s. karsch-the petawatt field synthesizer – current status and recent progress

The

Petawatt Field Synthesizer

Current status and recent progress

Laboratory for Attosecond and High-Field PhysicsMax-Planck-Institut für Quantenoptik

Garching, Germany&

Ludwig-Maximilians-Universität München, Garching

ELI-BEAMLINES SCIENTIFIC CHALLENGES WORKSHOP, PragueApril 26-27, 2010

Stefan Karsch

Dienstag, 27. April 2010

Coworkers

current:

I. Ahmad, S. Klingebiel, M. Siebold, C. Wandt, Zs. Major, S. Trushin, Ch. Skrobol, M. Mero, A. Popp, J. Irlinger, F. Krausz

former: M. Siebold, J. Hein, J. Osterhoff, J. Fülöp, S. Kruber


ELI Beamlines - PFS


!"#$%%&'()"*+*,-.*/)0&1/"*

2*345*

!""#$%&'()*'+',-.*'0#67(%(89*:,..;*/<1/*

!""#$%&'()*',',-.*'0#67(%(89*:,..;*/<1/*

!""#$%&'()*'-',-.*'0#67(%(89*:,..;*/<1/*

."/%&'()*''0,12'!,=,>*2?@*A0&1%$70*

:,..;*/<1/*

+3'.4'56"78'0,12'!,=,>*()*B$C.&//6*-%&"6%&1/*/<1/*

."/%&'()*''0,12'!,=,>*D?@*A0&1%$70*

:,..;*/<1/*

!9:;<.'."/%&'()*#'B$C.&//6*ED?@*A0&1%$70*

-%&"6%&1/*/<1/*

+3')=>'+8?@>'A'BC#'

+D,='>'+33'?@'>'+E'C#'

+D,='>'+33'?@>'+E'C#'

?FGHDFI$%I#F$J'$%#$'K'L#%&'C(7F6F$J'M1"N7'*HJ#F7#'

%D'(IO'*P'(77%6%&(N"I'

Q<R'>'QD&(J'G%I%&(N"I'

.6(#)('*HJ#F7#'4ST'

+3'='>'+3?@'

E3'='>'+3?@'

-33'='>'3U+?@'

,1',33')='>+'8?@>+3C#' ''9**6F7(N"I#'F1(%0#<%&)G*A$(10H$#&%*I*1&'0)$&%*"#$07#0"J*

!%()

>*L6#%'#/F$7HJ(&O*

E3'='>'3U+?@'

VHFI'OF#8'*

L)*''

''''''''$%7H

I"6"G

J''

TL6N#6(5

'*L)*

'

''''''''$%7H

I"6"G

J'

.L)*

W''X6(#H6(

)*'

''''''''''$%7

HI"6"

GJ'

ELI beamlines facility


ELI Beamlines Laser

Peak intensity: 1023 W/cm2

Plasma formation threshold: 1010 W/cm2

⇒ Temporal contrast: ≈ 1013 W/cm2

Pulse shaping capabilities directly benefit from spectral bandwidth ⇒ High energy, broadband seed for power amplifiers is desirable

log(I)

time

plasma formation threshold

0

-10

-15

-5

!"#$%%&'()"*+*,-.*/)0&1/"*

2*345*

!""#$%&'()*'+',-.*'0#67(%(89*:,..;*/<1/*

!""#$%&'()*',',-.*'0#67(%(89*:,..;*/<1/*

!""#$%&'()*'-',-.*'0#67(%(89*:,..;*/<1/*

."/%&'()*''0,12'!,=,>*2?@*A0&1%$70*

:,..;*/<1/*

+3'.4'56"78'0,12'!,=,>*()*B$C.&//6*-%&"6%&1/*/<1/*

."/%&'()*''0,12'!,=,>*D?@*A0&1%$70*

:,..;*/<1/*

!9:;<.'."/%&'()*#'B$C.&//6*ED?@*A0&1%$70*

-%&"6%&1/*/<1/*

+3')=>'+8?@>'A'BC#'

+D,='>'+33'?@'>'+E'C#'

+D,='>'+33'?@>'+E'C#'

?FGHDFI$%I#F$J'$%#$'K'L#%&'C(7F6F$J'M1"N7'*HJ#F7#'

%D'(IO'*P'(77%6%&(N"I'

Q<R'>'QD&(J'G%I%&(N"I'

.6(#)('*HJ#F7#'4ST'

+3'='>'+3?@'

E3'='>'+3?@'

-33'='>'3U+?@'

,1',33')='>+'8?@>+3C#' ''9**6F7(N"I#'F1(%0#<%&)G*A$(10H$#&%*I*1&'0)$&%*"#$07#0"J*

!%()

>*L6#%'#/F$7HJ(&O*

E3'='>'3U+?@'

VHFI'OF#8'*

L)*''

''''''''$%7H

I"6"G

J''

TL6N#6(5

'*L)*

'

''''''''$%7H

I"6"G

J'

.L)*

W''X6(#H6(

)*'

''''''''''$%7

HI"6"

GJ'


Max-Planck-Institutfür Quantenoptik

Ludwig-MaximiliansUniversität München

5 fs 3 J 10 Hz

High bandwidth(OPCPA) Large crystals High – rep.

pump

Yb:YAG CPA pump laserLarge aperture DKDP OPCPAbulk/chirped mirror compression

Diode pumpingThin KDP or DKDP

CPAHigh pump intensityps pulse duration

MPQ project PFS: Strategy


Basic concept and layout


OPCPA design

~20 J, 1-2 ps @ 515 nmfrom pumplaser

in several beams

ultrabroadband seedfrom frontend

700 nm – 1400 nm


Zs. Major et al., Review of Laser Engineering, 37, 431 (2009)

OPCPA design

• Large aperture DKDP crystals Lozhkarev et al. Laser Phys. Lett. 4, 421 (2007)

• Total pump energy: 20 J @ 515 nm• 1D modelling with saturation (pump depletion)• no dispersion included

stage pump energy

ampl. signal energy

crystal length

1 2.5 mJ 500 µJ 3.8 mm

2 20 mJ 3.5 mJ 3.8 mm

3 200 mJ 40 mJ 3.5 mm

4 1 J 169 mJ 3.0 mm

5 3 J 722 mJ 2.8 mm

6 5 J 1.7 J 2.4 mm

7 5 J 2.8 J 1.7 mm

8 5 J 3.8 J 1.5 mm


frontend

1. CPA pump laser seed: - 30 % of oscillator output- soliton self-frequency shift in a photonic crystal fiber to 1030 nm C.Y. Teisset et al., Opt. Exp. 13, 6550 (2005)- Yb:Glass fiber amplifier: 1W at 70 MHz (14 nJ)

21

2. OPA chain seed: - 70 % of oscillator output – stretched – amplified- compressed- cascaded hollow-core fiber (HCF) scheme for spectral broadeningAhmad et al., Appl. Phys. B, in press (2009)


frontend• Ti:Sa oscillator • Ti:Sa 10-pass (modified Femtopower CompactPro): up to 2 mJ, 60 nm, 1 kHz• prism compressor: ~23 fs

spectral shifting for pumplaser seed

broadband seed generation


frontend

2

1

50 µJ in the range of 700 – 1400 nm


26 HD mirrors (1” dia.) , 2-pass configuration (52 reflections), ~ -500 fs2/reflection, angle of incidence: 10°, separation: 96 mm

- stretched pulse duration: 4.8 ps (FWHM)- throughput ~ 90 %- output energy 1.2 mJ- pulse duration after compressor: 19.1 fs

frontend

High-dispersive mirrors instead of prism compressor in CPA systemPervak et al., Opt. Exp. 16, 10220 (2008) Pervak et al., Opt. Exp. 17, 19204 (2009)


frontend


FROG-trace

hybrid compressor all-dispersive mirror compressor


frontend


excellent beam quality

far field near field


pump laser


pump laser

6.5 m grating separation

300 mJ, 3.5 nm, 10 Hz


pump laser

300 mJ, 3.5 nm, 10 Hz


Pumplaser

Pulse compression:

• 1.4 ± 0.3 ps• remaining higher orders resulting

in temporal wings• spectrum of ~ 3.5 nm could

support ~ 800 fs TL pulses

→ more careful alignment for cleaner compressed pulse

→ received Dazzler for fine tuning

Single-shot FROG


Next steps: pump laser design

New simulations of amplification in diode-pumped Yb:YAG amplifiers:• include multipass pumping scheme• wavelength dependence of pump


Next steps: pump laser design

2 × 240 mJ 4 × 1 J 4 × 12 J

• Yb:YAG crystals in stock• setup is under way


Timing jitter between pump and seed


- total path difference ~ 400 m- max. jitter: ~ 100 fs = 30mm- stabilization to 10-7 needed




Sum frequency generation in 120 µm BBO

spectrometer

I

l

spectral gating techniqueT. Miura et al. Opt. Lett. 25, 1795-1797 (2000)



Sum frequency generation in 120 µm BBO

spectrometer

I

l

- resolution depends on pulse chirp and spectral resolution of spectrometer

spectral gating techniqueT. Miura et al. Opt. Lett. 25, 1795-1797 (2000)


20

jitter problems I

(shot-to-shot)


21

how to produce annoying jitter issues® Take a vacuum pump® Connect it to an unused part of the optical table ® Hide it behind a laser protection wall® Switch it on and off from time to time...


jitter problems II

(shot-to-shot)


23

active stabilization

® significantly reduced point-to-point jitter® large, but slow drift still present can be

compensated at 10 Hz

spectral acquisition = jitter

average

difference > limit?

reference shot 2 shot 3 shot 4

move delay stage by difference

Sum frequency fluctuations - inacceptable before stabilization

- now 10% fluctuation- start OPA experiments


24

active stabilization

stabilized

stabilized not stabilized

-stabilized with av 2, limit 100 fs - std =105 fs


finally: first broadband OPCPA gain

25

shot-to-shot-amplification stability 11% RMS

Gain from 750 to almost 1400 nm:However, strong modulations

due to large spectral intensity variations and over-saturation in too thick crystal.

Next experiments will use 3 mm crystal


26

Comparison with simulations

We seem to understand what is happening...Dienstag, 27. April 2010

Summary and next steps

• Frontend to produce optically synchronized seed pulses is complete.

• Pump laser chain: - ~100 mJ compressed to ~1.4 ps - large timing jitter from air fluctuations and mechanical instabilities can be reduced to below ~100 fs by → permanent beam tubes → automated slow drift correction - feasible design for next amplification stages to reach ~50 J

→ First OPCPA experiments show bandwidth for efficient short pulse generation


5 fs 1 J 1 kHz

ELI strategy

High bandwidth(OPCPA) Large crystals High – rep.

pump

Yb:YAG CPA pump laserLarge aperture KDP OPCPAbulk/chirped mirror compression

Diode pumpingThin KDP or DKDP

CPAHigh pump intensity


Towards ELI frontend

Schemes for upscaling the pumplaser repetition rate

• thin-disk approach: Max-Born-Institut, Berlin 100 Hz, ~300 mJ, 1.5 ps (@ several tens of mJ)

Max-Planck-Institut für Quantenoptik, Garching 3 kHz, ~30 mJ, 1.6 ps

→ limited total energy that can be extracted due to transverse lasing if disk size is too large→ CW pumping technology is expensive

• gas-cooled slab approach: e.g. Mercury project

→ higher demands on pump-beam quality for efficient pumpingDienstag, 27. April 2010

MPQ - Current System (T. Metzger)

• regenerative amplifier (CPA)• Ti:sa osc, fiber preamp. @1030nm • 25 mJ @ 3 kHz (32 mJ before comp.)• 1.6 ps pulse duration • total gain of 3 x 1010 (inc. fiber amp)• 1 nm bandwidth• 280 W Pump power (5.2 kW/cm²)• pump spot Ø 2,6 mm• round trip gain 1.2 (inc. losses)• round trip losses 6%• disk gain in V-pass 1.13• disk thickness 1/10 mm• < 0.7 % pulse-to-pulse stability (RMS)


Multipass in Constructionmirror holder 4-f imaging

vacuum chamber

Yb:YAG disk amplifier head

2 x 10 V-passes via the disk


s. karsch-the petawatt field synthesizer – current status and recent progress

Documents