K. Z. Hatsagortsyan, G. Yu. Kryuchkyan*, A. Ipp, J. Evers and C. H. Keitel
Max-Planck-Institut für Kernphysik, Heidelberg, Germany*Yerevan State University, Yerevan , Armenia
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Employment of Bragg scattering for enhancement of vacuum polarization effects
and of pair production for an ultra-short gamma-ray characterization
1
Outline
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Photon-photon scattering in a periodically modulated vacuum: Bragg scattering
Characterization of ultra-short pulses of γ-rays of GeV energies. Streaking method based on the strong field pair production:
from femtosecond time-scale up to zeptoseconds.
[SHEEP - streaking at high energies with electrons and positrons]
FROG…..RABBITT…..SPIDER
2
B
Vacuum polarization/photon-photon scattering
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Vacuum birefringence
photon-photon scattering
ConstF
Second harmonic generation with Kaplan, Ding, PRA 2000 Di Piazza, KZH, Keitel, PRL 2005
0F
crEE
fi kk
Moulin et al. ZPC 1996Bernard et al. EPJD 2000Lundström et al. PRL 2006
M=0 in B=const
Diffraction
Uniform medium
Nonuniform medium
ik fk
3
Modulated vacuum: Bragg scattering
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Bragg-scattering condition: nSind 2q
4
B012 qnkk
Bragg scattering vs.Photon-photon scattering
26
4~ Cm
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
V
mEEmNjWcr
sp
6442
12 ~~
88
22 VENEj
V
kEEmWWcr
spstim 3
364
3 ~~ 0
1~w
k
320
32
30 ~~ 12 VRrdeRW qkki
Bragg
z
stim
Bragg LWW ~
Lundström et al. PRL 2006
phase-matching factor
Bragg-scattering condition:
kE
k 3
2
8
5
yxLLk 2/1~
Bragg scattering of light in vacuum with multiple laser beams
Kryuchkyan, KZH, PRL 107, 053604 (2011)
enhancement factor with respect to photon-photon scattering
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
102
13;
13 3
23
N
NN
NIIII
stim
BraggtotBragg
totstim
shotNfscmW ph /5100/103 222
6
z
y
Outline
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Photon-photon scattering in a periodically modulated vacuum: Bragg scattering
Characterization of ultra-short pulses of γ-rays of GeV energies. Streaking method based on the strong field pair production:
from femtosecond time-scale up to zeptoseconds.
[SHEEP - streaking at high energies with electrons and positrons]
7
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Time-resolved intra-nuclear dynamics
MeV-GeV excitation energyZeptosecond time-scale
Pump
Probe
PumpProbeQuark system
Why ultra-short pulses of GeV γ-rays are important?
8
Yoctosecond double pulses of γ-rays
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
A. Ipp, C. H. Keitel, J. Evers, PRL103, 152301 (2009)
heavy-ion collisions
9
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Characterization of ultra-short pulsesStreak-camera
10
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Streaking mechanismConversion photons to electrons
For hard x-rays 10 KeV - 1MeV:Compton ionization
For XUV 100 eV - 1 KeV:Photoionization
For γ-rays >MeV:e+e- pair production
11
Streak-camera for γ-rays via strong field e+e- pair production
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Ipp, Evers, Keitel, KZH, PLB 702, 383 (2011)
SLAC experiment D. Burke et al., PRL 79, 1626 (1997)
12
Streak-camera for γ-rays via strong field e+e- pair production
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
mceE
m
NmN
NemN
iti
itt
ee
itt
ee
382
1,
1,
2
3/22
3/82/32
tt ,/1
tsSN /
crsi EEE ,
si
1ii
IP+SP should not create e+e-
Fast oscillations due to IP
Photoemission is negligible
13
Streak-camera for γ-rays: Parameters
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
303,1011 iiii Photoemission is negligible:
titi
m
382
2
stsSN /
t 1.0~// ttists
14
Streak-camera for γ-rays: 0.3-30 GeVfrom fs up to zs resolution
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011 15
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011
Conlcusion
• Bragg scattering can enhance photon-photon scattering
• A detection scheme has been proposed for the characterization of short γ-ray pulses in the GeV energy range based on pair creation. Sub-attosecond time resolution could be achieved with high-order harmonic generation in the upcoming ELI facility.
16
Thank you for your attention!
"PW Lasers at Hard X-ray Sources" Dresden-Rossendorf, 7 Sep 2011 17
