Quantum Optics @ OWL. D. Dravins 1, C. Barbieri 2 V. Da Deppo 3, D. Faria 1, S. Fornasier 2 R. A. E....

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Quantum Optics @ OWLQuantum Optics @ OWL

D. Dravins 1, C. Barbieri

V. Da Deppo 3, D. Faria

Fornasier 2

R. A. E. Fosbury 4, L. Lindegren

G. Naletto 3, R. Nilsson

Occhipinti 3

F. Tamburini 2, H. Uthas

Zampieri 5

(1) Lund Observatory(2) Dept. of Astronomy, University of Padova

(3) Dept. of Information Engineering, Univ. of Padova(4) ST-ECF, ESO Garching

(5) Astronomical Observatory of Padova

• Explore parameter domains beyond those of today’s astronomy

• Observe what cannot be seen by imaging, photometry, spectroscopy, polarimetry, nor interferometry

• Open up quantum optics as another information channel from the Universe!

BLACKBODY ---

SCATTERED ---

SYNCHROTRON ---

LASER ---

CERENKOV ---

COHERENT ---

WAVELE

ILTERS

OBSERVER

Information content of light. IInformation content of light. I

D.Dravins, ESO Messenger 78, 9 (1994)

Intensity interferometryIntensity interferometry

Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)

• PHOTONS ARE COMPLEX ! !

• Photon streams carry information in the temporal ordering of photon arrival times

• Individual photons carryorbital angular momentum, can have hundreds of states

Quantum effects in cosmic light

Examples ofastrophysical

lasers

J. TalbotLaser Action in Recombining PlasmasM.Sc. thesis, University of Ottawa (1995)

Hydrogen recombinationlasers & masersin MWC 349 A

Circumstellar disk surrounding the hot star MWC 349. Maser emissions are thought to occur in outer regions while lasers are operating nearer to the central star.

V. Strelnitski; M.R. Haas; H.A. Smith; E.F. Erickson; S.W. Colgan; D.J. HollenbachFar-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A Science 272, 1459 (1996)

Quantum Optics & CosmologyQuantum Optics & Cosmology

The First Masersin the Universe…

M. Spaans & C.A. NormanHydrogen Recombination Line Masers at the Epochs of Recombination and ReionizationApJ 488, 27 (1997)

The black inner regiondenotes the evolutionof the universe beforedecoupling.

Arrows indicate maseremission from the epochof recombination andreionization.

Synergy OWL ― SKASynergy OWL ― SKA

SKA: Hydrogen recombination

lasers in the very early Universe

OWL: Hydrogen recombination lasers in

the nearby Universe

Emission-line lasersin Eta Carinae

Eta Carinae

Mid-IR (18 μm) images from 4-m Blanco telescope at Cerro Tololo.

Field 25 arcsec

S. Johansson & V. S. LetokhovLaser Action in a Gas Condensation in the Vicinity of a Hot StarJETP Lett. 75, 495 (2002) = Pis’ma Zh.Eksp.Teor.Fiz. 75, 591 (2002)

Model of a compact gas condensation near η Car with its Strömgren boundarybetween photoionized (H II) and neutral (H I) regions

S. Johansson & V.S. LetokhovAstrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta CarinaeA&A 428, 497 (2004)

Emission fromneutron stars,

pulsars & magnetars

T.H. Hankins, J.S. Kern, J.C. Weatherall, J.A. EilekNanosecond radio bursts from strong plasma turbulence in the Crab pulsar Nature 422, 141 (2003)

V.A. Soglasnov et al.Giant Pulses from PSR B1937+21 with Widths ≤ 15 Nanoseconds and Tb ≥ 5×1039 K, the Highest Brightness Temperature Observed in the Universe, ApJ 616, 439 (2004)

Longitudes of giantpulses comparedto the average

profile.Main pulse (top);

Interpulse (bottom)

Coherent emission from magnetars

o Pulsar magnetospheres emit in radio;higher plasma density shifts magnetar emission to visual & IR (= optical emission in anomalous X-ray pulsars?).

o Photon arrival statistics (high brightness temperature bursts; episodic sparking events?). Timescales down to nanoseconds suggested (Eichler et al. 2002).

Quantum Optics @ OWLQuantum Optics @ OWL

Detectinglaser effects in

astronomical radiation

Information content of light. IIInformation content of light. II

Photon correlation spectroscopyPhoton correlation spectroscopy

o To resolve narrow optical laser emission (Δν 10 MHz) requires spectral resolution λ/Δλ 100,000,000

o Achievable by photon-correlation (“self-beating”) spectroscopy ! Resolved at delay time Δt 100 ns

o Method assumes Gaussian (thermal) photon statistics

E.R.Pike, in R.A.Smith, ed. Very High Resolution Spectroscopy, p.51 (1976)

LENGTH,TIME &FREQUENCYFORTWO-MODESPECTRUM

E.R.Pike, in R.A.Smith, ed. Very High Resolution Spectroscopy, p.51 (1976)

LENGTH & TIME FOR SPECTROMETERS OF DIFFERENT RESOLVING POWER

o Analogous to spatial informationfrom intensity interferometry,photon correlation spectroscopydoes not reconstruct the shape of

the source spectrum, but “only” gives linewidth information

R. Loudon The

Quantum Theory of

Light (2000)

QUANTUM OPTICS

Information content of light. IIIInformation content of light. III

OWL Instrument Concept Study

The Road to Quantum Optics

High-Time Resolution Astrophysics

HIGHEST TIME RESOLUTION, REACHING QUANTUM OPTICS

• Other instruments cover seconds and milliseconds

• QUANTEYE will cover milli-, micro-, and nanoseconds, down to the quantum limit !

MILLI-, MICRO- & NANOSECONDS

• Millisecond pulsars ?• Variability near black holes ?• Surface convection on white dwarfs ?• Non-radial oscillations in neutron stars ?• Surface structures on neutron-stars ?• Photon bubbles in accretion flows ?• Free-electron lasers around magnetars ? • Astrophysical laser-line emission ?• Spectral resolutions reaching R = 100

million ?• Quantum statistics of photon arrival

times ?

p-mode oscillating neutron starp-mode oscillating neutron star

Non-radial oscillations in neutron starsMcDermott, Van Horn & Hansen, ApJ 325, 725 (1988)

MAIN PREVIOUS LIMITATIONS

• CCD-like detectors: Fastest practical frame rates: 1 - 10 ms

• Photon-counting detectors: Limited photon-count rates: ≳ 100 kHz

5 x 5 array of 20 μm diameter APD detectors (SensL, Cork)

32x32 Single Photon Silicon Avalanche Diode Array Quantum Architecture Group, L'Ecole Polytechnique Fédérale de Lausanne

PRELIMINARY OPTICAL DESIGNG.Naletto, F.Cucciarrè, V.Da Deppo

Dept. of Information Engineering, Univ. of Padova

ISSUES

* How to photon-count @ 1 GHz?* Large OWL images & Small APD detectors

CHOSEN CONSTRAINT

* Design within existing detector technologies

PRELIMINARY OPTICAL DESIGN

FEASIBILITY OF CONCEPT

* Slice OWL pupil into 100 segments

* Focus light from each pupil segment by one in an array of 100 lenses

* Detect with an array of 100 APD’s

The collimator

The collimator-lens system magnifies 1/60 times

(collimator focal length = 600 mm, lens focal length = 10 mm),

giving a nominal spot size of 50 m (1 arcsec source).

Light collection with a lens array

Each lens has a square aperture, 10 mm side

The beam section is an annulus, with 100 mm external diameter

Array lens mounting concept

TDC-25

Control logic(FPGA)

Creates the START signal for the time to

digital converters from the reference clock

E/O converterPLL

GPSreceiver

H-MASER E/O Converter20Mhz fiber

24 MHz27bitBUS Storage 1

Reference Clock

DESIGN CHALLENGES

* Imaging with GHz photon-count rates ?

* Spectroscopic imaging ?

* Megapixel detector arrays ?

“ULTIMATE” DATA RATES

* 1024 x 1024 imaging elements @ 100 spectral & polarization channels

* Each channel photon-counting @ 10 MHz, 1 ns time resolution

* Data @ 1015 photon time-tags per second = 1 PB/s (Petabyte, 1015 B) = some EB/h (Exabyte = 1018 B)

INSTRUMENT DESIGN ISSUES

• Telescope mechanical stability ? (small and well-defined vibrations, etc.)

• Temporal structure of stray light ? (scattered light may arrive with systematic

timelags)

• Atmospheric intensity scintillation ?

(ELT entrance pupils are complex)

INSTRUMENTATION PHYSICS

• Physics of photon detection ?(photons are never studied – one studies only photoelectrons which obey other quantum statistics)

• Physics of photon manipulation ? (does adaptive optics affect photon statistics?)

• Physics of photon propagation ? (statistics change upon passing a beamsplitter)

Advantages of very large telescopesAdvantages of very large telescopes

D.Dravins, L.Lindegren, E.Mezey, A.T.Young, PASP 109, 610 (1998)

Atmospheric

intensity scintillatio

Advantages of very large telescopes

Telescope diameter

Intensity <I> Second-order correlation <I2>

Fourth-order photon statistics <I4>

3.6 m 1 1 1

8.2 m 5 27 720

4 x 8.2 m 21 430 185,000

50 m 193 37,000 1,385,000,000

100 m 770 595,000 355,000,000,000

Precursors to ELT’s?Precursors to ELT’s?

MAGIC17 m diameter

La Palma

Studying rapid variabilityStudying rapid variability

Skinakas Observatory 1.3 m telescope, Oct.2004; OPTIMA (MPE) + QVANTOS Mark II (Lund)

Photons have many properties…

ORBITAL ANGULAR MOMENTUM !

Photon Orbital Angular Momentum

M.Padgett, J.Courtial, L.Allen, Phys.Today May 2004, p.25

For any given l, the beam has l intertwined helical phase fronts.

For helically phased beams, thephase singularity on the axisdictates zero intensity there.

The cross−sectional intensity pattern of all such beams hasan annular character that persistsno matter how tightly the beamis focused.

Martin Harwit(e.g., ApJ 597, 1266 (2003)

Orbital angular momentumAlthough polarization enables only two photon spin states, photons can exhibit multiple orbital-angular-momentum eigenstates, allowing single photons to encode much more information

At microscopic level, interactions have been observedwith helical beams acting as optical tweezers.

A small transparent particle was confined away fromthe axis in the beam's annular ring of light.

The particle's tangential recoil due to the helical phasefronts caused it to orbit around the beam axis.

At the same time, the beam's spin angular momentumcaused the particle to rotate on its own axis.

M.Padgett, J.Courtial, L.Allen, Phys.Today May 2004, p.25

PrototypePOAMinstrument

F. Tamburini, G. Umbriaco, G. Anzolin

Univ. of Padova

The Fork HologramThanks to: Anton Zeilinger groupInstitute of Experimental PhysicsUniversity of Vienna

The first three orders: l=0,1,2

The End

Quantum Optics @ OWL. D. Dravins 1, C. Barbieri 2 V. Da Deppo 3, D. Faria 1, S. Fornasier 2 R. A. E....

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