Volume holographic recording of narrow-band information

Abstract

Volume holography is gaining renewed interest sparked by the need for denser and faster information storage paradigms as well as for wavelength manipulation in communication networks and laser beam shaping. Conventional approaches used for theoretical analysis of the volume holographic processes are not adequate when complicated wavefronts are involved since they can only deal with elementary cases, such as plane waves. The present work exploits the fact that most holographic systems involve several waves that may propagate at large angles but each of them contains only a relatively narrow spatial frequency band. Introducing a narrow band approximation facilitates the theoretical treatment of architectures comprising several wave fronts propagating at large angles. The combination of this approximation with a generalized description of volume holography leads to a theoretical framework that is suitable for the analysis of most holographic systems encountered in the applications indicated above. A numerical study demonstrates the power of the method and the existence of a coherent motion blur that was predicted recently. The study indicates the effectiveness of volume holography for beam shaping and leads to some disturbing consequences related to bit-oriented information storage.