Nonuniformity in hologram diffraction efficiency from time-constant error in the recording schedule

Holograms recorded in materials such as photorefractive crystals exhibit exponential decay upon subsequent exposure to light. To ensure uniform diffraction efficiencies of multiple holograms, one needs to write according to a recording time schedule that can be calculated from the writing and the erasing time constants of the material. We analyze how errors in the time constants affect the uniformity of the diffraction efficiency in multiple holograms. For good uniformity to be maintained, the accuracy of the erasing time constant needs to scale inversely proportional to log M, where M is the number of exposures, whereas error in the writing time constant causes a finite error that does not increase with M. (C) 1996 Optical Society of America