Encoding technique for design of zero-order (on-axis) Fraunhofer computer-generated holograms

摘要

Diffractive optical elements able to generate zero-order (on-axis) distributions with phase as well as amplitude distributions are described. The proposed elements are surface relief plates, i.e., phase-only elements, that are based on the concept of computer-generated masks followed by common etching processes. The encoding method assumes fixed spatial partitioning of the cell and a phase-only value allocated to each subelement. The reconstructed amplitude and phase distributions contain imperfections (noise) resulting from the encoding process. Methods of error reduction and improvements are provided. (C) 1997 Optical Society of America.