Multiphoton Photoconductivity and Laser Induced Damage in Alkali-Halide Crystals Under Picosecond Pulses from YAG:Nd Laser and its Harmonics

Abstract

The results are presented of studying photoconductivity induced by picosecond pulses of the second, third, and fourth harmonics of YAG:Nd-laser in KCl, NaCl, KBr, KI crystals. The processes of multiphoton photoexcitation of nonequilibrium carriers are revealed up to the 4-th order and the corresponding multiphoton absorption coefficients are measured. Drift mobility of thermalized nonequilibrium electrons is measured. The role of multiphoton absorption in laser-induced damage in crystals is discussed. With a view to elucidating the role of impurities (inclusions) in the laser induced damage in alkali-halide crystals in the picosecond region, impurity photoconductivity is studies depending on thermal treatment of crystals.