Abstract

A light efficient technique for generating large (100 × 100+) arrays of uniform intensity spots of good contrast is proposed. One application of spot arrays such as these is as power supplies for optical logic devices in 2-D optical computing architectures.¹ Previously described spot array generation techniques may exhibit significant spot nonuniformity when producing large spot arrays. This nonuniformity is due to quantization and fabrication errors in the transition locations, phase-depth errors, and computational errors.² This spot generation technique utilizes phase gratings to produce small spot arrays (<20 × 20) whose extra orders are then spatially filtered. This small spot array image is then multiply imaged via another phase grating to produce the large spot array. Since each grating need only produce a small number of spots, the design computation and fabrication constraints are simplified. An experimental demonstration of this technique for a 77 × 77 array is presented as well as a discussion of potential limitations.

© 1988 Optical Society of America