Lilya G. Geiko

Optical properties of a nonlinear LiInS{sub 2} crystal

The linear and nonlinear optical properties and the radiation resistance of a LiInS{sub 2} single crystal are studied. Phase matching conditions are calculated for the first time for a LiInS{sub 2} crystal. (nonlinear optical phenomena)

Conditions of Phase Matching for the Second Harmonic Generation with ZnGeP2 Crystals

The reasons for the discrepancy between the available experimental data on the phase-matching conditions for the second harmonic generation with nonlinear ZnGeP2 crystals are elucidated. The calculated and experimental phase-matching angles agree for crystals at room temperature and low pumping radiation power. Simultaneous solution of the consistent shortened equations for the complex amplitudes and of the heat conductivity equation demonstrates that pumping by intense laser beams causes the angles phase-matching to decrease by 5–25° and the long-wavelength edge of phase matching for doubled frequency of CO2-laser radiation to increase from 10.32 to 10.8 μm. An excess decrease in the angles phase-matching by 1–3° is due to the asymmetry of the thermal processes caused by the birefringence.

Phase matching and optical properties of LiInS2 nonlinear crystal

Results on investigation of linear and non-linear optical properties, damage threshold and potential efficiencies of biaxial LiInS2 crystal are represented. Transmission range is 0.4 - 12.5 micrometers at the 0.1 level and 0.5 - 11.0 micrometers at the 0.5 level. Typical absorption coefficients are as low as 0,1 - 0,25 cm-1 at the maximum transmission range 1.0 - 8.0 micrometers and 1.1 - 2.3 cm-1 at the CO2 laser wavelengths. Coefficients of second order non-linear susceptibilities are d31 equals 6.2, d32 equals 5.4 and d33 equals 9.8 pm/V, but damage threshold is as high as 120 - 130 MW/sm2 for 36 ns pulses at 9.55 micrometers . The phase-matching is estimated with using of determined Sellmeier coefficients. It is represented in graphic form so as fields of SHG efficiencies. It is shown that LiInS2 can be used in middle IR OPO pumped by Cu-vapor laser, group-velocity phase matching take place in wide spectral range for sum- and difference-frequency generation of visible, near and middle IR lasers including SHG of 3 micrometers Er laser.

Laser frequency converters for Universal Lidar system

We present phase-matching conditions and widths, results on estimations of frequency conversion efficiencies, and other potential characteristics of frequency converters.

Simulation of lidar sounding of the atmospheric meteoparameters in the spectral window 2 to 2.4 μm

Sum frequency generators of Er3+:CaF2 ((lambda) equals 2.76 micrometers ), Er3+:YAG ((lambda) equals 2.94 micrometers ), and cw CO2 lasers with ZnGeP2 single crystals has been developed to enlarge the possibilities of spectroscopic systems based on CO2 lasers. The generated spectra overlapped the ranges from 2.0 to 2.4 micrometers , which coincide with the two main atmosphere transparence windows. The energy efficiency of sum frequency generation is about 3% at phase-matching angle of 52 degree(s). The results of numerical simulation of the high-altitude profiles definition of atmospheric meteorological parameters by differential absorption lidar system working in eye-safe spectrum range at 2 micrometers has shown, that errors of the temperature and humidity profiles restoring have reasonable values in all altitude range 0 - 2 km.