Flat-field linearized scans with reflection dichromated gelatin holographic gratings

Abstract

A polygonal holographic scanner that combines a reflection volume hologram on dichromated gelatin with a computer-generated hologram (CGH) is described. Such a scanning system allows for a compact folded version and highly efficient Bragg diffraction into a single order. A design of the scanner with a nonspherical wave front based on ray tracing and the damped least-squares optimization technique allows a flat-field linearized scan to be used. A suitable trade-off between field flatness and position linearity of scan is adopted. The optimized wave front designated by polynomials is encoded into a CGH. Experiments demonstrating the feasibility of this scannner are presented. Additional data on the diffraction efficiency and the spectrally diffracted intensity of the reflection volume gratings are also shown.