Photoinduced Absorption in Bismuth Titanate Crystals on Nano- and Picosecond Excitation

The peculiarities in the induced absorption of bismuth titanate (Bi12TiO20) crystals upon their irradiation by high intensity nano and picosecond pulses with a wave length of 532 nm have been studied. The relationship between the photochromic effect and radiation intensity at the fixed radiation dose in con ditions of pulsed laser excitation has been established. A threshold character of the relationship between the photochromic effect and intensity has been found for the first time. A phenomenological model making it possible to explain qualitatively the dynamics of the trapping level population process has been proposed