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