Effect of Grating Spacing on Response Time and Sensitivity in Photorefractive Materials at Large Modulation Depth

Photorefractive response time and photorefractive sensitivity are two important parameters characterizing photorefractive materials. We study theoretically the effect of the grating spacing on these parameters at large modulation depth in the absence and presence of an applied electric field for some of the most promising photorefractive materials, namely, LiNbO3, KNSBN, SPS, BGO, and GaAs. We find that the response time increases with increasing grating spacing for LiNbO3 and KNSBN, whereas the response time decreases with increasing grating spacing for SPS, BGO, and GaAs. The photorefractive sensitivity is mainly affected by the mobility–lifetime product in the presence of an applied electric field.