NONLINEAR MONOCRYSTAL OF LITHIUM CHALCOGENIDES OF GENERAL FORMULA LIGAINTE AND A METHOD FOR PRODUCTION THEREOF Russian patent published in 2019 - IPC C30B29/46 C30B11/02 G02F1/355 

FIELD: technological processes.

SUBSTANCE: invention relates to monocrystals of lithium chalcogenides, intended for use in nonlinear optics for implementation of laser visible and near infrared laser radiation adjustment in medium infrared range. Obtained nonlinear monocrystal of lithium chalcogenides of general formula LiGa_xIn_1-xTe₂, where x takes any value from 0.1 to 0.9, having spatial group Id tetragonal symmetry, Z = 4, with elementary cell parameters 6.3295<a<6.398 Å, 11.682<c<12.460 Å and volume of 468.01<V<510.0 ų, characterized by functional parameters: transparency range from 0.76 to 14.8 micron, band gap width of 1.837 eV at 300 K, birefringence values of 0.049 at 2 mcm and nonlinear coefficients d₁₃=3.70 pm/V and d₁₄=48.73 pm/V. Method of producing monocrystal of lithium chalcogenides of general formula LiGa_xIn_1-xTe₂, where x takes any value from 0.1 to 0.9, includes previous synthesis of compound LiGa_xIn_1-xTe₂ of elementary components Li, In, Ga and Te in conditions providing stoichiometric ratio of components, monocrystal growth by a modified Bridgman-Stockbarger method in a vacuum ampoule while providing change ratios of temperature gradients in melt and growing crystal at growth rate from 2 to 10 mm/day and average value of axial temperature gradient from 2 to 3 °C/mm and furnace cooling at rate of about 10 °C/h.

EFFECT: technical result consists in providing the possibility of shifting the absorption edge to a short region (as x increases) in combination with increasing the conversion coefficient by achieving non-critical phase synchronism; expected effect of increasing efficiency of laser radiation conversion using said nonlinear monocrystal is 10–30 % compared to nonlinear LiGaTe₂ monocrystals; at variation of value (x) it is possible to ensure matching of group and phase velocities of laser radiation, at which effective interaction length for femtosecond generation mode is increased, which will provide additional effect of about 10–20 % of efficiency.

2 cl, 3 dwg, 3 ex