<title>Elementary Spatial Filtering With Magneto-Optic Light Modulators</title>

Abstract

The application of a newly developed transmission-mode magneto-optic spatial light modulator to optical image processors is being examined. This high speed, reusable, electrically addressable spatial light modulator can provide a non-volatile random access interface for optical processor input and output. The light modulator employs a magnetic irongarnet thin film on a transparent nonmagnetic substrate. The magnetic film is divided into an array of separate magnetically bistable mesas. Plane polarized light transmitted through the array of mesas and the polarization analyzer is spatially modulated by the Faraday effect. This paper describes the operation of the new magneto-optic spatial light modulator in simple tests in the input plane, transform plane and output plane of optical image processors. Test patterns written into the object input plane produce Fourier transforms having most of their energy. lying near the X and Y axes. Operation of the spatial light modulator in the Fourier plane was demonstrated by reproducing the classic Abbe-Porter mesh component deletion experiment, and by obtaining edge-enhancement images. The spatial light modulator. was also tested as a compact output image scanner in the output plane. Image addressing is particularly straightforward in applications requiring only binary light modulation.