST UNIV. AUTÓNOMA DE MADRID Ultrafast coupled photonic, electronic, and

nuclear dynamics in molecular polaritons16:00 ASIER LONGARTE UPV/EHU Lifetimes, Photostability and other Photophysical

Aspects of Life-Related Molecules

16:30 COFFEE BREAK

Sesion 7 Chair: Crina Cojocaru CSIC

17:00 CHRISTOPHER ARRELL SWISSFEL Temporal jitter stabilisation of SwissFEL17:20 LAURA CATTANEO ETHZ Photoionization dynamics in simple molecules:

the case of H2, CO and N2O17:40 JOSE A. PÉREZ-HERNÁNDEZ CLPU Generation of high energy laser-driven electron

and proton sources with the 200 TW system VEGA 2 at the Centro de Láseres Pulsados

18:00 POSTER SESSION Author list in page 10

19:30 SOCIAL PROGRAM: TAPAS

Friday 8th

Sesion 8 Chair: Luis Roso Univ. Salamanca & CLPU

9:00 MAURO NISOLI POLITECNICO DI MILANO Attosecond molecular physics: investigation

and control of ultrafast processes in bio-relevant molecules

9:45 MARÍA TERESA FLORES UNIV. SANTIAGO DE COMPOSTELA

Evaluation of the tolerance on solid nanostructured targets for proton laser acceleration

10:15 ELISABET ROMERO ICIQ TBA

10:45 COFFEE BREAK

Sesion 9 Chair: Alicia Palacios Univ. Autónoma de Madrid

11:15 WOJCIECH GAWELDA EUROPEAN XFEL Bright Future for X-ray Science: European XFEL11:45 DOOSHAYE MOONSHIRAM IMDEA NANOCIENCIA Tracking the electronic and structural

configurations of earth-abundant photosensitizers and water splitting catalysts for artificial photosynthesis

12:15 BEATA ZIAJA-MOTYKA MOTYKA CFEL Transitions in X-ray irradiated solid materials12:35 DANIEL RIVAS RIVAS EUROPEAN XFEL Ultrafast soft x-ray spectroscopy at the

European XFEL

12:55 LUNCH

15:00 FAREWELL

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Poster Session

Wednesday 6th1. Femtosecond laser induced periodic surface structures as substrate patterns for the growth of Zr-doped ZnO

structures. Rocío Ariza, Belén Sotillo, Ana Urbieta, Jan Siegel, Javier Solís, and Paloma Fernández, Complutense

University of Madrid

2. Electron angular distribution in double ionization of H2. Kilian Arteaga, Johannes Feist, Fernando Martín, and Alicia

Palacios, Universidad Autónoma de Madrid

3. Deepening into the nucleation and fission processes of nano-hydrated ammonia clusters - a combined theoretical and experimental study. D. Barreiro, B. Oostenrijk, N. Walsh , A. Sankari, E. P. Mansson, S. Maclot, S. Sorensen, S.

Díaz-Tendero, and M. Gisselbrecht, Universidad Autónoma de Madrid

4. Ultrafast Fiber Lasers for High-Resolution MultiPhoton Microscopy. Pascal Dupriez and Victor Blanco, Spark Lasers

5. Using Broadband Time-Resolved THz Spectroscopy in the Study of Hot Carrier Dynamics in Lead, Halide

Perovskites, Andrés Burgos-Caminal, Juan Manuel Moreno-Naranjo, Aurélien René Willauer, Arun Abi Paraecattil,

Ahmad Ajdarzadeh and Jacques-E. Moser, École Polytechnique Fédérale de Lausanne

6. Differences in the Photobehavior of Two Chemically Identical but Structurally Distinct MOFs. Elena Caballero-Mancebo, Boyko Cohem, Simon Smolders, Dirk de Vois, and Abderrazzak Douhal, Universidad de Castilla-La Mancha

7. On the problem of achieving low-threshold yellow-green polymer lasing in energy transfer blends. Juan Cabanillas-González, Qi Zhang, Chen Sun, Larry Lüer, Jingguang Liu, Xiangru Guo, Qi Wei, Ruidong Xia, Yan Qian,

Donal D C Bradley, and Wei Huang, IMDEA Nanociencia

8. Laser-induced periodic surface structures on germanium by femtosecond irradiations. Noemí Casquero, Yasser

Fuentes-Edfuf, Javier Solís, and Jan Siegel, Instituto de Óptica (IO-CSIC)

9. The Influence of β-Phase Conformation on Transient Absorption and Light Amplifying Properties of Polydiarylfluorene. Chen Sun, Jinyi Lin, Jaime J. Hernández Rueda, Xingyuan Shi, Aleksandr Perevedentsev, and

Juan Cabanillas-Gonzalez, IMDEA Nanociencia

10. High harmonic generation assisted by single excited multielectron states. Alba de las Heras, Luis Plaja and

Carlos Hernández-García, University of Salamanca

11. Attosecond spectroscopy of small organic molecules. Jorge Delgado, A. Palacios, M. Lara-Astiaso, J. González-

Vázquez, P. Decleva, and F. Martín, Universidad Autónoma de Madrid

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nov12. Polarization Effects on Laser-Driven Electronic Transfer Processes. Francisco Fernández-Villoria, Antonio Garzón-

Ramírez, and Ignacio Franco, Universidad Autónoma de Madrid

13. Ionization from a coherent superposition in CCl2F2. Pedro Fernández-Milán, Markus Klinker, Jesús González-

Vázquez, and Fernando Martín, Universidad Autónoma de Madrid

14. Time delays from one-photon transistions in the continuum. Jaco Fuchs, Nicolas Douguet, Stefan Donsa, Fernando

Martin, Joachim Burgdörfer, Luca Argenti, Laura Cattaneo, and Ursula Keller, ETH Zürich

15. The role of surface roughness in the formation of LIPSS on metals. Yasser Fuentes-Edfuf, José A. Sánchez-Gil,

Marina Garcia-Pardo, Rosalia Serna, Vincenzo Giannini, Javier Solis, and Jan Siegel, Instituto de Óptica (IO-CSIC)

16. Signatures of matter Talbot effect in the high-order harmonic generation from periodic systems. Ana García-Cabrera, Carlos Hernández-García, and Luis Plaja, University of Salamanca

17. Deciphering the ultrafast events in a new HOF with remarakable responssiveness to acids. Eduardo Gomez, Yuto

Suzuki, Ichiro Hisaki, and Abderrazzak Douhal, Universidad de Castilla-La Mancha

18. THz spectroscopic imaging at kHz pixel rates. Albrecht Bartels and Matthias Beck, Laser Quantum GmbH

19. Commissioning of the pump-probe laser infrastructure of the Small Quantum System instrument at the European XFEL. Thomas Baumann, Rebecca Boll, Alberto De Fanis, Patrik Grychtol, Markus Ilchen, Jia Liu, Tommaso Mazza,

Jacobo Montaño, Valerija Music, Yevheniy Ovcharenko, Nils Rennhack, Daniel E Rivas, Philipp Schmidt, Sergey Usenko,

René Wagner, Paweł Ziolkowski, Jan Grünert, and Michael Meyer, European XFEL

20. Excited state dynamics of pyrrole-containing clusters. Iker Lamas, Raúl Montero, and Asier Longarte, University

of the Basque Country

21. Ultrafast x-ray scattering from molecular wavepackets. Andrés Moreno Carrascosa, Mats Simmermacher, and

Adam Kirrander, Brown University

22. Time-resolved photodissociation dynamics of vinyl iodide in the UV at 199.2 and 200. M. L. Murillo-Sánchez, I. Mondejar and L. Bañares, Universidad Complutense de Madrid

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Thursday 7th1. Femtosecond XUV-IR dynamics of the methyl iodide cation. M. L. Murillo-Sánchez, G. Reitsma, R. de Nalda, M.

E. Corrales, S. Marggi Poullain, J. Gonzalez-Vázquez, M. J. J. Vrakking, L. Bañares, and O. Kornilov, Universidad

Complutense de Madrid

2. Time-resolved two-color X-ray spectroscopy: A site-selective probe of the ultrafast dynamics of core-excited molecules. S. Oberli, J. González-Vázquez, E. Rodríguez-Perelló, M. Sodupe, F. Martín, and A. Picón, Universidad

Autónoma de Madrid

3. Hydrodynamic and Maxwell-Bloch simulation of plasma-based UV, XUV and soft X-ray lasers. Eduardo Oliva, Universidad Politécnica de Madrid

4. 4. Ultrafast Light-induced nucleation of magnetic skyrmions in Pt/Co/Pt magnetic trilayers. Pablo Olleros-Rodríguez, Mara Strungaru, Sergiu Ruta, Roy W. Chantrell, Oksana Chubykalo-Fesenko, and Paolo Perna, IMDEA

Nanociencia

5. Effects of core and active space on attosecond dynamics. Juan J. Omiste and Lars B. Madsen, IMDEA Nanociencia

6. Ultrafast Laser Facilities for Microscopy and Spectroscopy at the University of Málaga. J. C. Otero, C. Ruano,

and J. Román-Pérez, University of Málaga

7. How to measure sub-7 fs laser pulses using clusters of second-harmonic nanoparticles: nano-dispersion-scan. Óscar Pérez-Benito and Rosa Weigand, University Complutense

8. Time-resolved X-ray spectroscopy for periodic complex systems. G. Cistaro, F. Martín, and Antonio Picón, Universidad Autónoma de Madrid

9. Site-depending tunnel-ionization in molecular high-harmonic spectroscopy. Laura Rego, Carlos Hernández-García,

Antonio Picón and Luis Plaja, University of Salamanca

10. Characterization of the conductivity, mobility and carrier density in semiconductors via time resolved THz spectroscopy. Sergio Revuelta and Enrique Cánovas, IMDEA Nanociencia

11. Femtosecond laser drilling of metals with axicon lens and filamentation. Mauricio Rico, Camilo Florian, Mariano

Jubera, and Luis Roso, Centro de Láseres Pulsados, Parque Científico

12. LASERONUAV – Development of a laser microdiode in 2.1um as countermeasure system from RPAs. Mauricio Rico, Benjamín Colomer, Rafael Ortiz, and Luis Roso, Centro de Láseres Pulsados, Parque Científico

13. Surface and bulk harmonic generation in the opaque region of GaAs: experiment versus theory. L. Rodriguez-

Suné, J. Trull, M. Scalora, and C. Cojocaru, Universitat Politècnica de Catalunya

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SPAIN

6th-8th

nov14. FXE a Sprectroscopy and Scattering instrument at the European XFEL facility. Angel Rodriguez-Fernandez,

Wojciech Gawelda, Mykola Biednov, Andreas Galler, Katharina Kubicek, Dmitry Khakhulin, Frederico Alves Lima, Peter

Zalden, and Christian Bressler, European XFEL

15. Phase contrast tomography with a stable, ultrashort, microfocus laser driven plasma X-Ray source. L. Martín, J.

Benlliure, D. Cortina, D. González, J. Llerena, J. Peñas, and C. Ruíz, IGFAE, Universidade de Santiago de Compostela

16. A high repetition, stable, laser driven plasma proton source for medical isotope production. L. Martín, J. Benlliure,

D. Cortina, D. González, J.J. Llerena, J. Peñas, C. Ruíz, M. Seimetz, IGFAE, Universidade de Santiago de Compostela

17. Safe limits for the application of nonlinear optical microscopies to cultural heritage: a new method for in-situ assessment. M. Sanz, M. Oujja, A. Dal Fovo, S. Mattana, M. Marchetti, R. Cicchi, F. Pavone, R. Fontana, and M.

Castillejo, Instituto de Química Física Rocasolano

18. Photoexcitation Dynamics of Solution-processable All-small-molecule Bulk Heterojunction Photovoltaic Blends. Junqing Shi, Anna Isakova, Abasi Abudulimu, Marius van den Berg, Oh Kyu Kwon, Alfred J. Meixner, Soo Young Park,

Dai Zhang, Johannes Gierschner, and Larry Lüer, IMDEA Nanociencia

19. Polaritonic Molecular Clock: All-Optical Ultrafast Imaging of Wavepacket Dynamics withou Probe Pulses. R. E. F. Silva, Javier del Pino, Francisco J. García-Vidal, and Johannes Feist, Universidad Autónoma de Madrid

20. High stability retrieval of vector pulses. Iñigo J. Sola and Benjamín Alonso, University of Salamanca

21. Ultrafast non-linear absorption excitation of Tb,Eu-based nanothermometers. Carlos Zaldo, Mauricio Rico, María

Dolores Serrano, and Concepción Cascales, Instituto de Ciencia de Materiales de Madrid, CSIC

22. Formation of excimer laser-induced periodic surface structures on silicon at angled incidence. Raúl Zazo, Javier

Solís, and Jan Siegel, Instituto de Óptica, CSIC

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Plenary SpeakersUrsula Keller ETH ZurichFrank Lépine LASIM, LyonMauro Nisoli Politecnico de Milano

Invited SpeakersFernando Ardana-Lamas ETHZJens Biegert ICFOJohannes Feist Universidad Autónoma de MadridMaría Teresa Flores Universidad de Santiago de CompostelaWojciech Gawelda European XFELRosario González Universidad de GranadaKlavs Hansen Tianjin UniversityCarlos Hernández-García Universidad de SalamancaAsier Longarte Universidad del País VascoLarry Lüer IMDEA NanocienciaDolores Martín Universidad Autónoma de MadridCruz Méndez Centro de Láseres PulsadosDooshaye Moonshiram IMDEA NanocienciaRebeca de Nalda IQFR-CSICEtienne Plésiat Universidad Autónoma de MadridElisabet Romero ICIQ

Oral SpeakersAbderrazzak Douhal UCLMMarta L. Murillo-Sánchez UCMManuel Macías-Montero CSICEmilio Pisanty ICFOÁlvaro Jiménez-Galán MBIChristopher Arrel SwissFELLaura Cattaneo ETHZJosé A. Pérez-Hernández CLPUBeata Ziaja-Motyka CFELDaniel Rivas European XFEL

Abstracts

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PLENARY Attosecond electron dynamics driven by optical fields: moving

from atoms to condensed matter L. Gallmann1, M. Lucchini1,2, F. Schläpfer1, M. Volkov1, S. A. Sato4,5, L. Kasmi1, N. Hartmann1,

A. Ludwig1, J. Herrmann1, Y. Shinohara3, K. Yabana4, A. Rubio5, U. Keller1

1Physics Department, ETH Zurich, Zurich, Switzerland 2Department of Physics, Politecnico di Milano, Milano, Italy 3Photon Science Center, University of Tokyo, Tokyo, Japan

4Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan 5Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

E-mail: [email protected]

With the recent progress in few-optical-cycle femtosecond and attosecond pulse generation with full electric field control [1] we can measure attosecond electron dynamics. Based on different theoretical approximations and experimental techniques we have made significant progress in our understanding of attosecond ionization dynamics from atoms, molecules and surfaces. In addition terahertz spectroscopy can be scaled towards petahertz with electric-field-driven electron dynamics in condensed matter targets such as diamond, GaAs and Ti.

We will first present a short overview of what we have learned with atoms and then move towards our recent work on attosecond electron dynamics in bulk solids. For these studies, thin films of a large-bandgap dielectric (diamond), a semiconductor (GaAs), and metals (Ti and Zr) were exposed to near-infrared (NIR) optical fields at intensities on the order of 1011 W/cm2 to several times 1012 W/cm2. The electronic response during the interaction with the ultrashort optical pulse was then tracked with attosecond transient absorption spectroscopy (ATAS).

In the 1980s, rapid progress in picosecond and femtosecond ultrafast lasers has enabled to start to bridge the gap between electronics and optics with the optical generation of terahertz frequencies for the investigation of ever faster physical processes and device performance. More recently with full electric field control within few-cycle pulses [1] we have continued to fully bridge this gap approaching the petahertz regime. A number of pioneering publications demonstrated that attosecond carrier transport can be resolved with attosecond transient absorption spectroscopy (ATAS) [2-5] and an attosecond interferometry technique at solid surfaces using time- and angle-resolved photoemission spectroscopy (tr-ARPES) [6,7]. After a general introduction we will discuss in more details some recent results from our group in diamond [5], GaAs [8,9] and Ti-metal [10]. In addition I will discuss the effective mass approximation in the attosecond regime on a Cu surface [11].

In diamond several NIR photons are needed to bridge the band gap. We find that the transient optical response high above the band gap is dominated by intra-band electron motion and can be explained by the dynamical Franz-Keldysh effect [5]. In GaAs, on the other hand, transitions from the valence to the conduction band are driven resonantly by the 800 nm wavelength pump. However, rather counterintuitively, we find that the transient response is still dominated by intra-band dynamics [8]. While by definition only inter-band transitions lead to the excitation of real carriers into the conduction band, the interplay of inter-band with intra-band processes enhances the carrier injection by a factor of 3 compared to a case that considers inter-band transitions only [9]. In the transition metals Ti and Zr we find that the NIR pulse drives the localization of the electronic density on the d-orbitals. The associated rapid change in screening can be observed thanks to the attosecond resolution of our experiment that yields insights into the brief time window before the fast electronic thermalization in these materials kicks in. Localization of valence electrons is expected to modify macroscopic properties of transition metals [10].

Notes and References [1] H. R. Telle et al., "Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and

ultrashort pulse generation," Appl. Phys. B 69, 327 (1999) [2] M. Schultze et al., "Attosecond band-gap dynamics in silicon " Science 346, 1348 (2014) [3] H. Mashiko, et al., "Petahertz optical drive with wide-bandgap semiconductor," Nature Physics 12, 741 (2016) [4] M. Schultze et al., "Controlling dielectrics with the electric field of light," Nature 493, 75 (2013) [5] M. Lucchini et al., "Attosecond dynamical Franz-Keldysh effect in polycrystalline diamond," Science 353, 916 (2016) [6] R. Locher et al., “Energy-dependent photoemission delays from noble metal surfaces by attosecond interferometry” Optica 2, 405

(2015) [7] M. Lucchini et al., “Light-matter interaction at surfaces in the spatiotemporal limit of macroscopic models”, Phys. Rev. Lett. 115,

137401 (2015) [8] F. Schlaepfer et al., Equation Chapter 1 Section 1“Attosecond optical-field-enhanced carrier injection into the GaAs conduction

band”, Nature Physics 14, 560 (2018) [9] S. A. Sato et al., “Role of intraband transitions in photocarrier generation”, Phys. Rev. B 98, 035202 (2018) [10] M. Volkov, S. A. Sato, F. Schlaepfer, L. Kasmi, N. Hartmann, M. Lucchini, L. Gallmann, A. Rubio, U. Keller, Nature Physics,

published online 5. Aug. 2019 [11] L. Kasmi et al., “Effective mass effect in attosecond electron transport”, Optica 4, 1492 (2017)

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PLENARY Attosecond electron dynamics driven by optical fields: moving

from atoms to condensed matter L. Gallmann1, M. Lucchini1,2, F. Schläpfer1, M. Volkov1, S. A. Sato4,5, L. Kasmi1, N. Hartmann1,

A. Ludwig1, J. Herrmann1, Y. Shinohara3, K. Yabana4, A. Rubio5, U. Keller1

1Physics Department, ETH Zurich, Zurich, Switzerland 2Department of Physics, Politecnico di Milano, Milano, Italy 3Photon Science Center, University of Tokyo, Tokyo, Japan

4Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan 5Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany


With the recent progress in few-optical-cycle femtosecond and attosecond pulse generation with full electric field control [1] we can measure attosecond electron dynamics. Based on different theoretical approximations and experimental techniques we have made significant progress in our understanding of attosecond ionization dynamics from atoms, molecules and surfaces. In addition terahertz spectroscopy can be scaled towards petahertz with electric-field-driven electron dynamics in condensed matter targets such as diamond, GaAs and Ti.

We will first present a short overview of what we have learned with atoms and then move towards our recent work on attosecond electron dynamics in bulk solids. For these studies, thin films of a large-bandgap dielectric (diamond), a semiconductor (GaAs), and metals (Ti and Zr) were exposed to near-infrared (NIR) optical fields at intensities on the order of 1011 W/cm2 to several times 1012 W/cm2. The electronic response during the interaction with the ultrashort optical pulse was then tracked with attosecond transient absorption spectroscopy (ATAS).

In the 1980s, rapid progress in picosecond and femtosecond ultrafast lasers has enabled to start to bridge the gap between electronics and optics with the optical generation of terahertz frequencies for the investigation of ever faster physical processes and device performance. More recently with full electric field control within few-cycle pulses [1] we have continued to fully bridge this gap approaching the petahertz regime. A number of pioneering publications demonstrated that attosecond carrier transport can be resolved with attosecond transient absorption spectroscopy (ATAS) [2-5] and an attosecond interferometry technique at solid surfaces using time- and angle-resolved photoemission spectroscopy (tr-ARPES) [6,7]. After a general introduction we will discuss in more details some recent results from our group in diamond [5], GaAs [8,9] and Ti-metal [10]. In addition I will discuss the effective mass approximation in the attosecond regime on a Cu surface [11].

In diamond several NIR photons are needed to bridge the band gap. We find that the transient optical response high above the band gap is dominated by intra-band electron motion and can be explained by the dynamical Franz-Keldysh effect [5]. In GaAs, on the other hand, transitions from the valence to the conduction band are driven resonantly by the 800 nm wavelength pump. However, rather counterintuitively, we find that the transient response is still dominated by intra-band dynamics [8]. While by definition only inter-band transitions lead to the excitation of real carriers into the conduction band, the interplay of inter-band with intra-band processes enhances the carrier injection by a factor of 3 compared to a case that considers inter-band transitions only [9]. In the transition metals Ti and Zr we find that the NIR pulse drives the localization of the electronic density on the d-orbitals. The associated rapid change in screening can be observed thanks to the attosecond resolution of our experiment that yields insights into the brief time window before the fast electronic thermalization in these materials kicks in. Localization of valence electrons is expected to modify macroscopic properties of transition metals [10].

Notes and References [1] H. R. Telle et al., "Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and

ultrashort pulse generation," Appl. Phys. B 69, 327 (1999) [2] M. Schultze et al., "Attosecond band-gap dynamics in silicon " Science 346, 1348 (2014) [3] H. Mashiko, et al., "Petahertz optical drive with wide-bandgap semiconductor," Nature Physics 12, 741 (2016) [4] M. Schultze et al., "Controlling dielectrics with the electric field of light," Nature 493, 75 (2013) [5] M. Lucchini et al., "Attosecond dynamical Franz-Keldysh effect in polycrystalline diamond," Science 353, 916 (2016) [6] R. Locher et al., “Energy-dependent photoemission delays from noble metal surfaces by attosecond interferometry” Optica 2, 405

(2015) [7] M. Lucchini et al., “Light-matter interaction at surfaces in the spatiotemporal limit of macroscopic models”, Phys. Rev. Lett. 115,

137401 (2015) [8] F. Schlaepfer et al., Equation Chapter 1 Section 1“Attosecond optical-field-enhanced carrier injection into the GaAs conduction

band”, Nature Physics 14, 560 (2018) [9] S. A. Sato et al., “Role of intraband transitions in photocarrier generation”, Phys. Rev. B 98, 035202 (2018) [10] M. Volkov, S. A. Sato, F. Schlaepfer, L. Kasmi, N. Hartmann, M. Lucchini, L. Gallmann, A. Rubio, U. Keller, Nature Physics,

published online 5. Aug. 2019 [11] L. Kasmi et al., “Effective mass effect in attosecond electron transport”, Optica 4, 1492 (2017)

INVITED Attosecond transient absorption on CH4, C2H6 and C2H4 in the

water-window Fernando Ardana-Lamas*a, Kristina Zinchenkoa and Hans-Jakob Woernera

aLaboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland E-mail: [email protected]

We present a study on the ultrafast molecular dynamics for different hydrocarbons. The molecular dynamics under the effect of a strong near-infrared (NIR) laser field is resolved using attosecond transient absorption spectroscopy1 (ATAS) on the carbon K-edge. With this technique, we have been able to observe the differences in the dynamics for three basic hydrocarbons: methane, ethane, and ethylene with a temporal resolution below 100 as2.

The experimental setup, consists of Ti:Sa laser system pumping an optical parameter amplifier (OPA). The OPA is tune to generate a 1.8 um, 30 fs pulses laser pulses. The output of OPA is spectrally broadened in an argon filled hollow-core fiber allowing to obtain pulses with an energy of up to 1.8 mJ and pulse duration below 10 fs. The output of the fiber is split using a broadband beam splitter. Around 1 mJ is used to drive the high-harmonic generation (HHG) process obtaining a soft X-ray (SXR) spectrum that covers from the sulfur L-edge up to the nitrogen K-edge. The reaming energy, 800 uJ, is used to pump the sample. The gas sample is delivered using a pulse valve with opening times down to 30 us. The spectrum is recorded using a flat field diffraction grating in combination with an X-ray CCD camera.

The change in the transient optical density ΔOD of ethylene shows three different features. At 280 eV, in the pre-edge region, we observe an oscillating line that appears few femtoseconds after the temporal overlap. The oscillation period corresponds to 20 fs matching the C-C stretching mode3. At 286 eV another oscillating line appears with the same period but opposite phase. Finally, in the post-edge region, different lines appear with a more complex structure. In the case of ethane, a lower signal-to-noise ratio is obtained but similar features can be observed is the main difference that the edge and pre-edge lines are oscillating in phase.

FIGURE: The left (right) figure represents the time-resolve difference in the absorption spectra induced

by the pump pulse for ethylene (ethane).

Notes and References 1. Shaohao Chen, M. Justine Bell et al. Phys. Rev. A 2012, 86, 063408 2. Thomas Gaumnitz, Arohi Jain et al. Opt. Express 2017, 25, 27506-27518 3. Shimanouchi, T. , Tables of Molecular Vibrational Frequencies, Consolidated Volume 1, NSRDS NBS-39

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INVITED Ultrafast Spectroscopy of Organic Materials for Energy

Applications Larry Lüera,b

aMaterials for Energy and Electronics Technology (i-MEET), University of Erlangen, Germany. Tel: +49 9131 27634; bIMDEA Nanociencia, Calle Faraday, 9, 28049 Cantoblanco (Spain)


The introduction of non-fullerene acceptors (NFA) for bulk heterojunction organic photovoltaics (OPV) led to a decisive increase of power conversion efficiencies (PCE), now reaching 16% in single junction devices. A further increase towards the theoretical limits is only possible if for every individual process, kinetics and energetics are fine tuned to minimize energetic as well as quantum losses. Besides novel materials, knowledge of properties of the nanostructure is a key handle for device optimization. We show how ultrafast techniques can help achieving this goal.

We use femtosecond transient absorption (TA) spectroscopy in combination with matrix based decomposition techniques to quantify key parameters for the efficiency optimzation in organic solar cells comprising NFA. Determining the amount of exciton delocalization, we can assess whether exciton dissociation is diffusion – or reaction limited [1,2], enabling targeted strategies for nanostructure optimization. Although TA spectroscopy is intrinsically a bulk technique, we can distinguish interfacial processes from those occurring in the bulk by using interface specific optical probes. Thus, we can see whether in a bulk heterojunction, exciton dissociation occurs at the interface or in the bulk. In the latter case, charge transfer across the interface involves a single carrier and is loss-free [1]. Creation of free, extractable bulk carriers from bound interfacial charge-transfer states can be traced by the evolution of the transient Stark effect. Finally, we discuss how the evolution of novel experimental techniques with better time resolution is helping to understand charge separation.

Fig. 1. Transient absorption spectra (after pumping at 2.0 eV with 150 fs pulses) in a blend of p-DTS(FBTTh2)2 : NIDCS-MO before (a) and after (b) annealing at pump-probe delay times as given in the legend. Optical probes are indicated by shaded background. Annealing leads to a much longer singlet lifetime, but the structural purity of the small-molecule blend avoids excessive exciton dissociation losses. Redrawn after [1].

Notes and References 1 Shi, J.; Isakova, A., et al., Energy Environ. Sci. 2018, 11, 211 2 Isakova, A., Karuthedath, S., et al., Nanoscale 2018, 10, 10943

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INVITED Ultrafast Spectroscopy of Organic Materials for Energy

Applications Larry Lüera,b

aMaterials for Energy and Electronics Technology (i-MEET), University of Erlangen, Germany. Tel: +49 9131 27634; bIMDEA Nanociencia, Calle Faraday, 9, 28049 Cantoblanco (Spain)


The introduction of non-fullerene acceptors (NFA) for bulk heterojunction organic photovoltaics (OPV) led to a decisive increase of power conversion efficiencies (PCE), now reaching 16% in single junction devices. A further increase towards the theoretical limits is only possible if for every individual process, kinetics and energetics are fine tuned to minimize energetic as well as quantum losses. Besides novel materials, knowledge of properties of the nanostructure is a key handle for device optimization. We show how ultrafast techniques can help achieving this goal.

We use femtosecond transient absorption (TA) spectroscopy in combination with matrix based decomposition techniques to quantify key parameters for the efficiency optimzation in organic solar cells comprising NFA. Determining the amount of exciton delocalization, we can assess whether exciton dissociation is diffusion – or reaction limited [1,2], enabling targeted strategies for nanostructure optimization. Although TA spectroscopy is intrinsically a bulk technique, we can distinguish interfacial processes from those occurring in the bulk by using interface specific optical probes. Thus, we can see whether in a bulk heterojunction, exciton dissociation occurs at the interface or in the bulk. In the latter case, charge transfer across the interface involves a single carrier and is loss-free [1]. Creation of free, extractable bulk carriers from bound interfacial charge-transfer states can be traced by the evolution of the transient Stark effect. Finally, we discuss how the evolution of novel experimental techniques with better time resolution is helping to understand charge separation.

Fig. 1. Transient absorption spectra (after pumping at 2.0 eV with 150 fs pulses) in a blend of p-DTS(FBTTh2)2 : NIDCS-MO before (a) and after (b) annealing at pump-probe delay times as given in the legend. Optical probes are indicated by shaded background. Annealing leads to a much longer singlet lifetime, but the structural purity of the small-molecule blend avoids excessive exciton dissociation losses. Redrawn after [1].

Notes and References 1 Shi, J.; Isakova, A., et al., Energy Environ. Sci. 2018, 11, 211 2 Isakova, A., Karuthedath, S., et al., Nanoscale 2018, 10, 10943

INVITED Measuring Electronic and Lattice with Attosecond X-ray

Absorption spectroscopy Nicola Di Paloa, Daniel E. Rivasa,b, Themistoklis P. H. Sidiropoulosa, Stefano Severinoa, Maurizio Reduzzia, Bárbara Buadesa, Thomas Danzc, Claus Ropersc, Yves Jolyd, Manuel Valdivarese, Pierluigi Gargianie, Eric Pellegrine, Jens Biegerta,f aICFO - The Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain bEuropean XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany c4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany dInstitut Néel, CNRS, 25 Avenue des Martyrs, F-38042 Grenoble, France eALBA synchrotron, Carrer de la Llum, 2-26, E-08290 Cerdanyola del Vallés, Barcelona, Spain fICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain. E-mail: [email protected] Time resolving photo-induced structural changes in matter, requires the tracking of initial electronic excitations and their further connection and impact on the local structure. This is a challenging endeavor, as traditional techniques can only separately address either the electronic dynamics or the changes on the atomic structure. X-ray absorption fine-structure (XAFS) spectroscopy is a well-established technique capable to extract information on the electronic and lattice structure of a material with atomic resolution. Combining its capabilities with the temporal resolution provided by attosecond soft X-ray pulses produced via high-harmonic generation (HHG) could solve this problem. Important for the realization of attosecond XAFS is the adaptation of the technique to the specifics of high harmonic sources: they provide lower photon flux compared to the case of large-scale X-ray sources, but have broadband spectral coverage and extremely short pulse duration [1, 2].

Here, we present the simultaneously access to electronic and lattice parameters via XAFS spectroscopy using isolated attosecond soft X-ray pulses covering the entire water window region (280 eV to 540 eV) [1] with a pulse duration below ~300 as [2]. Spectral absorption measurements are achieved through a dispersive approach, with an imaging x-ray spectrograph designed for the soft x-ray spectral region. We demonstrate the novel capabilities of attosecond XAFS by identifying the σ* and π* orbital contributions to the density of states in highly oriented pyrolithic graphite (HOPG) simultaneously with the four characteristic bonding distances of graphite’s hexagonal lattice [3]. By changing the angle between the sample and the incident p-polarized x-rays from 0° to 40° the probe becomes sensitive to the out-of-plane electronic and lattice structure of graphite. These results are in agreement with measurements realized at a synchrotron, together with density functional theory calculations.

Fig. 1 (a) XAFS spectrum of 95 nm graphite sample measured at 0 and 39 degrees. In the XANES region, transitions to the unoccupied states σ* and π* are highlighted. The EXAFS region presents modulations produced by scattering of high-energy photoelectron with the surrounding electron density (inset). (b) Comparison between XAFS spectrum measured at 39 degrees and numerical simulations performed with FDMNES, capable to reproduce spectral features over a broad energy range.

[1] S. M. Teichmann et al., “0.5-keV Soft X-ray attosecond continua”, Nat. Commun. 7, 11493 (2016). [2] S. L. Cousin et al., “Attosecond Streaking in the water window: a new regime of attosecond pulse characterization”, Phys. Rev. X. 7,

041030 (2017). [3] B. Buades et al., “Dispersive soft X-ray absorption fine structure spectroscopy in graphite with an attosecond pulse”, Optica 5, 5 (2018).

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INVITED VEGA laser facility: characterization and beamlines

management C. Méndez, O. Varela, E. García, I. Hernández, J. Ajates, J.D. Pisonero, J.L. Sagredo, M.

Olivar and L. Roso Centro de Láseres Pulsados , Edificio M5. Parque Científico. C/Adaja, 8. 37185 Villamayor, Salamanca, Spain Tel: +34 923338121;


VEGA system is a petawatt laser facility belonging to the Spanish Pulsed Lasers Center that makes it possible to develop experiments for exploring the physics of interactions of intense lasers with matter.

The Ti:Sapphire Chirped Pulse Amplification-based laser chain includes three common frontend outputs at 1 PW, 150 TW and 15 TW. These beamlines have a central 800 nm wavelength, 30 fs temporal width and work at 1 Hz, 10 Hz and 10 Hz respectively.

This configuration, as well as the near future installation of additional laser systems synchronized with VEGA laser chain, opens the possibility of multiple pump-probe experiments. For doing so, reliable laser sources with proper pulse characterization, enough beam quality and shot to shot and day to day reproducibility become key elements of the facility. The transition towards a user collaborative research infrastructure has also been accompanied by an effort for getting enhanced operational results and experiment planning and implementation.

In this work we discuss these facility-quality elements as well as preliminary experimental results and near future improvement plans for different outputs synchronization.

Further highlights of operational experience obtained from the first user access call developed during 2018 are also presented1.

FIGURE: Setup for VEGA beamline facility management.

References 1 M. Huault, G. Zeraouli, J. G. Ajates, J. Apiñaniz, E. García, I. Hernández, S. Malko, C. Méndez, J. A. Perez, J.D. Pisonero, C. Salgado,

X. Vaisseau, O. Varela, G. Gatti, L. Volpe, L. Roso, R. Fedosejevs, A. Longman, R. Shepherd, and W. T. Hill, "Commissioning experiments of VEGA-2 at Centro de Láseres Pulsados (CKPU)," Frontiers in Optics. OSA Technical Digest (online) (Optical Society of America, 2017), paper FM2B.4.

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INVITED VEGA laser facility: characterization and beamlines

management C. Méndez, O. Varela, E. García, I. Hernández, J. Ajates, J.D. Pisonero, J.L. Sagredo, M.

Olivar and L. Roso Centro de Láseres Pulsados , Edificio M5. Parque Científico. C/Adaja, 8. 37185 Villamayor, Salamanca, Spain Tel: +34 923338121;


VEGA system is a petawatt laser facility belonging to the Spanish Pulsed Lasers Center that makes it possible to develop experiments for exploring the physics of interactions of intense lasers with matter.

The Ti:Sapphire Chirped Pulse Amplification-based laser chain includes three common frontend outputs at 1 PW, 150 TW and 15 TW. These beamlines have a central 800 nm wavelength, 30 fs temporal width and work at 1 Hz, 10 Hz and 10 Hz respectively.

This configuration, as well as the near future installation of additional laser systems synchronized with VEGA laser chain, opens the possibility of multiple pump-probe experiments. For doing so, reliable laser sources with proper pulse characterization, enough beam quality and shot to shot and day to day reproducibility become key elements of the facility. The transition towards a user collaborative research infrastructure has also been accompanied by an effort for getting enhanced operational results and experiment planning and implementation.

In this work we discuss these facility-quality elements as well as preliminary experimental results and near future improvement plans for different outputs synchronization.

Further highlights of operational experience obtained from the first user access call developed during 2018 are also presented1.

FIGURE: Setup for VEGA beamline facility management.

References 1 M. Huault, G. Zeraouli, J. G. Ajates, J. Apiñaniz, E. García, I. Hernández, S. Malko, C. Méndez, J. A. Perez, J.D. Pisonero, C. Salgado,

X. Vaisseau, O. Varela, G. Gatti, L. Volpe, L. Roso, R. Fedosejevs, A. Longman, R. Shepherd, and W. T. Hill, "Commissioning experiments of VEGA-2 at Centro de Láseres Pulsados (CKPU)," Frontiers in Optics. OSA Technical Digest (online) (Optical Society of America, 2017), paper FM2B.4.

INVITED

Mapping nonadiabatic molecular dynamics with time-resolved Coulomb explosion images

R. de Nalda*a, M.E. Corralesb, J. González-Vázquezc and L. Banaresb aInstituto de Química Física Rocasolano, CSIC, Serrano, 119, 28006 Madrid, Spain. bDepartamento de Química Física (Unidad Asociada I+D+i del CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain. cDepartamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.

E-mail: [email protected] The phenomenon of molecular Coulomb explosion takes place when two or more electrons are ejected simultaneously or in a very short time interval, and as a result the charged components of the molecular system undergo explosion due to the strong electrostatic repulsion. The measurement of the final velocity vectors of the fragments resulting from the process [1] can provide valuable information on the geometry of molecules [2] or clusters [3], the alignment or orientation of a molecular ensemble in the laboratory frame [4], and can even provide a tool for the identification of isomers or enantiomers [5]. In this work we propose a method based on Coulomb explosion to directly map the presence of conical intersections encountered by a propagating wave packet in a molecular system [6] and will show its application to nonadiabatic dissociation of CH3I.

Figure. Abel-inverted velocity map images of the CH3

+ cation as obtained after UV A-band dissociation of CH3I and probing with an intense NIR field at the delays indicated. The DISS label indicates single ionization and the CE label indicates Coulomb explosion channels. Acknowledgements Funding from MINECO (Spain) through grants CTQ2015-65033-P and CTQ2016-75880-P is gratefully acknowledged.

References 1 M. E. Corrales et al., Journal of Physical Chemistry A 2012, 116, 2669. 2 J. Gagnon et al., Journal of Physics B-Atomic Molecular and Optical Physics 2008, 41, 6. 3 J. Voigtsberger et al., Nature Communications 2014, 5, 6. 4 K. Amini et al., Journal of Chemical Physics 2017, 147, 8. 5 M. Burt et al., Journal of Chemical Physics 2018, 148, 5. 6 M.E. Corrales et al., J. Phys. Chem. Lett. 2019, 10, 138.

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ORAL Witnessing the ultrafast dynamics within Ce-based MOFs: relevance to

photonics and photocatalysis

Elena Caballero-Mancebo, Boiko Cohen, and Abderrazzak Douhal* Dpto. de Química Física, Facultad de Ciencias Ambientales y Bioquímica and INAMOL, Universidad de Castilla-La Mancha, Avda Carlos III s/n 4071 Toledo. *corresponding author: [email protected] Cycldextrins and silica-based materials are the most used host pockets and pores to confine chemical and biological molecules allowing changes in their spectroscopy (1-3). Metal-organic frameworks (MOFs) are emerging confining materials of luminescent and photochemical applications (4-6). Armed with femto to millisecond spectroscopies, we unravelled the photobehaviors of two Ce-based MOFs: Ce-NU-1000 and Ce-CAU-24-TBAPy (7). We observed that both MOFs show ligand-to-cluster charge transfer reactions in ~100 and ~70 fs for Ce-NU-1000 and Ce-CAU-24-TBAPy, respectively. The formed charge separated states, resulting in electron and hole generation, recombine in different times for each MOF, being longer in Ce-CAU-24-TBAPy: 1.59 and 13.43 µs than in Ce-NU-1000: 0.64 and 4.91 µs. The linkers in both MOFs also undergo a very fast intramolecular charge transfer reaction in ~160 fs. Furthermore, Ce-NU-1000 MOF reveals excimer formation in 50 ps, and lifetime of ~ 14 ns. The lack of this inter-linkers event in Ce-CAU-24-TBAPy arises from topological restriction and demonstrates the structural differences between the two frameworks. Fig. 1 illstrates the observed events and times. The observed results are relevant to photocatalysis and photonics.

Fig. 1: Cartoon illustrating the ultrafast dynamics of Ce-NU-1000 and Ce-CAU-24-TBAPy MOFs. Acknowledgements: This work was supported by MINECO through project MAT2017-86532-R. E.C.-B. thanks the

MINECO for the FPI fellowship. References: 1. A. Douhal, Chem. Rev. 104, 1955–1976 (2004). 2. N. Alarcos, B. Cohen, M. Ziolek and A. Douhal, Chem. Rev., 117(22), 13639-13720 (2017). 3. Chemistry of Silca- and Zeolite-based Materials Synthesis, Characterization, and Applications”, A. Douhal, M.

Anpo (Edits.), Elsevier, ISBN:9780128178133 (2019). 4. M. Gutiérrez, F. Sánchez and A. Douhal, J. Mater. Chem. C, 3 (2015) 11300-11310. 5. M. Gutiérrez, C. Martín, K. Kennes, J. Hofkens, M. Van der Auweraer, F. Sánchez and A. Douhal, Adv. Opt.

Mater., 2018 DOI: 10.1002/adom.201701060 (2018). 6. E. Caballero-Mancebo, B. Cohen, J. M. Moreno, A. Corma, U. Díaz and A. Douhal, ACS Applied Materials &

Interfaces, 10(38), 32885-2894 (2018). 7. E. Caballero-Mancebo, Boiko Cohen S. Smolders, D. de Vois and A. Douhal, Adv. Science, 1901020. DOI:

10.1002/advs.201901020 (2019).

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ORAL Witnessing the ultrafast dynamics within Ce-based MOFs: relevance to

photonics and photocatalysis

Elena Caballero-Mancebo, Boiko Cohen, and Abderrazzak Douhal* Dpto. de Química Física, Facultad de Ciencias Ambientales y Bioquímica and INAMOL, Universidad de Castilla-La Mancha, Avda Carlos III s/n 4071 Toledo. *corresponding author: [email protected] Cycldextrins and silica-based materials are the most used host pockets and pores to confine chemical and biological molecules allowing changes in their spectroscopy (1-3). Metal-organic frameworks (MOFs) are emerging confining materials of luminescent and photochemical applications (4-6). Armed with femto to millisecond spectroscopies, we unravelled the photobehaviors of two Ce-based MOFs: Ce-NU-1000 and Ce-CAU-24-TBAPy (7). We observed that both MOFs show ligand-to-cluster charge transfer reactions in ~100 and ~70 fs for Ce-NU-1000 and Ce-CAU-24-TBAPy, respectively. The formed charge separated states, resulting in electron and hole generation, recombine in different times for each MOF, being longer in Ce-CAU-24-TBAPy: 1.59 and 13.43 µs than in Ce-NU-1000: 0.64 and 4.91 µs. The linkers in both MOFs also undergo a very fast intramolecular charge transfer reaction in ~160 fs. Furthermore, Ce-NU-1000 MOF reveals excimer formation in 50 ps, and lifetime of ~ 14 ns. The lack of this inter-linkers event in Ce-CAU-24-TBAPy arises from topological restriction and demonstrates the structural differences between the two frameworks. Fig. 1 illstrates the observed events and times. The observed results are relevant to photocatalysis and photonics.

Fig. 1: Cartoon illustrating the ultrafast dynamics of Ce-NU-1000 and Ce-CAU-24-TBAPy MOFs. Acknowledgements: This work was supported by MINECO through project MAT2017-86532-R. E.C.-B. thanks the

MINECO for the FPI fellowship. References: 1. A. Douhal, Chem. Rev. 104, 1955–1976 (2004). 2. N. Alarcos, B. Cohen, M. Ziolek and A. Douhal, Chem. Rev., 117(22), 13639-13720 (2017). 3. Chemistry of Silca- and Zeolite-based Materials Synthesis, Characterization, and Applications”, A. Douhal, M.

Anpo (Edits.), Elsevier, ISBN:9780128178133 (2019). 4. M. Gutiérrez, F. Sánchez and A. Douhal, J. Mater. Chem. C, 3 (2015) 11300-11310. 5. M. Gutiérrez, C. Martín, K. Kennes, J. Hofkens, M. Van der Auweraer, F. Sánchez and A. Douhal, Adv. Opt.

Mater., 2018 DOI: 10.1002/adom.201701060 (2018). 6. E. Caballero-Mancebo, B. Cohen, J. M. Moreno, A. Corma, U. Díaz and A. Douhal, ACS Applied Materials &

Interfaces, 10(38), 32885-2894 (2018). 7. E. Caballero-Mancebo, Boiko Cohen S. Smolders, D. de Vois and A. Douhal, Adv. Science, 1901020. DOI:

10.1002/advs.201901020 (2019).

ORAL Structural dynamics effects on the UV electronic

predissociation of alkyl iodides at 201 nm M. L. Murillo-Sánchez,a A. Zanchet,b,c S. Marggi Poullain,d,e J. Gonzalez-Vázquezd and L.

Bañaresa

a Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain. Tel: +34 913945229 b Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37003, Salamanca, Spain. Tel: +34 923294500 c Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas., Serrano 123, 28006 Madrid, Spain. Tel: +34 91 561 6800 d Departamento de Química, Modulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. Tel: +34 914973008 e Present address: Department of Chemistry, University of California, Berkeley, California 94720, United States


In order to investigate the correlation between chemical structure and predissociation dynamics, femtosecond time-resolved velocity map ion imaging experiments have been carried out in the second absorption band (B-band) of a series of linear (CH3I, C2H5I, n-C3H7I, n-C4H9I) and branched alkyl iodides (i-C3H7I, t-C4H9I), at an excitation wavelength of 201.2 nm, i.e. around the wavelength where the origin of the B-band of CH3I originates and where several absorption maxima of the remaining alkyl iodides are found.1, 2

The energy distribution resulting from the angular integration of the measured asymptotic I*(2P1/2) fragment images obtained through (2+1) REMPI has allowed us to distribute the available energy content into translational and ro-vibrational content of the fragments.

Furthermore, predissociation lifetimes have been determined for all alkyl iodides from measurements of time-resolved I*(2P1/2) fragment images as a function of the time delay, images which also provide the angular character of the transition directly through the observation of fragments appearing early with respect to both predissociation lifetime and molecular rotation. The diminishing predissociation lifetimes reveal that an increasing linear structure seems to an enhanced coupling between the initial Rydberg and the repulsive states while the restructuring in a branched chain breaks this coupling most probable because we are exciting vibronic transitions, while in the first case we are exiciting the origin of the B-band. In all cases, at early times, it is observed a natural perpendicular character of transition which is loss over time due to molecular rotation, with a decreasing anisotropy variation over structural complexity presumably caused by a greater density of rotational states that favor the cooling of the molecular beam by collision in the beam.

The experimental results are supported by ab-initio theoretical calculations that include the spin-orbit interactions to give a qualitative description of the observed results, and thus be able to have a deeper view of the predissociation dynamics of this type of compounds and its structural dependency

Notes and References 1. R. Boschi and D. Salahub, Molecular Physics, 1972, 24, 289-299. 2. R. Boschi and D. Salahub, Molecular Physics, 1972, 24, 735-752.

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ORAL Migration and refractive index control in phosphate glasses by

femtosecond laser induced element redistribution Manuel Macías-Montero,*a Pedro Moreno-Zárate,b Antonio Dias,a Rocio Ariza,a,c Belen

Sotillo,c Paloma Fernandez,c Rosalía Sernaa and Javier Solisa a Laser Processing Group, Instituto de Optica (IO-CSIC), Serrano 121, 28006 Madrid, Spain b Industrial Engineering School, Tepexi Higher Technological Institute, Tepexi de Rodríguez 74690, Mexico c Department of Materials Physics, Faculty of Physics, University Complutense of Madrid, Madrid 28040, Spain

E-mail: [email protected] Femtosecond laser induced element redistribution (FLIER) processes in glass (see the review in Ref. [1]) is an interesting route to produce of photonic devices. Recent FLIER investigations have shown how to produce efficient photonics devices, such as waveguides [2,3], optical amplifiers, and lasers [4]. These works effectiveness rely on the addition of a small amount of a glass modifier that act as a refractive index carrier and a fast diffusing element (usually an alkali ion, like Na+ or K+). Upon fs-laser irradiation, cross migration of both types of glass modifier ions occurs, producing a significant refractive index contract that enables the production waveguides. In this work, experimental conditions are varied to stablish a solid control of the ion migration, and hence, of the refractive index contrast obtained via FLIER. In order to produce optical waveguides, a modified phosphate glass is used. The modification is induced by the addition of small amounts of La+ (index carrier) and K+ (fast diffusion ion) in the form of oxides. Structures are created using 350 fs-laser pulses, operating at 500kHz repetition rate and 1030 nm [5]. Morphological and compositional characterization is carried out by optical microscopy and energy-dispersive X-ray spectroscopy respectively. Performance of the waveguides produces is also evaluated [6]. Results show that it is possible to control the refractive index between 5·10-3 and 1.5·10-2 by tuning the writing velocity of the devices. Simultaneously, mode field diameters (MFD) measured at the exit of waveguides are also controllably tuned, ranging values from 6 to 18 µm. The use of a velocity ramp enables the production of tapper structures that are able to convert MFDs with low losses. These results show that the experimental approach is adequate to produce highly versatile and efficient photonic devices.

Figure. (a) Optical cross-section images of waveguides written at the indicated velocities. (b) Propagated mode images at 1640 nm. (c) Mode field diameter versus writing velocity.

Notes and References 1 Fernandez, T. T. ; Sakakura, M.; Eaton, S. M.; Sotillo, B.; Siegel, J.; Solis, J.; Shimotsuma, Y.; Miura, K. Prog. Mater. Sci. 2018, 94,

68–113 2 Toney Fernandez, T.; Haro-González, P.; Sotillo, B.; Hernandez, M.; Jaque, D.; Fernandez, P.; Domingo, C.; Siegel, J.; Solis, J. Opt.

Lett. 2013, 38, 5248–51 3 Del Hoyo, J. ; Vazquez, R. M.; Sotillo, B.; Fernandez, T. T.; Siegel, J.; Fernández, P.; Osellame, R.; Solis, J. Appl. Phys. Lett. 2014,

105, 131101 4 del Hoyo, J. ; Moreno-Zarate, P.; Escalante, G.; Valles, J. A.; Fernandez, P.; Solis, J. J. Light. Technol. 2017, 35, 2955–2959 5 Dias, A.; Muñoz, F.; Alvarez, A.; Moreno-Zárate, P.; Atienzar, J.; Urbieta, A.; Fernandez, P.; Pardo, M.; Serna, R.; Solis, J. Opt. Lett.

2018, 43, 2523 6 Moreno-Zarate, P.; Gonzalez, A.; Funke, S.; Días, A.; Sotillo, B.; del Hoyo, J.; Garcia-Pardo, M.; Serna, R.; Fernandez, P.; Solis, J.

Phys. status solidi 2018, 1800258, 1–6

60 µm/s 240 µm/s 600 µm/sa)

b)

c)

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ORAL Migration and refractive index control in phosphate glasses by

femtosecond laser induced element redistribution Manuel Macías-Montero,*a Pedro Moreno-Zárate,b Antonio Dias,a Rocio Ariza,a,c Belen

Sotillo,c Paloma Fernandez,c Rosalía Sernaa and Javier Solisa a Laser Processing Group, Instituto de Optica (IO-CSIC), Serrano 121, 28006 Madrid, Spain b Industrial Engineering School, Tepexi Higher Technological Institute, Tepexi de Rodríguez 74690, Mexico c Department of Materials Physics, Faculty of Physics, University Complutense of Madrid, Madrid 28040, Spain

E-mail: [email protected] Femtosecond laser induced element redistribution (FLIER) processes in glass (see the review in Ref. [1]) is an interesting route to produce of photonic devices. Recent FLIER investigations have shown how to produce efficient photonics devices, such as waveguides [2,3], optical amplifiers, and lasers [4]. These works effectiveness rely on the addition of a small amount of a glass modifier that act as a refractive index carrier and a fast diffusing element (usually an alkali ion, like Na+ or K+). Upon fs-laser irradiation, cross migration of both types of glass modifier ions occurs, producing a significant refractive index contract that enables the production waveguides. In this work, experimental conditions are varied to stablish a solid control of the ion migration, and hence, of the refractive index contrast obtained via FLIER. In order to produce optical waveguides, a modified phosphate glass is used. The modification is induced by the addition of small amounts of La+ (index carrier) and K+ (fast diffusion ion) in the form of oxides. Structures are created using 350 fs-laser pulses, operating at 500kHz repetition rate and 1030 nm [5]. Morphological and compositional characterization is carried out by optical microscopy and energy-dispersive X-ray spectroscopy respectively. Performance of the waveguides produces is also evaluated [6]. Results show that it is possible to control the refractive index between 5·10-3 and 1.5·10-2 by tuning the writing velocity of the devices. Simultaneously, mode field diameters (MFD) measured at the exit of waveguides are also controllably tuned, ranging values from 6 to 18 µm. The use of a velocity ramp enables the production of tapper structures that are able to convert MFDs with low losses. These results show that the experimental approach is adequate to produce highly versatile and efficient photonic devices.

Figure. (a) Optical cross-section images of waveguides written at the indicated velocities. (b) Propagated mode images at 1640 nm. (c) Mode field diameter versus writing velocity.

Notes and References 1 Fernandez, T. T. ; Sakakura, M.; Eaton, S. M.; Sotillo, B.; Siegel, J.; Solis, J.; Shimotsuma, Y.; Miura, K. Prog. Mater. Sci. 2018, 94,

68–113 2 Toney Fernandez, T.; Haro-González, P.; Sotillo, B.; Hernandez, M.; Jaque, D.; Fernandez, P.; Domingo, C.; Siegel, J.; Solis, J. Opt.

Lett. 2013, 38, 5248–51 3 Del Hoyo, J. ; Vazquez, R. M.; Sotillo, B.; Fernandez, T. T.; Siegel, J.; Fernández, P.; Osellame, R.; Solis, J. Appl. Phys. Lett. 2014,

105, 131101 4 del Hoyo, J. ; Moreno-Zarate, P.; Escalante, G.; Valles, J. A.; Fernandez, P.; Solis, J. J. Light. Technol. 2017, 35, 2955–2959 5 Dias, A.; Muñoz, F.; Alvarez, A.; Moreno-Zárate, P.; Atienzar, J.; Urbieta, A.; Fernandez, P.; Pardo, M.; Serna, R.; Solis, J. Opt. Lett.

2018, 43, 2523 6 Moreno-Zarate, P.; Gonzalez, A.; Funke, S.; Días, A.; Sotillo, B.; del Hoyo, J.; Garcia-Pardo, M.; Serna, R.; Fernandez, P.; Solis, J.

Phys. status solidi 2018, 1800258, 1–6

60 µm/s 240 µm/s 600 µm/sa)

b)

c)

PLENARY XUV induced dynamics in large polyatomic systems:

Ultrafast charge and energy flow Lépine Franck

aUniv Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, VILLEURBANNE, France. Tel: 33 472431913 E-mail: [email protected]

Modern ultrashort X-ray/XUV sources provide unique tools to study the primary photoinduced-reactions in atoms, molecules and solid upon energetic excitation1. Understanding these processes on the femtosecond (10-15 s) and attosecond (10-18 s) timescales is expected to impact other reseach fields including biology, solid-state physics or electronics. In this presentation, we will show that ultrashort XUV pulses can be used to track attosecond and femtosecond processes even in large polyatomic systems for which many-body quantum effects play a major role (see figure 1). This will be illsutrated in the case of large carbon based 2D molecules such as PAH2,3. We will also show perspectives in the investigation of large biologically relevant systems for which charge and conformations play a crucial role and require specific tools.

Figure1 : Time-dependent evolution of the excited states of naphthalene cations following XUV ionization. Strongly coupled electron correlation and non-adiabatic dynamics determine the ultrafast dynamics of the system leading to a trapping of excited population over several 10 fs.

Notes and References 1 F. Lépine et al . Nature Phot. 2014, 8, 195–204 2 A. Marciniak et al. Nat. Commun. 2015, 6, 7909 3 A. Marciniak et al. Nat. Commun. 2019, 10, 337

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INVITED Rotational dynamics of complex molecules in external fields

Rosario González-Féreza aInstituto Carlos I de Física Teórica y Computacional and Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada, Spain


Fixing molecules in space is the goal of many theoretical and experimental works because it facilitates the study of their structure and dynamics. Techniques used to fix molecules in space include adiabatic and impulsive alignment and mixed-field orientation. Strong degrees of alignment and orientation have been achieved for different symmetric and asymmetric top molecules using these methods. In the first part of this talk, we theoretically investigate the rotational dynamics of molecules without rotational symmetry in combined non-resonant laser fields and static electric fields. It was experimentally demonstrated that asymmetric top molecules with a permanent dipole moment non parallel to any principal axis of polarizability can be 3D aligned and orientated using elliptically polarized laser pulses in combination with weak dc electric fields [1]. Here, we solve the time-dependent Schrödinger equation for different field configurations for 6-chloropyridazine-3-carbonitrile (CPC) and show that nonadiabatic phenomena play an important role on its mixed field orientation dynamics [2]. In the second part, we theoretically investigate the impact of the coupling of the rotational angular momentum and internal rotation on the alignment and mixed-field orientation of different molecular systems. As an example, we analyze the adiabatic alignment and mixed-field orientation of the prototypical indole(H2O) cluster where the water molecule undergoes and internal rotation. Our results for the rotational and torsional dynamics show that the coupling of the internal and overall rotation is small and that indole(H2O) can be treated as a rigid molecule for typical laser field strengths used in experiments. In addition, we explore the parameter space for which this approximation holds and when the field-free and field-induced coupling of the two motions can no longer be neglected [3]. Finally, we present a time-dependent study on how the hyperfine coupling due to the nulear-quadrupole interactions affects the rotational dynamics of asymmetric top molecules in a non-resonant laser field [4].

Notes and References 1. J. L. Hansen et al., J. Chem. Phys. 139, 234313 (2013) 2. L. V. Thesing , J. Küpper , and R. González-Férez, J. Chem. Phys. 146, 244304 (2017) 3. L. V. Thesing, A. Yachmenev, R. González-Férez, and J. Küpper, Phys. Rev. A 98, 053412 (2018) 4. L. V. Thesing, A. Yachmenev, R. González-Férez, and J. Küpper, preprint (2019)

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INVITED Rotational dynamics of complex molecules in external fields

Rosario González-Féreza aInstituto Carlos I de Física Teórica y Computacional and Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada, Spain


Fixing molecules in space is the goal of many theoretical and experimental works because it facilitates the study of their structure and dynamics. Techniques used to fix molecules in space include adiabatic and impulsive alignment and mixed-field orientation. Strong degrees of alignment and orientation have been achieved for different symmetric and asymmetric top molecules using these methods. In the first part of this talk, we theoretically investigate the rotational dynamics of molecules without rotational symmetry in combined non-resonant laser fields and static electric fields. It was experimentally demonstrated that asymmetric top molecules with a permanent dipole moment non parallel to any principal axis of polarizability can be 3D aligned and orientated using elliptically polarized laser pulses in combination with weak dc electric fields [1]. Here, we solve the time-dependent Schrödinger equation for different field configurations for 6-chloropyridazine-3-carbonitrile (CPC) and show that nonadiabatic phenomena play an important role on its mixed field orientation dynamics [2]. In the second part, we theoretically investigate the impact of the coupling of the rotational angular momentum and internal rotation on the alignment and mixed-field orientation of different molecular systems. As an example, we analyze the adiabatic alignment and mixed-field orientation of the prototypical indole(H2O) cluster where the water molecule undergoes and internal rotation. Our results for the rotational and torsional dynamics show that the coupling of the internal and overall rotation is small and that indole(H2O) can be treated as a rigid molecule for typical laser field strengths used in experiments. In addition, we explore the parameter space for which this approximation holds and when the field-free and field-induced coupling of the two motions can no longer be neglected [3]. Finally, we present a time-dependent study on how the hyperfine coupling due to the nulear-quadrupole interactions affects the rotational dynamics of asymmetric top molecules in a non-resonant laser field [4].

Notes and References 1. J. L. Hansen et al., J. Chem. Phys. 139, 234313 (2013) 2. L. V. Thesing , J. Küpper , and R. González-Férez, J. Chem. Phys. 146, 244304 (2017) 3. L. V. Thesing, A. Yachmenev, R. González-Férez, and J. Küpper, Phys. Rev. A 98, 053412 (2018) 4. L. V. Thesing, A. Yachmenev, R. González-Férez, and J. Küpper, preprint (2019)

INVITED Single photon hot eletron ionization of fullerenes

Klavs Hansen,*a

aCenter for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin, P.R. China. Tel:+86 130 1136 5825

E-mail: [email protected] The ionization of neutral molecules and electron detachment of anions can proceed in thermal processes, analogously to the bulk thermionic emission. The process involves thermal excitations of valence electrons to a vacuum state by coupling of vibrational and electronic degrees of freedom. Such processes will occur on time scales beyond the coupling time, which is typically on the order of a picosecond. Electronic excitations that occur on shorter time scales will cause the excitation to reside in the electronic states. Such transiently excited electronic system may also emit thermal electrons. The effective temperatures in these hot electron emissions is on the order of 1 eV. Hot electron emission has been observed from several large molecules and clusters, including the fullerenes, PAH molecules and metal clusters after multiphoton excitation with near-infrared and UV photons in femtosecond laser pulses [1,2,3,4].

Recently hot electron emission was been also observed in fullerenes after the absorption of a single, high energy photon [5,6]. I will present results from these experiments and discuss the implications for the electron-electron relaxation mechanism and the observation of the effect in other systems.

The electron kinetic energy distribution measured in coincidence with the fragmented fullerene C58

+ after absorption of a 52 eV photon The fragmentation occurs after the electron emission. Also shown is the fitted exponential distribution expected for a thermal emission. The fitted electron temperature is 1.6 eV.

Notes and References 1 E.E.B. Campbell et al., The Laser Pulse Duration Dependence of C60 Photoelectron Spectra, Phys. Rev. Lett. 2000, 84, 2128 2 R. Schlipper, R. Kusche, B. v. Issendorff, and H. Haberland, Thermal emission of electrons from highly excited sodium clusters, Appl. Phys. A 2001, 72, 255 3 M. Kjellberg, O. Johansson, F. Jonsson, A.V. Bulgakov, C. Bordas, E.E.B. Campbell, and K. Hansen, Momentum map imaging photoelectron spectroscopy of fullerenes with femtosecond laser pulses, Phys. Rev. A 2010, 81, 023202 4 M. Kjellberg, A.V. Bulgakov, M. Goto, O. Johansson, and K. Hansen, Femtosecond electron spectroscopy of coronene, benzo[GHI]perylene and anthracene, J. Chem. Phys. 2010, 133, 074308 5 Klavs Hansen, et al., Single photon thermal ionisation of C60, Phys. Rev. Lett. 2017, 118, 103001 6 Vitali Zhaunerchyk, Single photon thermal ionisation of C70, to be published

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INVITED Accelerated twist at the ultrafast: the self-torque of light

Carlos Hernández-García

Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, University of Salamanca, Salamanca E-37008. Tel: +34 923294678;

E-mail: [email protected] Ultrashort pulses of coherent structured light—light fields with custom spatial and temporal properties, such as intensity, phase and angular momentum—are opening excellent opportunities to control the primary electronic response of matter. In particular, topological light beams carrying angular momentum are particularly interesting, as they interact with matter differently, introducing mechanical motion to nano-structures, and affecting fundamental excitation rules. Light angular momentum is two-fold: spin angular momentum (SAM), related to the polarization of light; and orbital angular momentum (OAM), associated to the spatial profile of the phase of the electromagnetic wave. While angular momentum can be routinely transferred to visible/infrared (IR) beams it becomes a lot harder in the extreme-ultraviolet (EUV) and x-ray regimes. The nonlinear frequency upconversion of an intense IR femtosecond laser pulse through high harmonic generation (HHG) has emerged as a robust mechanism to imprint SAM and OAM onto the EUV regime [1-3], providing structured attosecond pulses with controlled angular momentum properties.

We introduce a new class of light beams that possess a unique property associated with an ultrafast temporal variation of their OAM: the self-torque of light [4]. Self-torque naturally arises in EUV beams generated through HHG, when driven by two time-delayed IR pulses carrying different OAM (Fig. 1). Our work not only presents and confirms an inherently new property of light beams, but also opens up a route for the study of systems with time-varying OAM. Thanks to their ultrafast nature, EUV self-torqued beams can be extraordinary tools for laser-matter manipulation on attosecond time and nanometer spatial scales.

Figure 1. Generation of EUV harmonic beams with self-torque (time-dependent OAM). Two time-delayed, femtosecond infrared (IR) pulses with different OAM are focused into a gas target to produce self-torqued EUV beams through HHG. The unique signature of self-torqued beams is their time-dependent OAM, as shown in the right inset for the 17th harmonic [4].

References 1 K. M. Dorney, L. Rego, N. J. Brooks, J. San Román, C.-T. Liao, J. L. Ellis, D. Zusin, C. Gentry, Q. L. Nguyen, J. M. Shaw, A. Picón,

L. Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, “Controlling the polarization and vortex charge of attosecond high-harmonic beams via simultaneous spin-orbit momentum conservation”, Nature Photonics 13,123–130 (2019).

2 E. Pisanty, L. Rego, J. San Román, A. Picón, K. M. Dorney, H. C. Kapteyn, M. M. Murnane, L. Plaja, M. Lewenstein and C. Hernández-García, “Conservation of torus-knot angular momentum in high-order harmonic generation” Phys. Rev. Lett. 122, 203201 (2019).

3 C. Hernández-García, et al. “Extreme ultraviolet vector beams driven by infrared lasers”, Optica 4, 2334–2536 (2017). 4 L. Rego, K. M. Dorney, N. J. Brooks, Q. L. Nguyen, C.-Ting Liao, J. San Román, D. E. Couch, A. Liu, E. Pisanty, M. Lewenstein, L.

Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, “Generation of extreme-ultraviolet beams with time-varying orbital angular momentum”, Science 364, eaaw9486 (2019).

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INVITED Accelerated twist at the ultrafast: the self-torque of light

Carlos Hernández-García

Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, University of Salamanca, Salamanca E-37008. Tel: +34 923294678;

E-mail: [email protected] Ultrashort pulses of coherent structured light—light fields with custom spatial and temporal properties, such as intensity, phase and angular momentum—are opening excellent opportunities to control the primary electronic response of matter. In particular, topological light beams carrying angular momentum are particularly interesting, as they interact with matter differently, introducing mechanical motion to nano-structures, and affecting fundamental excitation rules. Light angular momentum is two-fold: spin angular momentum (SAM), related to the polarization of light; and orbital angular momentum (OAM), associated to the spatial profile of the phase of the electromagnetic wave. While angular momentum can be routinely transferred to visible/infrared (IR) beams it becomes a lot harder in the extreme-ultraviolet (EUV) and x-ray regimes. The nonlinear frequency upconversion of an intense IR femtosecond laser pulse through high harmonic generation (HHG) has emerged as a robust mechanism to imprint SAM and OAM onto the EUV regime [1-3], providing structured attosecond pulses with controlled angular momentum properties.

We introduce a new class of light beams that possess a unique property associated with an ultrafast temporal variation of their OAM: the self-torque of light [4]. Self-torque naturally arises in EUV beams generated through HHG, when driven by two time-delayed IR pulses carrying different OAM (Fig. 1). Our work not only presents and confirms an inherently new property of light beams, but also opens up a route for the study of systems with time-varying OAM. Thanks to their ultrafast nature, EUV self-torqued beams can be extraordinary tools for laser-matter manipulation on attosecond time and nanometer spatial scales.

Figure 1. Generation of EUV harmonic beams with self-torque (time-dependent OAM). Two time-delayed, femtosecond infrared (IR) pulses with different OAM are focused into a gas target to produce self-torqued EUV beams through HHG. The unique signature of self-torqued beams is their time-dependent OAM, as shown in the right inset for the 17th harmonic [4].

References 1 K. M. Dorney, L. Rego, N. J. Brooks, J. San Román, C.-T. Liao, J. L. Ellis, D. Zusin, C. Gentry, Q. L. Nguyen, J. M. Shaw, A. Picón,

L. Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, “Controlling the polarization and vortex charge of attosecond high-harmonic beams via simultaneous spin-orbit momentum conservation”, Nature Photonics 13,123–130 (2019).

2 E. Pisanty, L. Rego, J. San Román, A. Picón, K. M. Dorney, H. C. Kapteyn, M. M. Murnane, L. Plaja, M. Lewenstein and C. Hernández-García, “Conservation of torus-knot angular momentum in high-order harmonic generation” Phys. Rev. Lett. 122, 203201 (2019).

3 C. Hernández-García, et al. “Extreme ultraviolet vector beams driven by infrared lasers”, Optica 4, 2334–2536 (2017). 4 L. Rego, K. M. Dorney, N. J. Brooks, Q. L. Nguyen, C.-Ting Liao, J. San Román, D. E. Couch, A. Liu, E. Pisanty, M. Lewenstein, L.

Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, “Generation of extreme-ultraviolet beams with time-varying orbital angular momentum”, Science 364, eaaw9486 (2019).

INVITED Real-Time Imaging of Ultrafast Charge Dynamics in CF4

from Attosecond Pump-Probe Photoelectron Spectroscopy E. Plésiat*a, M. Lara-Astiasoa, P. Declevab, A. Palaciosa and F. Martína,c,d

aDepartamento de Química,Universidad Autónoma de Madrid, 28049 Madrid (Spain); bDipartimento di Scienze Chimiche e Farmaceutiche, Universitá di Trieste, 34127 Trieste (Italy); cInstituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nano), 28049 Madrid (Spain); dCondensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain);


Synopsis: Attosecond spectroscopy offers the possibility to track and control electron dynamics in molecules. We are reporting here a theoretical description of an attosecond pump-probe experiment on CF4 molecule showing clear evidences of a complex dynamics due to ultrafast charge fluctuations.

Since the first experimental demonstration of attosecond (as) pulses in 2001 [1], many progresses have been achieved in attosecond technology. In particular, it is now possible to control electron dynamics in atoms, diatomic molecules [2] and polyatomic molecules [3]. A widely used approach to perform such time-resolved studies is the attosecond pump-probe spectroscopy. It consists in analyzing the response of the atom/molecule interacting with two pulses: a pump pulse (generally an attosecond XUV pulse generated by high-harmonic generation) and a probe pulse (IR, VIS, XUV, or X-ray) used to probe the dynamics generated by the former pulse. The temporal information is acquired by varying the time-delay between the two pulses.

In this work, we present the results of a theoretical simulation of an attosecond pump-probe experiment on CF4 with two collinear pulses. A 150 as XUV pump pulse centered at 33 eV ionizes the molecule, ejecting an electron from different molecular orbitals, followed by a time-delayed 3.6 fs VIS pulse (3.2 eV). The laser intensities, 2×1011 and 2×1012 W/cm2 respectively, are weak enough to avoid the distortion of the molecular potential.

The theoretical methodology consists in solving the time-dependent Schrödinger equation in a basis of Kohn-Sham orbitals and using the exclusive probability formalism to include interchannel couplings [4]. The basis is obtained in the dipole, fixed-nuclei and static-exchange approximations by solving the Kohn-Sham Hamiltonian using a B-spline multicenter approach and the LB94 functional.

Figure 1 shows the photoelectron spectra leaving the ion in four different states. In all cases, the photoelectron spectra due to the XUV pump only has been subtracted in order to increase visibility. The four spectra present oscillations with two different behaviors: in the region of overlapping pulses (τ < 2.5 fs), the oscillations are approximately twice the frequency of the VIS probe pulse ; for higher time-delays, the oscillations present different frequencies (5.8 eV for 4a1 and 1e1 and 5.4 eV for 1t1 and 3t2), indicating an ultrafast charge dynamics beating between the CF4

+(4a1-1) and CF4

+(1e1-1) states and between CF4

+(1t1-1) and CF4

+(3t2-1) states.

Figure 1: Theoretical pump-probe photoelectron spectra of two photoionization channels of CF4.

Notes and References

[1] P. M. Paul et al. 2001 Science, 292, 1689 [3] F. Calegari 2014 Science, 346, 336 [2] G. Sansone et al. 2010 Nature, 465, 763 [4] E. Plésiat 2018, Chem. Eur. J. 24, 12061

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ORAL Conservation of Torus-Knot Angular Momentum in High-

Harmonic Generation Driven by Fields with Spin-Orbit Mixing Emilio Pisanty,*a Carlos Hernández-García,b Laura Rego,b Antonio Picón, a,c Julio San

Román,b Gerard J. Machado,a Verónica Vicuña, a Alessio Celi,a,d Kevin M. Dorney, d Henry C. Kapteyn,e Margaret M. Murnane,e Juan P. Torres,a,f Luis Plajab and Maciej Lewensteina,g

a ICFO – Institut de Ciences Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona) b Departamento de Física Aplicada, University of Salamanca, E-37008, Salamanca, Spain c Departamento de Química, Universidad Autónoma de Madrid, 28049, Madrid, Spain d University of Innsbruck and Austrian Academy of Sciences, Innsbruck, Austria; Universitat Autònoma de Barcelona, Bellaterra, Spain e JILA, Department of Physics, University of Colorado Boulder, Boulder, Colorado, 80309, USA f Department of Signal Theory and Communications, Universitat Politecnica de Catalunya, Barcelona, Spain g ICREA, Passeig de Lluís Companys, 23, 08010 Barcelona, Spain

E-mail: [email protected] High-harmonic generation, as a non-perturbative nonlinear process, has been shown to conserve energy, momentum, and spin and orbital angular momentum, but the symmetries that correspond to these conserved quantities can often be combined in nontrivial ways to produce new transformations. This is the case, in particular, for coordinated rotations, which combine a rotation of the spatial dependence by an angle α with a rotation of the polarization by a fraction #% of that angle. Here # is a coordination parameter, and it is typically restricted – for monochromatic light – to integer or half-integer values.

In this work we show that a wider class of geometries is available with bichromatic drivers, whose more varied internal symmetries allow for arbitrary rational values of #, and this in turn endows the driving field with the topology of a torus knot [1]. Moreover, if those fields are used to produce high-order harmonics, giving the system a dynamical symmetry of the form

& #% ' & % ()*, , = ' *, , + %/ , (1)

the resulting harmonics then form interlinked spirals of attosecond pulses, and each pulse carries a linear polarization which rotates by a fraction γ of a revolution per winding of the spiral. When seen in the frequency domain, this implies that the generator for the symmetry transformation (the torus-knot angular momentum, TKAM, defined as 01 =2 + #3) is conserved in the nonlinear interaction [2]. Moreover, the nontrivial topology of the drivers is up-converted and transmitted to the harmonic emission.

This configuration, coupling OAM and spin, allows for bright XUV beams carrying tunable OAM, with the TKAM symmetry providing the correct framework for understanding the emission. More broadly, these beams provide a unique opportunity to probe the interaction of optical topology with extreme nonlinear optics.

Fig. 1: Combining bicircular drivers with OAM produces drivers with a torus-knot topology, where following a trefoil around the beam returns it with a 120° rotation. The harmonic emission then forms attosecond-pulse spirals, whose polarization steadily rotates at a non-integer rate.

References 1 Pisanty, E., et al. Nature Photonics 13, 569 (2019) 2 Pisanty, E., et al. Physical Review Letters 122, 203201 (2019)

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ORAL Conservation of Torus-Knot Angular Momentum in High-

Harmonic Generation Driven by Fields with Spin-Orbit Mixing Emilio Pisanty,*a Carlos Hernández-García,b Laura Rego,b Antonio Picón, a,c Julio San

Román,b Gerard J. Machado,a Verónica Vicuña, a Alessio Celi,a,d Kevin M. Dorney, d Henry C. Kapteyn,e Margaret M. Murnane,e Juan P. Torres,a,f Luis Plajab and Maciej Lewensteina,g

a ICFO – Institut de Ciences Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona) b Departamento de Física Aplicada, University of Salamanca, E-37008, Salamanca, Spain c Departamento de Química, Universidad Autónoma de Madrid, 28049, Madrid, Spain d University of Innsbruck and Austrian Academy of Sciences, Innsbruck, Austria; Universitat Autònoma de Barcelona, Bellaterra, Spain e JILA, Department of Physics, University of Colorado Boulder, Boulder, Colorado, 80309, USA f Department of Signal Theory and Communications, Universitat Politecnica de Catalunya, Barcelona, Spain g ICREA, Passeig de Lluís Companys, 23, 08010 Barcelona, Spain

E-mail: [email protected] High-harmonic generation, as a non-perturbative nonlinear process, has been shown to conserve energy, momentum, and spin and orbital angular momentum, but the symmetries that correspond to these conserved quantities can often be combined in nontrivial ways to produce new transformations. This is the case, in particular, for coordinated rotations, which combine a rotation of the spatial dependence by an angle α with a rotation of the polarization by a fraction #% of that angle. Here # is a coordination parameter, and it is typically restricted – for monochromatic light – to integer or half-integer values.

In this work we show that a wider class of geometries is available with bichromatic drivers, whose more varied internal symmetries allow for arbitrary rational values of #, and this in turn endows the driving field with the topology of a torus knot [1]. Moreover, if those fields are used to produce high-order harmonics, giving the system a dynamical symmetry of the form

& #% ' & % ()*, , = ' *, , + %/ , (1)

the resulting harmonics then form interlinked spirals of attosecond pulses, and each pulse carries a linear polarization which rotates by a fraction γ of a revolution per winding of the spiral. When seen in the frequency domain, this implies that the generator for the symmetry transformation (the torus-knot angular momentum, TKAM, defined as 01 =2 + #3) is conserved in the nonlinear interaction [2]. Moreover, the nontrivial topology of the drivers is up-converted and transmitted to the harmonic emission.

This configuration, coupling OAM and spin, allows for bright XUV beams carrying tunable OAM, with the TKAM symmetry providing the correct framework for understanding the emission. More broadly, these beams provide a unique opportunity to probe the interaction of optical topology with extreme nonlinear optics.

Fig. 1: Combining bicircular drivers with OAM produces drivers with a torus-knot topology, where following a trefoil around the beam returns it with a 120° rotation. The harmonic emission then forms attosecond-pulse spirals, whose polarization steadily rotates at a non-integer rate.

References 1 Pisanty, E., et al. Nature Photonics 13, 569 (2019) 2 Pisanty, E., et al. Physical Review Letters 122, 203201 (2019)

ORAL Topological strong field physics on sub-laser cycle timescale Álvaro Jiménez-Galán,*a Rui Silva,b Bruno Amorim, c Olga Smirnovaa,d and Misha Ivanova,e,f

aMax Born Institut, Max Born Strasse 2A, D-12489 Berlin, Germany; bDepartment of Theoretical Condensed Matter Physics, Universidad Autónoma de Madrid, E-28048, Madrid, Spain; cCeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; dTechnische Universität Berlin, Ernst Ruska Gebäude, Hardenbergstraße 36A, 10623 Berlin, Germany; eDepartment of Physics, Humboldt University, Newtonstraße 15, D-12489 Berlin, Germany; fBlackett Laboratory, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom;


Quantum materials encompass a rich variety of systems with fascinating features. One of them is the topological phase transition, upon which an insulator becomes conducting, supporting robust currents around its edges [1]. “Protected” by the topological invariants of the bulk, the chiral edge states are robust to perturbations, making them appealing for technological applications. However, and surprisingly, the ultrafast dynamics of non-equilibrium electronic response to intense optical fields in these materials has remained virtually unexplored. Yet, understanding these dynamics is not only fundamentally interesting. It is also crucial for light-wave electronics in topological materials.

Attosecond science has made major progress in understanding ultrafast electron dynamics in solids [2]. Yet, so far it has mostly focused on the role of the band structure. The role of fundamental properties of novel quantum materials, such as the Berry curvature or the topological invariants, on the attosecond dynamics of electronic response has been hardly explored. Does the highly non-equilibrium electron dynamics in the bulk, driven by a strong laser field, encode the system’s topological properties on the sub-laser cycle time-scale? How does the Berry curvature affect the field-driven injection of electrons across the bandgap?

In this work, we answer these questions using the paradigmatic example of the topological insulator, the Haldane system [3]. We show how topological effects can be identified on the directionality and the attosecond timing of an electron current injected into the conduction band by the oscillating electric field of an intense pulse. We further show that the high harmonic emission displays topologically-dependent attosecond delays, and that the helicities of the emitted harmonics can record the topological phase diagram of the system [4].

Figure 1. The helicity of the high harmonics (blue for right-circularly polarized light, red for left-circularly polarized) maps the phase diagram of Chern insulators. The blue solid line marks the topological phase transition, separating the trivial phase (above) from the topological phase (below). Notes and References 1 Hasan, M.Z.; Kane, C.L. Rev. Mod. Phys. 2010 82 3045 2 Kruchinin, S.Y.; Krausz, F.; Yakovlev, V.S. Rev. Mod. Phys. 2018 90 021002 3 Haldane, F.D.M. Phys. Rev. Lett. 1988 61 2015 4 Silva, R.E.F.; Jiménez-Galán, Á.; Amorim, B.; Smirnova, O.; Ivanov, M. Nat. Phot. 2019 accepted

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INVITED Ultrafast interference dynamics of polariton condensates

Elena Rozasa,b, Carlos Antónc, Pavlos Savvidisd, Sven Höflinge, Luis Viñaa,b,f, Dolores Martína,b

aDepartamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid, Spain bInstituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain cCentre de Nanosciences et de Nanotechnologies (C2N-CNRS), 91120 Palaiseau, France dFORTH-IESL, P.O. Box 1385, 71110 Heraklion, Crete, Greece eLehrstuhl für Technische Physik, University of Würzburg, Würzburg 97074, Germany fInstituto de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain

E-mail: [email protected] In the last decade, a condensed matter version of Bose – Einstein condensation (BEC) has been achieved using semiconductor microcavities [1]. In these systems, the strong radiation – matter interaction leads to the formation of new quasi – particles (polaritons), which condense at cryogenic temperatures. This condensation opens up the way for the development of polariton – based devices with ultrafast switching times, low losses and low power consumption [2].

Additionally, semiconductor microcavities provide an outstanding setting to address fundamental quantum mechanical questions as, for example, the relative phase of two distant components of a condensate [3]. We use simultaneous real – and Fourier – space interferometry to study ultrafast coherence phenomena in polariton condensates. We obtain fringes in reciprocal space as a result of the interference between polariton condensates traveling with the same speed. Like this we are able to avoid any spatial overlap between two parts of a macroscopic quantum state. The periodicity of the fringes is inversely proportional to the spatial distance between the interfering condensates. Similarly, we obtain interference fringes in real space when condensates traveling in opposite directions meet [4]. We have performed a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates [5]. The visibility of both real – and reciprocal – space interference fringes rapidly decreases with increasing temperature and vanishes. A comparison with theories developed for atomic

condensates, which consider the coexistence of condensed and noncondensed particles, allows us to infer a critical temperature for the BEC – like transition when the visibility goes to zero.

Figure 1.- (a/b) Emission measured in real/reciprocal space. Gray circles (x=±35 μm) indicate the spatial location of A and B laser beams; the trajectories of the 4 condensates (nA

1, nA2, nB

1, nB2) are indicated by the dashed arrows.

References 1 J. Kasprzak, et al., Nature 443, 409 (2006). 2 C. Antón, et al., Appl. Phys. Lett. 101, 261116 (2012). 3 P. W. Anderson, Basic Notions of Condensed Matter Physics (Benjamin, 1984). 4 C. Antón, et al., Phys. Rev. B 90, 081407(R) (2014). 5 E. Rozas, et al., Phys. Rev. B 97, 075442 (2018).

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INVITED Ultrafast interference dynamics of polariton condensates

Elena Rozasa,b, Carlos Antónc, Pavlos Savvidisd, Sven Höflinge, Luis Viñaa,b,f, Dolores Martína,b

aDepartamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid, Spain bInstituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain cCentre de Nanosciences et de Nanotechnologies (C2N-CNRS), 91120 Palaiseau, France dFORTH-IESL, P.O. Box 1385, 71110 Heraklion, Crete, Greece eLehrstuhl für Technische Physik, University of Würzburg, Würzburg 97074, Germany fInstituto de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain

E-mail: [email protected] In the last decade, a condensed matter version of Bose – Einstein condensation (BEC) has been achieved using semiconductor microcavities [1]. In these systems, the strong radiation – matter interaction leads to the formation of new quasi – particles (polaritons), which condense at cryogenic temperatures. This condensation opens up the way for the development of polariton – based devices with ultrafast switching times, low losses and low power consumption [2].

Additionally, semiconductor microcavities provide an outstanding setting to address fundamental quantum mechanical questions as, for example, the relative phase of two distant components of a condensate [3]. We use simultaneous real – and Fourier – space interferometry to study ultrafast coherence phenomena in polariton condensates. We obtain fringes in reciprocal space as a result of the interference between polariton condensates traveling with the same speed. Like this we are able to avoid any spatial overlap between two parts of a macroscopic quantum state. The periodicity of the fringes is inversely proportional to the spatial distance between the interfering condensates. Similarly, we obtain interference fringes in real space when condensates traveling in opposite directions meet [4]. We have performed a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates [5]. The visibility of both real – and reciprocal – space interference fringes rapidly decreases with increasing temperature and vanishes. A comparison with theories developed for atomic

condensates, which consider the coexistence of condensed and noncondensed particles, allows us to infer a critical temperature for the BEC – like transition when the visibility goes to zero.

Figure 1.- (a/b) Emission measured in real/reciprocal space. Gray circles (x=±35 μm) indicate the spatial location of A and B laser beams; the trajectories of the 4 condensates (nA

1, nA2, nB

1, nB2) are indicated by the dashed arrows.

References 1 J. Kasprzak, et al., Nature 443, 409 (2006). 2 C. Antón, et al., Appl. Phys. Lett. 101, 261116 (2012). 3 P. W. Anderson, Basic Notions of Condensed Matter Physics (Benjamin, 1984). 4 C. Antón, et al., Phys. Rev. B 90, 081407(R) (2014). 5 E. Rozas, et al., Phys. Rev. B 97, 075442 (2018).

INVITED Ultrafast coupled photonic, electronic, and nuclear dynamics

in molecular polaritons Johannes Feist

Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Spain

E-mail: [email protected] It is well-known that strong laser fields can be used to modify and engineer molecular dynamics and potential energy surfaces. However, over the last years, it has become clear that similar goals can also be achieved even when no actual light is present in the system by engineering the electromagnetic vacuum and its fluctuations, based on quantum electrodynamics. One powerful tool to achieve such modifications is strong coupling, which occurs when the coherent energy exchange between a (confined) light mode in an optical cavity and material excitations becomes faster than the decay and decoherence of either constituent. This creates a paradigmatic hybrid quantum system with eigenstates that have mixed light-matter character, so-called polaritons. Organic molecules present a particularly favorable type of emitter to achieve this regime even at room temperature due to their large dipole moments and stability. Polariton formation then leads to changes in the excited-state character and energy levels (i.e., potential energy surfaces), which can affect a wide range of properties, such as energy transport, photochemical reactions, and even thermally driven ground-state chemical reactions. At the same time, such systems display ultrafast femtosecond-scale dynamics in their coupled photonic, electronic, and nuclear degrees of freedom. I will discuss ways to observe and manipulate these dynamics, based on two separate numerical approaches: a quantum mechanics / molecular mechanics (QM/MM) simulation that includes quantized light modes and is able to represent the full chemical complexity of the molecules [1], and a tensor-network-based approached that allows a full quantum simulation of all degrees of freedom, including the nuclei [2].

In particular, we exploit the peculiar properties of hybrid light-matter states in plasmonic nanocavities to propose a polaritonic molecular clock that allows all-optical ultrafast imaging of wavepacket dynamics without probe pulses. Conventional approaches to probing ultrafast molecular dynamics rely on the use of synchronized laser pulses with a well-defined time delay, where typically, a pump pulse excites a wavepacket in the molecule. A subsequent probe pulse then dissociates or ionizes the molecule, and measurement of the molecular fragments provides information about where the wavepacket was for each time delay. We propose to instead exploit the ultrafast nuclear-position-dependent emission obtained due to large light-matter coupling in plasmonic nanocavities to image wavepacket dynamics using only a single pump pulse. We show that the time-resolved emission from the cavity provides information about when the wavepacket passes a given region in nuclear configuration space. This approach can image both cavity-modified dynamics on polaritonic (hybrid light-matter) potentials in the strong light-matter coupling

regime as well as bare-molecule dynamics in the intermediate coupling regime of large Purcell enhancements, and provides a new route towards ultrafast molecular spectroscopy with plasmonic nanocavities.

Figure: Nuclear wavepacket motion on a polaritonic potential energy surface after excitation by a few-femtosecond pulse. The upper panel shows the ultrafast time-resolved photon emission intensity (thick blue line) and the probability for the wavepacket to be in the spatial region q<0 (thin orange line). Measuring the emitted field can thus provide an all-optical probe of nuclear wavepacket motion without the need of a

separate pulse to interrogate the dynamics.

References 1 G. Groenhof, C. Climent, J. Feist, D. Morozov, J. J. Toppari, J. Phys. Chem. Lett., 2019, 10.1021/acs.jpclett.9b02192 2 J. del Pino, F. A. Y. N. Schröder, A. W. Chin, J. Feist, F. J. Garcia-Vidal, Phys. Rev. Lett., 2018, 121, 227401. 3 R. E. F. Silva, J. del Pino, F. J. García-Vidal, J. Feist, arXiv:1907.12607.

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INVITED Lifetimes, Photostability and other Photophysical Aspects of

Life-Related Molecules Iker Lamas,a Raúl Montero,b Lluis Blancafort,c Asier Longarte*a

aDepartamento de Química Física. Universidad del País Vasco (UPV/EHU). Apart. 644, 48080 Bilbao, Spain bSGIKER Laser Facility. Universidad del País Vasco (UPV/EHU). Leioa, Spain cInstitut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain


There is a close relation between nucleobases, the so called life building blocks, and solar UV radiation. The response that these compounds exhibit to electronic excitation is thought to have played a key role in their election as life supporting molecules.1 Consequently, in order to understand the evolution from prebiotic life to the actual life-related molecules is mandatory to know the electronic relaxation mechanisms of simpler models that can serve as a guide to the photophysics/photochemistry of more complex systems.2 Herein, we present an experimental study on the excited state dynamics of a set of Azaindole structural isomers. The collected data, suported by the prediction of ab initio calculations, have allowed us to identify the operative relaxation pathways. The implications of the obtained results for related biological molecules will be discussed.

FIGURE. Decay of 6-Azaindole after electronic excitation at 292 nm.

References 1 Beckstead, A. A.; Zhang, Y.; de Vries, M. S.; Kohler, B. Phys. Chem. Chem. Phys. 2016, 18, 24228. 2 Marchetti, B.; Karsili, T. N. V.; Ashfold, M. N. R.; Domcke, W. Phys. Chem. Chem. Phys. 2016, 18, 20007.

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INVITED Lifetimes, Photostability and other Photophysical Aspects of

Life-Related Molecules Iker Lamas,a Raúl Montero,b Lluis Blancafort,c Asier Longarte*a

aDepartamento de Química Física. Universidad del País Vasco (UPV/EHU). Apart. 644, 48080 Bilbao, Spain bSGIKER Laser Facility. Universidad del País Vasco (UPV/EHU). Leioa, Spain cInstitut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain


There is a close relation between nucleobases, the so called life building blocks, and solar UV radiation. The response that these compounds exhibit to electronic excitation is thought to have played a key role in their election as life supporting molecules.1 Consequently, in order to understand the evolution from prebiotic life to the actual life-related molecules is mandatory to know the electronic relaxation mechanisms of simpler models that can serve as a guide to the photophysics/photochemistry of more complex systems.2 Herein, we present an experimental study on the excited state dynamics of a set of Azaindole structural isomers. The collected data, suported by the prediction of ab initio calculations, have allowed us to identify the operative relaxation pathways. The implications of the obtained results for related biological molecules will be discussed.

FIGURE. Decay of 6-Azaindole after electronic excitation at 292 nm.

References 1 Beckstead, A. A.; Zhang, Y.; de Vries, M. S.; Kohler, B. Phys. Chem. Chem. Phys. 2016, 18, 24228. 2 Marchetti, B.; Karsili, T. N. V.; Ashfold, M. N. R.; Domcke, W. Phys. Chem. Chem. Phys. 2016, 18, 20007.

ORAL

Temporal jitter stabilisation of SwissFEL

Christopher Arrella and the SwissFEL team

aLaboratory for Advanced Photonics, Paul Scherrer Institut, Villigen, 5232, Switzerland


User operation began at SwissFEL in January 2019 utilising the Alvra and Bernina endstations1. Time resolved user experiments have had available diagnostic tools to measure the jitter between the FEL and pump laser pulse using either refractive index based time tools2 or photoelectron streaking time tools3. Reported here is the measured ~ 80 fs (FWHM) jitter between the FEL and pump laser systems. The performance of the time tools is reported including the correlation between the photoelectron streaking and refractive index based tools. These tools are used to stabilise the longer term drift between pump laser and FEL to within 10 fs over a week period.

To complement the hard X-ray branch of SwissFEL (Aramis), a soft X-ray FEL (Athos) is due to lase in December 2019. The outlook for time resolved measurements at the two endstations for AMO and condensed matter physics will be discussed.

Figure a) Correlation between spatial time tool data vs THz streaking data. b) Histogram of spatial time tool - THz streaking a sigma of 10 fs. c) Bi 111 phonon oscillations probed with 9 keV with and without spatial time tool correction.

Notes and References 1. Milne, C. J. et al. SwissFEL: The Swiss X-ray Free Electron Laser. Appl. Sci. 7, 720 (2017). 2. Harmand, M. et al. Achieving few-femtosecond time-sorting at hard X-ray free-electron lasers. Nat. Photonics 7, 215–218

(2013). 3. Frühling, U. Light-field streaking for FELs. J. Phys. B At. Mol. Opt. Phys. 44, 243001 (2011).

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ORAL Photoionization dynamics in simple molecules: the case of H2,

CO and N2O Laura Cattaneo,*a and Ursula Kellera

aPhysics Department, ETH Zurich, 8093 Zurich, Switzerland E-mail: [email protected]

Up to now, the observation of photoionization time delays in molecules has been limited to only a few experimental studies [1-3] mostly due to their intrinsic complexity which makes “clean” and “complete” measurements very challenging. We report the investigation of three different cases: H2, CO and N2O, highlighting in each of them a specific aspect of their molecular nature and confirming the paramount importance of angular resolution and electron-ion coincidence detection towards the complete understanding of more complex systems. In particular, in H2 [4] we obtained the first experimental evidence of the importance of the coupled electron-nuclear motion for the attosecond ionization dynamics confirmed by a complete ab initio theoretical study with the group of Fernando Martín (see Fig. 1a). The study in CO [5], with an asymmetric Coulomb potential, revealed that the accumulated phase of the escaping electron wave packet is not only energy- and molecular orientation dependent, but can give insight into the mean position of the ionization within the CO molecular potential (see Fig. 1b). This dependence is unique to the molecular photoionization process and has been supported by two different theoretical models by S. Patchkovskii’s and A. Landsman’s groups. We introduced the Stereo-Wigner Time Delay (SWTD) which is the time delay difference between two escaping electrons on opposite sides of the molecule. The unexpected highly negative SWTD can be explained by the localization of the electron within the molecular frame right at the beginning of the electron escape dynamics. Finally we exploited angular-resolved attosecond measurements in N2O molecules to reveal new physical insights into the phenomenon of shape resonances (SR) in molecules: a heavily discussed topic in the field of molecular spec-troscopy that is still not completely clarified [6]. It has been recently shown by Huppert et al. that SR can induce photoionization delays up to ~160 as in N2O [2]. In particular we inspected the dependence of the photoionization time delays on the photoelectron emission angle mapping the internal molecular potential (see Fig. 1c). This study is theoretically supported using quantum scattering methods provided by the group of Prof. H. J. Wörner [7]. All these investigations have been carried out exploiting the XUV pump/IR probe RABBITT interferometric technique combined with a coincidence detection using a COLTRIMS apparatus [8, 9].

Figure 1: a) 3D maps of the experimental photoelectron phases in H2 as a function of both the electron and the nuclear kinetic energy (KER); b) mean position of the electron localization at the instant of birth into the continuum of CO as a function of the electron kinetic energy; c) Angular resolved analysis of photoemitted electrons in N2O as a function of the electron kinetic energy.


1 Haessler, S.; Fabre, B.; Higuet, J., et al., Phys Rev A 2009,80 2 Huppert, M.; Jordan, I.; Baykusheva, D., et al., Phys Rev Lett 2016,117,093001 3 Sansone, G.; Kelkensberg, F.; Perez-Torres, J.F., et al., Nature 2010,465,763-U763 4 Cattaneo, L.; Vos, J.; Bello, R.Y., et al., Nat Phys 2018,14,733-738 5 Vos, J.; Cattaneo, L.; Patchkovskii, S., et al., Science 2018,360,1326-1330 6 Piancastelli, M.N., J Electron Spectrosc 1999,100,167-190 7 Baykusheva, D. and Worner, H.J., J Chem Phys 2017,146 8 Dörner, R., Mergel, V., Jagutzki, O., et al., Phys. Rep. 2000,330,95-192 9 Sabbar, M.; Heuser, S.; Boge, R., et al., Review of Scientific Instruments 2014,85

b)a) c)

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ORAL Photoionization dynamics in simple molecules: the case of H2,

CO and N2O Laura Cattaneo,*a and Ursula Kellera

aPhysics Department, ETH Zurich, 8093 Zurich, Switzerland E-mail: [email protected]

Up to now, the observation of photoionization time delays in molecules has been limited to only a few experimental studies [1-3] mostly due to their intrinsic complexity which makes “clean” and “complete” measurements very challenging. We report the investigation of three different cases: H2, CO and N2O, highlighting in each of them a specific aspect of their molecular nature and confirming the paramount importance of angular resolution and electron-ion coincidence detection towards the complete understanding of more complex systems. In particular, in H2 [4] we obtained the first experimental evidence of the importance of the coupled electron-nuclear motion for the attosecond ionization dynamics confirmed by a complete ab initio theoretical study with the group of Fernando Martín (see Fig. 1a). The study in CO [5], with an asymmetric Coulomb potential, revealed that the accumulated phase of the escaping electron wave packet is not only energy- and molecular orientation dependent, but can give insight into the mean position of the ionization within the CO molecular potential (see Fig. 1b). This dependence is unique to the molecular photoionization process and has been supported by two different theoretical models by S. Patchkovskii’s and A. Landsman’s groups. We introduced the Stereo-Wigner Time Delay (SWTD) which is the time delay difference between two escaping electrons on opposite sides of the molecule. The unexpected highly negative SWTD can be explained by the localization of the electron within the molecular frame right at the beginning of the electron escape dynamics. Finally we exploited angular-resolved attosecond measurements in N2O molecules to reveal new physical insights into the phenomenon of shape resonances (SR) in molecules: a heavily discussed topic in the field of molecular spec-troscopy that is still not completely clarified [6]. It has been recently shown by Huppert et al. that SR can induce photoionization delays up to ~160 as in N2O [2]. In particular we inspected the dependence of the photoionization time delays on the photoelectron emission angle mapping the internal molecular potential (see Fig. 1c). This study is theoretically supported using quantum scattering methods provided by the group of Prof. H. J. Wörner [7]. All these investigations have been carried out exploiting the XUV pump/IR probe RABBITT interferometric technique combined with a coincidence detection using a COLTRIMS apparatus [8, 9].

Figure 1: a) 3D maps of the experimental photoelectron phases in H2 as a function of both the electron and the nuclear kinetic energy (KER); b) mean position of the electron localization at the instant of birth into the continuum of CO as a function of the electron kinetic energy; c) Angular resolved analysis of photoemitted electrons in N2O as a function of the electron kinetic energy.


1 Haessler, S.; Fabre, B.; Higuet, J., et al., Phys Rev A 2009,80 2 Huppert, M.; Jordan, I.; Baykusheva, D., et al., Phys Rev Lett 2016,117,093001 3 Sansone, G.; Kelkensberg, F.; Perez-Torres, J.F., et al., Nature 2010,465,763-U763 4 Cattaneo, L.; Vos, J.; Bello, R.Y., et al., Nat Phys 2018,14,733-738 5 Vos, J.; Cattaneo, L.; Patchkovskii, S., et al., Science 2018,360,1326-1330 6 Piancastelli, M.N., J Electron Spectrosc 1999,100,167-190 7 Baykusheva, D. and Worner, H.J., J Chem Phys 2017,146 8 Dörner, R., Mergel, V., Jagutzki, O., et al., Phys. Rep. 2000,330,95-192 9 Sabbar, M.; Heuser, S.; Boge, R., et al., Review of Scientific Instruments 2014,85

b)a) c)

ORAL

Generation of high energy laser-driven electron and proton sources with the 200 TW system VEGA 2 at the Centro de

Láseres Pulsados

Jose A. Pérez-Hernández,*a Luca Volpe,a,b Robert Fedosejevs,c Giancarlo Gatti,a Cruz Méndez,a Jon Apiñaniz,a Xavier Vaisseau,a Carlos Salgado,a Marine Hault,a Sophia Malko,a

Ghassan Zeraouli,a Valeria Ospina,a Andrew Longman,c Diego de Luis,a Massimo de Marco,a Kun Li,a Oscar Varela,a Enrique García,a Irene Hernández,a José David Pisonero,a Javier

García Ajates,a José Manuel Álvarez,a Cristina García,a Mauricio Rico,a Diego Arana,a Juan Hernández-Toro, a and Luis Rosoa,d

aCentro de Láseres Pulsados (CLPU), Edificio M5. Parque Científico, C/ Adaja, 8, 37185, Villamayor, Salamanca, Spain; bLaser Plasma Chair at the University of Salamanca, Salamanca, Spain; cDepartment of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4, Canada; dUniversity of Salamanca, Salamanca, Spain; E-mail: [email protected] The Centro de Láseres Pulsados in Salamanca, Spain has recently started operation phase and the first user access period on the 6 J 30 fs 200 TW system (VEGA 2) already started at the beginning of 2018. In this paper we report on two commissioning experiments recently performed on the VEGA 2 system. VEGA 2 system has been tested in different configurations depending on the focusing optics and targets used. One configuration (long focal length F = 130 cm) is for underdense laser–matter interaction where VEGA 2 is focused onto a low density gas-jet generating electron beams (via laser wakefield acceleration mechanism) with maximum energy up to 500 MeV and an X-ray betatron source with a 10 keV critical energy. A second configuration (short focal length F = 40 cm) is for overdense laser–matter interaction where VEGA 2 is focused onto a 5 μm thick Al target generating a proton beam with a maximum energy of 10 MeV and temperature of 2.5 MeV.

.

Fig.1 Long focal experimental set-up at VEGA 2 system

References 1 Volpe, L. et al. High Power Laser Science and Engineering 2019, Vol 7, E25

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PLENARY Attosecond molecular physics: investigation and control of

ultrafast processes in bio-relevant molecules Mauro Nisoli

Politecnico di Milano, Department of Physics, Piazza Leonardo da Vinci 32, 20133 Milano, Italy. Tel: +39 0223996167; E-mail: [email protected]

The investigation of ultrafast processes initiated in molecules by light absorption is of crucial importance in various research areas, from molecular physics to chemistry and biology, from material science to technological applications [1]. At a fundamental level, the time scale relevant for ultrafast processes at the atomic or molecular level is set by the motion of electrons, which occurs on ultrashort time scales. In the last few years, the use of attosecond pulses in the extreme-ultraviolet (EUV) spectral region has demonstrated to be a very powerful experimental tool for the investigation of physical processes evolving in molecules on time scales ranging from a few femtoseconds down to tens of attoseconds.

I will discuss how the use of attosecond techniques enabled the investigation of a number of crucial processes in complex molecules evolving on different time scales. I will mainly concentrate on biologically-relevant molecules. The measurement of charge migration in amino acids [2] has triggered the investigation of electronic coherences [3] and correlation effects [4] in molecular structures. Attosecond techniques has been implemented for the investigation of photostability and radiation damage in a DNA building block (the nucleic-acidbaseadenine) and has led to the identification of a robust and simple stabilisation mechanism based on a many body effect in a DNA base, where adding energy to the system actually opens a non-dissociative relaxation path [5]. Intramolecular hydrogen migration in glycine has been measured [6], which is particularly interesting since it may lead to oxidative damage of a peptide.

The application of attosecond techniques to molecular physics has opened new research frontiers. Experimental advances, in terms of new sources, devices and techniques, are still required, together with new theoretical tools and approaches, but attosecond molecular physics has firmly established as a mature research field.

Notes and References 1 Nisoli, M.; Decleva, P.; Calegari, F.; Palacios, A.;. Martín, F. Chem. Reviews 2017, 117, 10760-10825 2 Calegari, F.; Ayuso, D.; Trabattoni, A.; Belshaw, L.; De Camillis, S.; Anumula, S.; Frassetto, F.; Poletto, L.; Palacios, A.; Decleva, P.;

Greenwood, J.; Martín, F.; Nisoli, M. Science 2014, 346, 336-339 3 Lara-Astiaso, M.; Galli, M.; Trabattoni, A.; Palacios, A.; Ayuso, D.; Frassetto, F.; Poletto, L.; De Camillis, S.; Greenwood, J.; Decleva,

P.; Tavernelli, I.; Calegari, F.; Nisoli, M.; Martín F. J. Phys. Chem. Lett. 2018, 9, 4570-4577 4 Perfetto, E.; Sangalli, D.; Marini, A.; Stefanucci, G. J. Phys. Chem. Lett. 2018, 9, 1353-1358 5 Latini, S.; Månsson, E.P.; Galli, M.; Wanie, V.; Covito, F.; Perfetto, E.; Stefanucci, G.; Hübener, H.; De Giovannini, U.; Castrovilli,

M.C.; Trabattoni, A.; Frassetto, F.; Poletto, L.; Greenwood, J.; Légaré, F.; Nisoli, M.; Rubio, A.; Calegari, F. “Ultrafast laser-assisted stabilization of ionized adenine,” 7th International Conference on Attosecond Science and Technology – ATTO2019 (1-5 July 2019, Szeged, Hungary)

6 Castrovilli, M.C.; Trabattoni, A.; Bolognesi, P.; O’Keeffe, P.; Avaldi, L.; Nisoli, M.; Calegari, F.; Cireasa, R. J. Phys. Chem. Lett. 2018, 9, 6012-6016

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PLENARY Attosecond molecular physics: investigation and control of

ultrafast processes in bio-relevant molecules Mauro Nisoli

Politecnico di Milano, Department of Physics, Piazza Leonardo da Vinci 32, 20133 Milano, Italy. Tel: +39 0223996167; E-mail: [email protected]

The investigation of ultrafast processes initiated in molecules by light absorption is of crucial importance in various research areas, from molecular physics to chemistry and biology, from material science to technological applications [1]. At a fundamental level, the time scale relevant for ultrafast processes at the atomic or molecular level is set by the motion of electrons, which occurs on ultrashort time scales. In the last few years, the use of attosecond pulses in the extreme-ultraviolet (EUV) spectral region has demonstrated to be a very powerful experimental tool for the investigation of physical processes evolving in molecules on time scales ranging from a few femtoseconds down to tens of attoseconds.

I will discuss how the use of attosecond techniques enabled the investigation of a number of crucial processes in complex molecules evolving on different time scales. I will mainly concentrate on biologically-relevant molecules. The measurement of charge migration in amino acids [2] has triggered the investigation of electronic coherences [3] and correlation effects [4] in molecular structures. Attosecond techniques has been implemented for the investigation of photostability and radiation damage in a DNA building block (the nucleic-acidbaseadenine) and has led to the identification of a robust and simple stabilisation mechanism based on a many body effect in a DNA base, where adding energy to the system actually opens a non-dissociative relaxation path [5]. Intramolecular hydrogen migration in glycine has been measured [6], which is particularly interesting since it may lead to oxidative damage of a peptide.

The application of attosecond techniques to molecular physics has opened new research frontiers. Experimental advances, in terms of new sources, devices and techniques, are still required, together with new theoretical tools and approaches, but attosecond molecular physics has firmly established as a mature research field.

Notes and References 1 Nisoli, M.; Decleva, P.; Calegari, F.; Palacios, A.;. Martín, F. Chem. Reviews 2017, 117, 10760-10825 2 Calegari, F.; Ayuso, D.; Trabattoni, A.; Belshaw, L.; De Camillis, S.; Anumula, S.; Frassetto, F.; Poletto, L.; Palacios, A.; Decleva, P.;

Greenwood, J.; Martín, F.; Nisoli, M. Science 2014, 346, 336-339 3 Lara-Astiaso, M.; Galli, M.; Trabattoni, A.; Palacios, A.; Ayuso, D.; Frassetto, F.; Poletto, L.; De Camillis, S.; Greenwood, J.; Decleva,

P.; Tavernelli, I.; Calegari, F.; Nisoli, M.; Martín F. J. Phys. Chem. Lett. 2018, 9, 4570-4577 4 Perfetto, E.; Sangalli, D.; Marini, A.; Stefanucci, G. J. Phys. Chem. Lett. 2018, 9, 1353-1358 5 Latini, S.; Månsson, E.P.; Galli, M.; Wanie, V.; Covito, F.; Perfetto, E.; Stefanucci, G.; Hübener, H.; De Giovannini, U.; Castrovilli,

M.C.; Trabattoni, A.; Frassetto, F.; Poletto, L.; Greenwood, J.; Légaré, F.; Nisoli, M.; Rubio, A.; Calegari, F. “Ultrafast laser-assisted stabilization of ionized adenine,” 7th International Conference on Attosecond Science and Technology – ATTO2019 (1-5 July 2019, Szeged, Hungary)

6 Castrovilli, M.C.; Trabattoni, A.; Bolognesi, P.; O’Keeffe, P.; Avaldi, L.; Nisoli, M.; Calegari, F.; Cireasa, R. J. Phys. Chem. Lett. 2018, 9, 6012-6016

INVITED Evaluation of the tolerance on solid nanostructured targets for

proton laser acceleration M.Blanco, a M.Vranic,b and M.T.Flores-Arias*a

aGrupo Photonics4Life, Departamento de Física Aplicada, Facultade de Fisica, Universidade de Santiago de Compostela, Campus Vida s/n, Santiago de Compostela, E15782, Spain. bGoLP/IPFN, Instituto Superior Tecnico, Universidade de Lisboa, Lisbon, Portugal.

E-mail: [email protected] In the last decades ion acceleration by laser is being evaluated as a promising technology for the future [1,2]. Ions are accelerated into the MeV regime with a table-top laser and a metallic thin foil, via Target Normal Sheath Acceleration (TNSA) [3]. The improvement of the laser absorption when nanostructured solid targets are used and therefore the increase of the accelerated particles energy has been presented [4-5]. To our knowledge, the numerical and theoretical analysis of the TNSA proton acceleration present in the literature regarding the dependence of the laser energy absorption on the nanostructured solid target, always assume perfect nanostructures. Some aspects of the interaction are bound to change when real targets are used, as the fabrication techniques have a limited precision. This work presents how robust the experimental configuration is in terms of deviations on the ideal nanostructures engraved at the surfaces of the solid targets, by using a 2D PIC model.

The setup consist of the STELA laser (Santiago TErawatt LAser), i.e., a Ti:Shappire laser with a peak power of 45TW and contrast >1010 at 5 ps, with an intensity on focus of 3.46x1019 W/cm2 and a solid target with triangular nanostructured on top. For our calculations we depart from a target with the ideal parameters for these triangles, achieving a 97% of the laser energy absorption for proton acceleration with tens of MeV [5]. To analyse the effect of the tolerance of the absorption energy enhancement regarding the irregularities on the periodic nanostructures, we consider targets when each triangle could differ from its immediate neighbours. We simulate a randomly deviation in size for every triangle. The deviation is controlled by a variation percentage, that sets the maximum allowed deviation from the ideal height or width for each triangle (see fig.1).

Figure 1. Examples of targets a) ideally structured with height h and width w; b) where each individual triangle is initialized with a random width deviation up to a maximum of 50%; c) same as in b) but in this case randomly varying the height of each triangle.

The 2D PIC simulations were carried out for four different cases and reveal than when a maximum variation in height is set to the 30% the laser energy absorption decreases to 94.70%, and when a maximum of 60% variation is considered the decreasing goes until 93.96%. If the variation affects to the width of the triangles, the decreasing of the laser energy absorption goes until 93.89% for a maximum variation of 30% and until 94.21% when a maximum variation of 60% is considered.

References 1 A. Macchi, M. Borghesi, and M. Passoni. Rev. Mod.Phys 2013, 85, 751–793. 2 A. Stockem Novo, M. C. Kaluza, R. A. Fonseca, and L. O. Silva. i., 2016, 6, 29402: 1-7. 3 S. C. Wilks, A. B. Langdon, T. E. Cowan, M. Roth, M. Singh, S. Hatchett, M. H. Key, D. Pennington, A. MacKinnon,and R. A.

Snavely. Phys. Plasmas, 2001, 8(2), 542–549. 4 A. Andreev, K. Platonov, J. Braenzel, A. Lübcke, S. Das, H. Messaoudi, R. Grunwald, C. Gray, E. McGlynn, andM. Schnürer.

Plasma Phys. Control. Fusion,58(1):014038, 2016.13. 5 M Blanco, M T Flores-Arias, C Ruiz, and M Vranic. "Table-top laser-based proton acceleration in nanostructuredtargets," New

J. Phys., 19(3):033004, 2017.14

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INVITED TBA

Elisabet Romeroa

a Institute of Chemical Research of Catalonia (ICIQ), Avinguda Països Catalans 16, 43007 Tarragona, Spain

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INVITED TBA

Elisabet Romeroa

a Institute of Chemical Research of Catalonia (ICIQ), Avinguda Països Catalans 16, 43007 Tarragona, Spain

INVITED Bright Future for X-ray Science: European XFEL

Wojciech Gawelda,*a,b

aEuropean XFEL, Holzkoppel 4, 22869 Schenefeld, Germany; bFaculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland;

*E-mail: [email protected] With the advent of soft- and hard X-ray Free Electron Lasers (XFEL) sources, entirely new scientific opportunities and prospects have been become available in the field of structural studies. One of the most unprecedented features of XFELs is their ability to produce high intensity pulsed X-ray beams with single pulse duration well below 100 femtoseconds (1 fs =10-15 s). This property allows dynamical studies of light-matter interactions virtually in any medium on the very fundamental timescales of interatomic motions, i.e. intra- and intermolecular vibrations, from gas-phase to complex strongly correlated solids, i.e. high-temperature superconductors, biomolecules and various nanomaterials. However, this unique feature of XFEL beams permits also to snapshot static structures of nanometer-sized objects before the ionization and electrostatic forces “destroy” it. These developments led to establishing new methodologies in structural biology, such as serial femtosecond crystallography (SFX) [1] and very rapid development of new sample delivery methods but also allow benefiting from coherent diffractive imaging techniques to investigate virtually any single nanosized object with extraordinary temporal resolution.

Figure 1: (A)The generation of ultrabright and ultrashort pulses of X-rays comes from the interaction of the high-energy

relativistic electrons that are directed through special arrangements of magnets (undulators). (B) Aerial view of the European XFEL campus with the city of Hamburg in the background. The lines superimposed on the photograph indicate the underground tunnels that start on the DESY campus in Hamburg and end in the experiment hall under the main building in Schenefeld. The red lines indicate the electron beamlines, the orange lines the X-ray beamlines.

The European X-Ray Free-Electron Laser (European XFEL) is currently operational since almost 2 years when the first lasing in the hard X-ray regime was achieved [2]. Shortly after the European XFEL facility was inaugurated in September 2017 and the Early Users Experiments (EUE) commenced in autumn 2017 exploiting first two scientific instruments, namely the FXE (Femtosecond X-ray Experiments) [3] and SPB/SFX (Single Particles, Clusters and Biomolecules & Serial Femtosecond Crystallography) [4] that were commissioned and brought into operation throughout the first half of 2017. In the meantime, installation and commissioning of further soft and hard X-ray instruments has been completed and the regular user program is being executed at all 6 Scientific Instruments.

In this talk I will present the current status of the facility including the X-ray laser accelerator, the X-ray beam transport and optics and the currently operational scientific instruments. Some early scientific results obtained during user experiments will be presented and discussed.

References 1 Chapman, H. N.; et al. Femtoseocnd X-ray Protein Nanocrystallography, Nature 2011, 470, 73-77 2 Tschentscher, T.; et al. Photon beam transport and Scientific Instruments at the European XFEL, Appl. Sci. 2017, 7, 592 3 Galler A.; Gawelda W.; et al. Scientific instrument Femtosecond X-ray Experiments (FXE): instrumentation and baseline

experimental capabilities, J. Synchrotron Rad. 2019, 26, 1432-1447 4 Mancuso, A.; et al. The Single Particles, Clusters and Biomolecules and Serial Femtoseocnd Crystallography Instrument of the

European XFEL: initial instalation, J. Synchrotron Rad. 2019, 26, 660-676

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INVITED Tracking the electronic and structural configurations of earth-

abundant photosensitizers and water splitting catalysts for artificial photosynthesis

Dooshaye Moonshiram Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain


Replacing fossil fuels with renewable energy sources is one of the most promising research fields that can provide a solution towards solving the global energy crisis. Although today’s state of the art technology has achieved progress in producing electricity using solar, wind, tidal, and hydroelectric power sources, these intermittent sources will find limited applications without proper energy storage and transport. One way of storing solar energy is to convert it into chemical energy through fuel forming reactions inspired by natural photosynthesis, such as the light induced water splitting into hydrogen and oxygen. The prospect of using molecular hydrogen as a carbon-free fuel has motivated the development of catalysts for photo-induced water oxidation, proton reduction, and their integration in catalyst-photosensitizer systems. However, although active synthetic efforts have been invested in developing efficient water splitting complexes, there is no clear understanding between their stability and performance to their structures and ligand geometries.

In this context, time-resolved X-ray absorption with X-ray emission spectroscopy are powerful tools for visualizing the “real-time” electronic and geometric changes involved in a photocatalytic system with picosecond-microsecond time resolution. This talk will demonstrate the reaction pathways of several cobalt, nickel and copper-based photosensitizer and hydrogen evolving complexes, examined in unprecedented detail with picosecond time resolution. The mechanistic pathways followed by these catalysts with spectroscopic and kinetic characterization of the different intermediates towards the hydrogen evolution pathway and H-H bond formation will be explained. Experimental results combined with theoretical simulations will reveal new aspects about the catalytic intermediates, and step by step time frames used for the hydrogen evolution reaction in purely aqueous conditions. Results shown will enable the rational design of molecular hydrogen-evolving photocatalysts that can perform beyond the current microsecond time scale, and suggest ways in which the ligand structures can be adjusted to facilitate protonation and catalytic efficiency.

FIGURE: Scheme for the ultrafast study of the different catalysts

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INVITED Tracking the electronic and structural configurations of earth-

abundant photosensitizers and water splitting catalysts for artificial photosynthesis

Dooshaye Moonshiram Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain


Replacing fossil fuels with renewable energy sources is one of the most promising research fields that can provide a solution towards solving the global energy crisis. Although today’s state of the art technology has achieved progress in producing electricity using solar, wind, tidal, and hydroelectric power sources, these intermittent sources will find limited applications without proper energy storage and transport. One way of storing solar energy is to convert it into chemical energy through fuel forming reactions inspired by natural photosynthesis, such as the light induced water splitting into hydrogen and oxygen. The prospect of using molecular hydrogen as a carbon-free fuel has motivated the development of catalysts for photo-induced water oxidation, proton reduction, and their integration in catalyst-photosensitizer systems. However, although active synthetic efforts have been invested in developing efficient water splitting complexes, there is no clear understanding between their stability and performance to their structures and ligand geometries.

In this context, time-resolved X-ray absorption with X-ray emission spectroscopy are powerful tools for visualizing the “real-time” electronic and geometric changes involved in a photocatalytic system with picosecond-microsecond time resolution. This talk will demonstrate the reaction pathways of several cobalt, nickel and copper-based photosensitizer and hydrogen evolving complexes, examined in unprecedented detail with picosecond time resolution. The mechanistic pathways followed by these catalysts with spectroscopic and kinetic characterization of the different intermediates towards the hydrogen evolution pathway and H-H bond formation will be explained. Experimental results combined with theoretical simulations will reveal new aspects about the catalytic intermediates, and step by step time frames used for the hydrogen evolution reaction in purely aqueous conditions. Results shown will enable the rational design of molecular hydrogen-evolving photocatalysts that can perform beyond the current microsecond time scale, and suggest ways in which the ligand structures can be adjusted to facilitate protonation and catalytic efficiency.

FIGURE: Scheme for the ultrafast study of the different catalysts

ORAL

Transitions in X-ray irradiated solid materials Beata Ziaja-Motyka,*a,b

aCFEL, DESY, Notkestrasse 85, 22607 Hamburg, Germany

bINP, PAS, Radzikowskiego 152, 31-342, Krakow, Poland. E-mail: [email protected]

The focus of this talk are diagnostics and modeling of X-ray induced structural transitions in solids. Two recent experiments are discussed in detail: (i) X-ray induced femtosecond graphitization of diamond [1], and (ii) amorphization of diamond by intense X-ray pulses [2,3]. Dedicated simulations reveal complex multistage evolution of these systems which diagnostics tools can confirm. Challenges remaining for accurate modeling of structural transition of solid materials and the quest for further improvements of the necessary diagnostics tools are explored.

FIGURE: Ultrafast graphitization of diamond triggered by soft X-ray pulse of 10 fs duration

References 1 F. Tavella et al., 'Soft x-ray induced femtosecond solid-to-solid phase transition', High Energy Density Physics 24, 2017, 22 2 I. Inoue et al., 'Observation of femtosecond X-ray interactions with matter using an X-ray - X-ray pump-probe scheme', PNAS 113, 2016,

1492–7 3 N. Medvedev, B. Ziaja, 'Multistep transition of diamond to warm dense matter state revealed by femtosecond X-ray diffraction', Scientific

Reports 8, 2018, 5284

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ORAL Ultrafast soft x-ray spectroscopy at the European XFEL

Daniel E. Rivas,* Thomas Baumann, Rebecca Boll, Alberto De Fanis, Jan Grünert , Patrik Grychtol, Markus Ilchen, Jia Liu, Tommaso Mazza, Jacobo Montaño, Valerija Music,

Yevheniy Ovcharenko, Nils Rennhack, Philipp Schmidt, Sergey Usenko, René Wagner, Pawel Ziokowski, Michael Meyer

aEuropean XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany; E-mail: [email protected]

The Small Quantum Systems (SQS) scientific instrument at the European XFEL is dedicated to the investigation of atoms, molecules, nanostructures and clusters with soft x-ray pulses. The SASE3 soft x-ray undulator supplies the instrument with femtosecond FEL pulses with photon energies between 260 eV and 3000 eV, with up to 2×1014 photons per pulse, at a repetition rate up to 27 kHz. By focusing with elliptical mirrors in Kirkpatrick-Baez configuration, a focal spot of approximately 1 µm in diameter is achieved, resulting in intensities beyond 1018 W/cm2. The combination of these parameters allows the investigation of multiphoton ionization processes in the natural time-scales of these atomic systems. The use of a synchronized optical laser additionally enables time-resolved measurements in a pump/probe configuration.

In this work we present the first results on time-resolved soft x-ray spectroscopy at the SQS instrument. The synchronized optical laser, centered at 1030 nm, provides pulses 1 mJ of energy and sub-40 fs duration. A fiber link in combination with an optical cross-correlator allows synchronizing the optical and x-ray pulses to few tens of femtoseconds. The timing jitter between them is measured on a single pulse basis behind the interaction region in a dedicated pulse-arrival monitor through spectral encoding in a few-micron thick Si3N4 sample1. This tool allows to improve the time resolution to below the jitter-level, by accounting for the measured time of arrival of each single-shot, opening the possibility to explore few-fs dynamics.

In a proof-of-principle experiment we characterize these capabilities by measuring the time-dependance of the sideband intensity in a laser-assisted Auger decay process. The chosen target is atomic neon, which provides a clear Auger electrons line (KLL) at 804.3 eV kinetic energy, which is detected by an electron time-of-flight spectrometer. Sidebands on the electron kinetic energy arise due to the dressing of the optical field at the moment of ionization, thus allowing to extract information on x-ray pulse duration and the timing between the two fields. Additional results will be discussed towards time-resolved dynamics involving shorter pulse durations and simple molecular systems. These results establish the optical/x-ray pump/probe capabilities at the SQS instrument and opens up the door for time-resolved soft x-ray spectroscopy on more complex targets.

Notes and References 1 Bionita, M. R. et al., Optics Express 2011, Vol. 19, 21855. 2 Meyer, M. et al., Physical Review Letters 2012, Vol. 108, 06007.

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ORAL Ultrafast soft x-ray spectroscopy at the European XFEL

Daniel E. Rivas,* Thomas Baumann, Rebecca Boll, Alberto De Fanis, Jan Grünert , Patrik Grychtol, Markus Ilchen, Jia Liu, Tommaso Mazza, Jacobo Montaño, Valerija Music,

Yevheniy Ovcharenko, Nils Rennhack, Philipp Schmidt, Sergey Usenko, René Wagner, Pawel Ziokowski, Michael Meyer

aEuropean XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany; E-mail: [email protected]

The Small Quantum Systems (SQS) scientific instrument at the European XFEL is dedicated to the investigation of atoms, molecules, nanostructures and clusters with soft x-ray pulses. The SASE3 soft x-ray undulator supplies the instrument with femtosecond FEL pulses with photon energies between 260 eV and 3000 eV, with up to 2×1014 photons per pulse, at a repetition rate up to 27 kHz. By focusing with elliptical mirrors in Kirkpatrick-Baez configuration, a focal spot of approximately 1 µm in diameter is achieved, resulting in intensities beyond 1018 W/cm2. The combination of these parameters allows the investigation of multiphoton ionization processes in the natural time-scales of these atomic systems. The use of a synchronized optical laser additionally enables time-resolved measurements in a pump/probe configuration.

In this work we present the first results on time-resolved soft x-ray spectroscopy at the SQS instrument. The synchronized optical laser, centered at 1030 nm, provides pulses 1 mJ of energy and sub-40 fs duration. A fiber link in combination with an optical cross-correlator allows synchronizing the optical and x-ray pulses to few tens of femtoseconds. The timing jitter between them is measured on a single pulse basis behind the interaction region in a dedicated pulse-arrival monitor through spectral encoding in a few-micron thick Si3N4 sample1. This tool allows to improve the time resolution to below the jitter-level, by accounting for the measured time of arrival of each single-shot, opening the possibility to explore few-fs dynamics.

In a proof-of-principle experiment we characterize these capabilities by measuring the time-dependance of the sideband intensity in a laser-assisted Auger decay process. The chosen target is atomic neon, which provides a clear Auger electrons line (KLL) at 804.3 eV kinetic energy, which is detected by an electron time-of-flight spectrometer. Sidebands on the electron kinetic energy arise due to the dressing of the optical field at the moment of ionization, thus allowing to extract information on x-ray pulse duration and the timing between the two fields. Additional results will be discussed towards time-resolved dynamics involving shorter pulse durations and simple molecular systems. These results establish the optical/x-ray pump/probe capabilities at the SQS instrument and opens up the door for time-resolved soft x-ray spectroscopy on more complex targets.

Notes and References 1 Bionita, M. R. et al., Optics Express 2011, Vol. 19, 21855. 2 Meyer, M. et al., Physical Review Letters 2012, Vol. 108, 06007.


Sponsored by:Promoted by:

Wednesday 6th11:00 Conference Opening

11:10 Ursula Keller (PCCP Lecture on Ultrafast Science and Technology)

11:55 Fernando Ardana-Lamas

12:25 Larry Lüer

12:55 Lunch

15:00 Jens Biegert

15:30 Cruz Méndez

16:00 Rebeca de Nalda

16:30 Coffe Break

17:00 Abderrazzak Douhal

17:20 Marta L. Murillo-Sánchez

17:40 Manuel Macías-Montero

18:00 Poster Session

Friday 8th9:00 Mauro Nisoli (PCCP Lecture

on Ultrafast Science and Technology)

9:45 María Teresa Flores

10:15 Elisabet Romero

10:45 Coffe Break

11:15 Wojciech Gawelda

11:45 Dooshaye Moonshiram

12:15 Beata Ziaja-Motyka

12:35 Daniel Rivas

12:55 Lunch

15:00 Farewell

Thursday 7th9:00 Franck Lépine (PCCP Lecture

on Ultrafast Science and Technology)

9:45 Rosario González-Férez

10:15 Klavs Hansen

10:45 Coffe Break

11:15 Carlos Hernández-García

11:45 Etienne Plésiat

12:15 Emilio Pisanty

12:35 Álvaro Jiménez-Galán

12:55 Lunch

15:00 Dolores Martín

15:30 Johannes Feist

16:00 Asier Longarte

16:30 Coffe Break

17:00 Christopher Arrell

17:20 Laura Cattaneo

17:40 Jose A. Pérez-Hernández

18:00 Poster Session

19:30 Social program: Tapas

Program at-glance

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