Photorefractive beam coupling in tin hypothiodiphosphate in the near infrared.

Infrared recording of phase gratings is investigated in Sn(2)P(2)S(6) crystals by radiation of a Nd(3+):YAG laser (lambda = 1.06 microm) Space-charge formation and hologram recording are dominated by diffusion charge transport. Without an applied electric field, but with preexposure of the sample to incoherent white light, the gain factor exceeds 6 cm(-1) at laser intensities above 50 W/cm(2).