METHOD OF PRODUCING NONLINEAR MATERIAL FOR INVERTING WAVEFRONT Russian patent published in 1995 - IPC

FIELD: quantum electronics. SUBSTANCE: lithium fluoride crystal with hydroxyl additive ions is doped additionally by hydroxyl additive ions till achieving 2-44 cm^-1. absorption coefficients at 2,68 mcm wavelength. The crystal after being radiated by ionizing radiation till achieving 2,5·10³-1,25·10⁵ kl/kg doses at -196 to -40 deg C, was subject to laser radiation at wavelength in absorption range of F₂-centers at power density of 5·10⁴-5·10⁸ W/cm³ and total energy density of 11 J/cm². and more. Lower boundary of power density range of radiation incident onto the crystal is provided by start point of two-quantum ionization processes. Top boundary is provided by threshold of crystal optical damage under effect of nanosecond pulses. Spectral range of crystal working waves is broadened to short wave range. EFFECT: reduced power consumed for creation of dynamic diffraction grating; increased set of frequencies of waves to be inverted. 1 tbl