Crosstalk limited storage capacity of volume holographic memory

Abstract

Angularly multiplexed volume holograms1 are considered for use in optical memory systems where compactness and high storage density are desired features. In such a memory system, an object beam containing a page of information is recorded in association with a uniquely oriented reference beam in a volume recording material such as photorefractive crystals. The procedure is repeated with different sets of object and reference beams to yield a volume memory in which a particular page of information can be uniquely accessed by reading the hologram with the corresponding reference beam. The largest amount of information that such a system can store is upper-bounded by the geometric factor O(V/λ3) where V is the volume of the holographic medium and λ is the wavelength of light.2 A tighter upperbound can be derived by considering the limitations of the medium.3 In this paper, we consider the storage density limiting effects due to crosstalk between the stored pages during readout. We review some earlier work done in this area4 and present new theoretical and experimental work that characterizes the storage capacity limitations from the crosstalk.