Photorefraction of Pb-doped tin hypothiodiphosphate

Photorefractive properties of deliberately lead-doped tin hypothiodiphosphate (Sn2P2S6, SPS) are investigated. In contrast to nominally undoped crystals, the space-charge gratings are formed by charge species of only one type, holes, what ensures a high beam-coupling gain in the steady-state. No optical sensitization is needed for the recording with near infrared light, but a photorefractive sensitivity does not extend beyond a wavelength of 0.9 μm. Like for some other SPS crystals, in SPS:Pb the effective trap density was found to be intensity dependent in the red spectral range.