V.I. Chizhikov

Optical properties of lithium indium selenide

Conditions of growth of LiInS2 and LiInSe2 crystals with high optical quality are studied. Data on the dispersion of refractive indices in red-phase LiInSe2 crystals are presented. Possible nonlinear three-frequency processes in LiInS2 and LiInSe2 crystals used for SHG and OPO are analyzed. Potentials of these crystals for application in OPO devices are shown.

Optical properties of thallium mercury iodide

We investigated the growth conditions and obtained Tl4HgI6 nonlinear crystals of red and black phases. We also measured the dispersion of the black-phase crystal refractive indices and analyzed possible nonlinear three-frequency processes.

Phase-matching and femtosecond difference-frequency generation in the quaternary semiconductor AgGaGe5Se12.

We present data on the linear (transmission, index of refraction) and nonlinear (second-order susceptibility) optical properties of the quaternary semiconductor AgGaGe5Se12 with orthorhombic symmetry--a solid solution in the AgxGaxGe1-xSe2 system with x = 0.17. The nonlinear coefficients are estimated from phase-matched second-harmonic generation near 3 microm. After numerical analysis of the phase-matching configurations for three-wave nonlinear interactions, the first experimental results on difference-frequency mixing, producing tunable (4-7.5-microm) femtosecond pulses at a 1-kHz repetition rate, are described. The pulses of only five optical cycles (FWHM = 84 fs) are generated near 5 microm with energy of 0.5 microJ. Because of its higher damage threshold, larger birefringence and bandgap, and greater variety of phase-matching schemes, AgGaGe5Se12 could become an alternative to AgGaS2 and AgGaSe2, more widely used in high-power and specific applications.

Preparation and Structure of AgGa1 – xInxSe2 Single Crystals

AgGa1 – xInxSe2 single crystals grown by the Bridgman–Stockbarger method, using presynthesized charges with x = 0.27, 0.335, and 0.375 are studied by x-ray diffraction (phase analysis, determination of lattice parameters, structure refinement of powdered crystals by the Rietveld profile analysis method, and single-crystal structural analysis). The results suggest that the crystals may contain Se and Ag vacancies. The polarity of the crystals is found to depend on their composition.

Phase-matched second-harmonic generation at 1064nm in quaternary crystals of silver thiogermanogallate

We demonstrate, for the first time to our knowledge, frequency doubling of 1064 nm radiation in sulphide crystals of Ag/sub x/Ga/sub x/Ge/sub 1-x/S/sub 2/ having engineerable birefringence and superior nonlinearity in comparison to oxide crystals.

AgGa 1-x In x Se 2 nonlinear crystals for noncritical phase matching processes

We present the results of investigation of the conditions of growing crystals of solid solutions AgGa1-xInxSe2 of high optical quality for noncritical phase matching processes. The obtained crystals are characterized by low absorption coefficient (0.002 cm-1) and high efficiency of conversion of pumping radiation into second harmonic.