Design Of Optical System For High-Density Holographic Data Storage

The information technologies have been fast developing and strongly demanding for the information storage technology. Owing to the high density, mass capacity, and fast data transfer rate, the holographic data storage (HDS) technology has become one of the potential new types of information storage technologies. The holographic disc storage technology, which has the properties of simplicity in optical read-write head and the compatibility with existing disc system, is more suitable for the application of high-density and mass-capacity data storage. Thus, research on holographic disc storage systems has practical significance.This paper is focused on the design of the optical system of HDS. The aims are to implement 1:1 pixel-matching of high resolution data pages (1024×768) between SLM and CCD, and to design a compact holographic disc storage system with optimized optical and mechanical structure, thus, to help with putting the holographic data storage technology into practice.We reviewed first the fundamental theory on volume holography (mainly the coupling-wave theory), and the mechanism of holographic storage materials (mainly photorefractive crystals and photopolymers). Based on the above fundamentals, the importance of Fourier transform holograms for holographic storage is described. The multiplexing techniques of holographic disc storage are briefly introduced, especially, the spatio-angularly multiplexed (SAM) holographic disc storage scheme is discussed in detail. The aberration theory of optical design is also reviewed.In the design of holographic disc storage system, we first proposed an optimized reflection configuration for SAM Fourier-transform hologram storage. Then we designed and manufactured an asymmetrical Fourier transform lens pair, which matched the parameters of SLM and CCD and the system requirements. In order to achieve 1:1 pixel-matching of high resolution data pages (1024×768) between SLM and CCD, the two lenses were designed and optimized in an iterative manner, and the combination of them reached satisfactory results with eliminated aberrations that can meet the design requirements. More importantly, the tolerance analysis of optical...