Grating compressor optimization aiming at maximum focal intensity of femtosecond laser pulses.

It is shown that the optimal geometry of a Treacy compressor is the full-aperture compressor, in which the beam size at the first diffraction grating is equal to its length. Despite the energy losses and greater size of the focal spot, such a compressor provides considerably higher (by 1.5-2 times) focal intensity than an energy lossless compressor.

Post-compression of powerful femtosecond pulses after second harmonic generation.

A proof-of-principle experiment of highly efficient (38%) second harmonic generation was implemented at a ∼1 / intensity of a 45 fs pulse in a composite nonlinear sample-a 1 mm KDP crystal glued onto a 1 mm fused silica substrate. The attenuated replica of the second harmonic pulse (455 nm) was compressed down to 28.6 fs by means of dispersive mirrors, with a significant reduction in both the wings and the far temporal contrast.

Pulse fluence noise dynamics at free-space propagation.

The dynamics of fluence noise of an optical pulse at free-space (e.g., vacuum) propagation has been studied.

Upgrading the front end of the petawatt-class PEARL laser facility.

A new front-end laser system with optical synchronization of chirped femtosecond and pump pulses for the petawatt laser complex PEtawatt pARametric Laser (PEARL) has been developed. The new front-end system provides a broader femtosecond pulse spectrum, temporal shaping of the pump pulse, and a significant increase in the stability of the parametric amplification stages of the PEARL.

Small-scale fluctuations of laser beam fluence at the large B-integral in ultra-high intensity lasers.

Analytical expressions for the spatial spectrum of fluence fluctuations of a laser pulse propagating in a medium with Kerr nonlinearity have been obtained. It is shown that inhomogeneities with a spatial scale much larger than the critical scale of self-focusing grow insignificantly even at large values of the B-integral. Experiments using BK7 glass and a KDP crystal as a nonlinear medium confirm the obtained theoretical results.