Beam Propagation Modeling of the Total Internal Reflection Electrooptic Diffraction Spatial Light Modulators-Finite Interaction Effects

Abstract

The total internal reflection electrooptic diffraction spatial light modulators provide unique performance capabilities for laser recording and optical information processing.1,2,3 Recent devices reported incorporate arrays of 4735 elements on 10 micrometer centers with 256 Mpixel/second data rate.4 These devices share some characteristics of both bulk wave and guided wave optical devices, although a number of characteristics are relatively unique. The input and output coupling are bulk processes enabling essentially lossless coupling over apertures up to several inches. The electrooptic interaction occurs in the vicinity of a single guiding boundary surface illuminated with focussed grazing incidence, resulting in efficient interactions. Modeling of this device is complicated by the combination of effects of anamorphically focussed input beam, spatially inhomogeneous modulation, total internal reflection interference, and diffraction and finite interaction length effects. Also, in the TIR EO SLM detailed spatial characteristics of the optical fields are of primary interest along with interaction coupling efficiencies. Beam Propagation Method5 modeling provides accurate detailed simulation of the modulator behavior and imaging characteristics over a wide range of design and operating conditions. Initial results of this modeling have recently been presented6. In this paper we provide additional results, particularly with respect to modeling finite interaction length effects and imaging.