Yu. N. Panchenko

High-power excimer laser systems

Two-high power excimer laser systems with square (25 × 25 cm) and circular (with a diameter of 40 cm) cross sections of the output laser beam are described. The first (second) system consists of four (five) excimer lasers. The experimental results on the generation of the high-quality high-power laser pulses are presented. Laser beams with a pulse duration of 1–250 ns, a divergence of 0.01 mrad, a spectral line width of 0.01 cm−1, and a pulse energy of up to 330 J are obtained.

Influence of the gas mixture composition on pumping energy dissipation in a XeF(C-A) amplifier of the hybrid femtosecond laser system THL-100

The influence of the composition of a gas mixture in a XeF(C-A) amplifier of the THL-100 hybrid femtosecond laser system on the main channels of energy loss is studied via numerical simulation. It is shown that an increase in the N2 buffer gas pressure from 100 to 760 Torr increases the fraction of absorbed energy transferred to the upper laser level XeF(C,ν = 0), while an increase in the XeF2 partial pressure increases energy loss in collision quenching of the XeF(B, C) states and reduces the energy transferred to the XeF(C,ν = 0) state.

Numerical Method of Cavity Adjustment by the Output Beam Image

Results of numerical and experimental studies of the control of optical elements of a KrF laser cavity by use of the image processing method are presented. Different methods of beam image binarization for determining the boundary dimensions and flattening the distribution of its radiation intensity are considered. Conditions allowing one to accelerate the process of dispersive cavity adjustment in the automatic regime of laser operation and to restore the initial parameters of the output beam with an accuracy of up to 5% are determined.

Broadening of the Spectra of Femtosecond Laser Pulses upon Passing through Optical Materials

Results from studying the conditions under which spectra generated by a 50 fs pulse from a Ti:Sa setup broaden at a wavelength of 475 nm are described, along with how to compensate for the accompanying positive dispersion. It is shown that the width of the spectra grows from 5 to 15 nm when the thickness of K8 glass is optimal. Pulse recompression with a spectral width of a 12.2 nm is achieved, along with a pulse duration of 22.6 fs.

A wide-aperture x-ray source with high intensity and uniformity of radiation

The results of experimental research on an x-ray source intended for preionizing the laser mixture in wide-aperture electric-discharge excimer lasers are presented. An experimental prototype of the source in which an x-ray radiation pulse is formed in an inverted-type vacuum diode during braking of accelerated electrons in a tantalum foil has been developed. It is shown that the use of a metal-dielectric cathode allows generation of x rays with nonuniformity of the intensity distribution within limits of 10% at an energy of quanta no higher than 55 keV and a radiation exposure dose 160 mR.

Formation of highly coherent radiation in a wide-aperture exciplex laser

The results of experimental investigations into the feasibility of improving the spatial and temporal coherence of the radiation of aXeCl laser with a 16×12 cm output aperture and a pulse output energy up to 150 J are given. It is shown that in the injection-locked mode, 90% of the output energy can be emitted in a narrow spectral line. An unstable resonator with mirrors small in size and generalized parameters gi>1 allows a near-diffraction-limited beam divergence to be obtained.

On the spectral brightness of the SRS radiation excited in metal vapors by a XeCl laser

Results of an experimental study of the spectral brightness of SRS radiation excited in lead vapors with wide-band (two lines 3-cm−1 wide) and narrow-band (0.1 and 0.01 cm−1) radiation of a XeCl laser with angular divergence close to the diffraction limit are presented. It is shown that the width of the SRS line is limited by the Doppler broadening, the SRS efficiency for a narrow-band beam increases by a factor of two, and the divergence of SRS radiation, which is characterized by the fraction of energy found within the diffraction angle, exceeds the divergence of pump radiation by a factor of 3 to 4.