Laser Output Performance and Temporal Quality Enhancement at the J-KAREN-P Petawatt Laser Facility

Abstract

We described the output performance and temporal quality enhancement of the J-KAREN-P petawatt laser facility. After wavefront correction using a deformable mirror, focusing with an f/1.3 off-axis parabolic mirror delivered a peak intensity of 1022 W/cm2 at 0.3 PW power levels. Technologies to improve the temporal contrast were investigated and tested. The origins of pre-pulses generated by post-pulses were identified and the elimination of most pre-pulses by removal of the post-pulses with wedged optics was achieved. A cascaded femtosecond optical parametric amplifier based on the utilization of the idler pulse rather than the signal pulse was developed for the complete elimination of the remaining pre-pulses. The orders of magnitude enhancement of the pedestal before the main pulse were obtained by using a higher surface quality of the convex mirror in the Öffner stretcher. A single plasma mirror was installed in the J-KAREN-P laser beam line for further contrast improvement of three orders of magnitude. The above developments indicate, although it has not been directly measured, the contrast can be as high as approximately 1015 up to 40 ps before the main pulse. We also showed an overview of the digital transformation (DX) of the system, enabling remote and automated operation of the J-KAREN-P laser facility.

The Role of Collision Ionization of K-Shell Ions in Nonequilibrium Plasmas Produced by the Action of Super Strong, Ultrashort PW-Class Laser Pulses on Micron-Scale Argon Clusters with Intensity up to 5 × 1021 W/cm2

“…Experiments were performed on the irradiation of argon clusters with laser pulses of ultrarelativistic intensity generated by J-KAREN-P laser system at QST-KPSI [15,16]. The clusters were formed in a gas cooled down to cryogenic temperatures and injected (injection system is described in [17]) into vacuum through a conical nozzle with an opening angle of 40 degrees.…”

High-energy laser facility PHELIX at GSI: latest advances and extended capabilities

“…However, because of the combined increase in focused intensities and requirements from users, the temporal contrast of the laser pulses has become an increasingly crucial feature. Considerable effort has been invested in this topic worldwide [23][24][25] and also at PHELIX, in order to improve the leading edge of the pulse with an emphasis on the reduction of the amplified spontaneous emission (ASE) plateau and elimination of unwanted prepulses.…”

A Promising Route to Compact and Economic Sub-15 fs, PW-Level Ti:Sapphire Lasers

“…On the one hand, CPA is more mature and more robust in the aspects of pump-to-seed conversion and spatiotemporal synchronization, which ensures high conversion efficiency and good energy stability, and loosens the requirements for pumping systems [5][6][7]. Nowadays, PW-and 10 PW-level femtosecond lasers based on the Ti:sa CPA technique have been built and operated worldwide, and the corresponding focused peak intensities have reached 10 22 and even 10 23 W/cm 2 [8][9][10][11][12][13][14][15]. Such superintense lasers can create extreme conditions and provide unprecedented means for high-field sciences [16][17][18][19][20][21].…”