ABSORPTION EFFECTS IN PHOTOREFRACTIVE VOLUME-HOLOGRAPHIC MEMORY-SYSTEMS .2. MATERIAL HEATING

We consider how absorption-induced material heating alters the phase p rofile, the scale, the orientation, and the Bragg matching of volume h olograms. We derive theoretical equations that consider the prisming, the lensing, and the Bragg mismatching that occur during material heat ing and compare these with experimental observations. From our Bragg-m ismatching considerations we show how both read beam angle and wavelen gth need to be dithered for proper compensation of volume holograms fo r material-heating effects. Our results indicate that material heating in volume-holographic memory systems poses a severe threat to system performance. This threat is shown to be very significant in Fourier pl ane holograms but only moderately significant in image plane holograms . (C) 1996 Optical Society of America.