In this paper we discuss laser wake field acceleration experiments made at the PEtawatt pARametric Laser (PEARL).
Using free 2mm and 5 mm gas jet without preplasma we generated electron beam with energy up to 260 MeV. The
charge of quasimonoenergetic beams achieved 300 pC, angular divergence 0.2 degree. The special attention is paid for
diagnostics which is adapted for low repetition rate systems with low output parameters stability.
A prism/grating aberration-free stretcher for OPCPA system with chirp reversal is presented. A designed stretcher with a
conventional grating compressor allows to accurately compensate the residual dispersion of the system up to the 4-th
order inclusive. The peak power of 200 TW in the 45-fs pulse at the output of the OPCPA laser was achieved.
Output pulse energy of 300 J for a pulse duration of i-I .5 ns has been achieved in a six-stage neodymium phosphate
glass amplifier. A multistage spatial filter based on an pin hole line provides an aperture filling factor of 0.8 at the laser
output. As a result, stored energy has efficiently been extracted, and power elements of the system have been accommodated
on a single optical table. The energy efficiency of radiation conversion to the second harmonic is 55%. The laser is
synchronized with a cw femtosecond laser with accuracy 50 ns and is intended for pumping of a chirped-pulse optical
We describe spatial filters used in an Nd:glass laser with an output pulse energy up to 300 J and a pulse duration of 1 ns.
This laser is designed for pumping of a chirped pulse parametric amplifier. We present data required to choose a shape
and diameter of spatial filter lens, taking into account aberrations caused by spherical surfaces. Design features of spatial
filters and the procedure of them adjustment are discussed in details.
200 TW (pulse duration 45 fs at energy 9 J) peak power has been achieved experimentally using a Cr:forsterite master oscillator at 1250 nm, a stretcher, three optical parametrical amplifiers based on KD*P (DKDP) crystals providing 14.5 J energy in the chirped pulse at 910 nm central wavelength, and a vacuum compressor. The final parametrical amplifier and the compressor are described in detail. Scaling of such architecture to multipetawatt power is discussed.
Optical parametric amplification of broad-band pulses in large-aperture KD*P (DKDP) crystals has been studied in experiment. A procedure of adjusting the amplifier for single-shot operation of a pump laser has been developed. Peak power of compressed signal radiation (pulse duration 45 fs at energy 9 J) was 200 TW. This considerably exceeds the record level obtained so far in lasers based on optical parametric chirp pulse amplification.
This paper presents the results of experimental investigations into the interaction of laser pulses of femtosecond duration with aerosol having various composition (aqueous aerosol, dye solution with embedded nanoparticles), as well as with individual particles in the case of two-photon induced stimulated fluorescence. The acoustic method was employed to study the decay of the energy of the filament generated at different focusing, as well as the transmittance of the filament energy as it passed through the aerosol layer.