Abstract

Holographic elements have been fabricated in dichromated gelatin to generate arrays of up to 56 × 56 focusing beams with over 90% diffraction efficiency. Spot diameters within 10% of the diffraction limit for f/5 lenses at visible and near-IR wavelengths have been achieved. Compensation for the aberrations introduced by the wavelength change between hologram construction and replay is achieved by forming the hologram with two optimized spherical wavefronts. These wavefronts are chosen by modeling the hologram with a ray-tracing program which includes efficiency calculations and the effects of thickness and refractive-index changes between construction and replay. These holograms can be used to illuminate arrays of optical logic gates. Holograms for interconnection of arrays have also been made as both space-variant and space-invariant devices. A hologram which provides a fanout of four to nearest neighbor pixels with an efficiency of 40% (10 ± 0.2%/beam) has been constructed. This hologram operates in the Fourier transform plane of the input pattern and is, therefore, space-invariant.

© 1988 Optical Society of America