Abstract

Acousto-optic (AO) cells have been used to implement Fourier plane filtering in coherent optical processing systems. AO cells have large time-bandwidth products (>1000) and high frame rates (>10 kHz). The optical input to the AO cell at the Fourier plane consists of several plane waves travelling at different angles. The Bragg matching condition limits the input field of view of the AO cell in the Fourier plane. However, the finite acoustic wave vector spread, optical birefringence, and acoustic beam steering have been used to overcome this limitation. In this paper the relation between the SBW product of an image that can be processed by the AO cell and its time-bandwidth product is derived and experimentally verified. The AO cell in the Fourier plane is suitable for image morphology, and it is shown that the time-bandwidth product requirement for this application is independent of the size of the structuring element, enabling a comparatively large space-bandwidth input to be processed.

© 1992 Optical Society of America