Light induced absorption and optical sensitizing of Sn2P2S6:Sb

Photorefractive sensitivity of antimony doped Sn2P2S6 can be increased at ambient temperature by preexposure of the sample with an intense auxiliary light beam. It is shown that the largest enhancement of sensitivity occurs if the photon energy of preexposure light is close to the crystal bandgap, it decreases gradually with increasing wavelength. The preexposure gives rise also to a pronounced transient light induced absorption which vanishes approximately one order of magnitude faster than the decay of the sensitized state.