Abstract

The space-bandwidth requirements on a thick grating in the Fourier plane of a shift invariant coherent optical image processor are analyzed. Based on Kogelnik's relationship for the diffraction efficiency, expressions for the space-bandwidth products (SBWs) of the input image (N) and the point spread function (M) are obtained in terms of grating parameters. It is found that thick ness of the thick grating limits the field of view (FOV) of the input and hence limits the maximum SBW image that it can handle. A thin grating filter scales more readily to larger values of N and M. By angular multiplexing of multiple grating sets the thick grating FOV can be improved. Though the thick grating possesses the extra degree of freedom, higher information storage capacity, and higher diffraction efficiency, the finite FOV limitation makes it less suitable for shift invariant operations via Fourier plane filtering.

© 1992 Optical Society of America