J. Fils for the PHELIX team
GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
Sept. 27 2010SpeyerEMMI Workshop
The PHELIX High Energy Laser Facility
Overview
Switch Yard
70 m
Double-pass 31.5 cm amplifier
Schematic view of the PHELIX facility
Injection box
Mai
n A
mp
lifi
erS
enso
r
Faraday
Isolator
fs Front End
Fiber ns Front End
Pre-amplifier2 x 19 mm heads1 x 45 mm head
X-ray Lab(low energy)
TW compressor
Target chamber
Z6 experimental
area
Heavy ions
Laser Bay
Compressor
Target Chamber se
nso
r
Areas recently improved
Performance of PHELIX in 2010
Long pulse Short pulse
Pulse duration 0.7 – 20 ns 0.5 – 20 ps
On-target energy 0.3 – 1 kJ 120 J
Maximum intensity 1016 Wcm-2 1020 Wcm-2
Repetition rate at Joule level
1 shot every 3 min
Repetition rate at maximum power
1 shot every 1h*
Temporal contrast 50 dB60 to 80 dB depending on
settings
* with use of the adaptive optics
A selection of representative experimental results
• Progress in ion stopping (Courtesy of A. Frank)
– PHELIX together with nhelix yields significant improvement in quality of experimental data.
• Progress in particle acceleration (Courtesy of K. Harres)
– Up to 14 MeV protons were collimated using a coil
• Progress in X-ray laser development (Courtesy of D. Zimmer)
– The DGRIP scheme achieves lasing at 7.26 nm with as little as 30 J of pump laser energy.
reference 6. 8 MeV 9.0 MeV
Converging proton beams
Stack located 405 mm from the target
Status &Recent Improvements
of the Facility
Adjustable pulse length and improved intensity contrast
1050 1055 10600
0.5
1Shot 525
Wavelength (nm)
Inte
nsi
ty (
no
rmal
ized
)
5.9 nm
• Modified pulse stretcher for adjustable pulse duration control
• A series of 4 Pockels cells distributed in the font end avoids pre-pulses
-5 -4 -3 -2 -1 0 110-10
10-8
10-6
10-4
10-2
100
inte
nsi
ty (
no
rmal
ized
)
ASE level
Time (ns)
• Spectral width enhanced by use of a birefringent filter
Main amplifier with energies in the kilojoule range
With a gain of up to 100 (17.5 kV), the main amplifier works as expected, only limited by the damage threshold of the Faraday rotator
0
100
200
300
400
500
600
700
800
900
1000
5 6 7 8 9 10 11
17.5 kV
Ou
tpu
t en
erg
y (J
)
Pre/amplifier energy (J)
17 kV
16 kV
16.5 kV
Direct on-shot measurement of the pulse duration
• A single-shot autocorrelator is used for alignment and on-shot measurements
-2000 0 20000
0.2
0.4
0.6
0.8
1
time delay (fs)
Fourier transform limit
measurement
Together with a twofold increase in energy, we plan to upgrade the peak power to more than 750 TW in 2010
Shot 1071
Active wavefront correction
Incoming pulse(distorted wavefront)
DeformablemirrorWavefront
sensor
Outgoing pulse(corrected wavefront)
Active wavefront correction
• Three types of aberrations are being found in a complex laser system
Active wavefront correction
• On-shot aberrations at pre-amplifier level reduced by 60%
• Waiting time between pre-amplifier shots reduced from 10 down to 3 minutes
• Increase of main-amplifier repetition rate to 1 shot/hour.
without correction with correction
We plan to improve the contrast by use of an ultrafast OPA
2 nJ2 nJ
1 ps1 ps
MiraMiraFreq.Freq.shiftershifter
Stretch.Stretch.Ampli.Ampli.Yb:KYWYb:KYW
Comp.Comp.
Stretch.Stretch.× 10× 10
1054 nm1054 nm
100 fs100 fs
OPAOPA
1040 nm, 100 ps1040 nm, 100 psSignalSignal
300 µJ300 µJ
• ASE is mostly created in the front-end because of low power available from the oscillator
• Boost this power using an ultrafast optical parametric amplifier
– A gain in contrast of 105 expected
– Low pre-pulse level
– Higher energy stability because of diode-pumped amplifier
This development is done within the frame of the Helmholtz Institut Jena (HIJ)
SHGSHG
Extension of the experimental capabilities at Z6
Ion beam
2ω beam line
(in preparation)
10° beam line
(in operation)
100 TW beam line
(in preparation)
target
chamber
PHELIX
beam
PHELIX celebrates 2 years of operation
• PHELIX delivered more than 100 shifts in 2009, in line with the prediction
– The facility delivered its 2000th documented shot.
– An internal beamtime allowed to test the amplifier up to 920 J.
• PHELIX has a strong impact on the scientific program of GSI.
– Significant results were obtained in ion stopping experiments, manipulation of laser-accelerated particles and coherent X-ray generation
• We operate a recent facility which is being constantly improved
– PHELIX operates in the ns to sub-ps regime at three different experimental places
– Innovative solutions in many locations implemented
– Future upgrades are being actively pursued in
• contrast improvement (uOPA project)
• frequency conversion (2 project)
• experimental capability (100 TW project)
Summary
Thank you for your attention
Picture: G. Otto, GSI