Phase‐conjugate Michelson interferometers for all‐optical image processing and computing

When the mirrors of a conventional Michelson interferometer are replaced by phase‐conjugate mirrors, the resulting interferometer displays dramatically altered behavior which makes it ideally suited to performing important operations in parallel optical image processing and optical computing. The phase‐reversing property and real‐time response of the phase‐conjugate mirrors make this type of interferometer much more immune to spatially uniform and nonuniform phase distortions, both static and dynamic. Phase‐conjugate interferometers are remarkably stable, sensitive only to real amplitude disturbances or information in the arms, and they readily display the subtraction, addition, intensity inversion, spatial differentiation and, in certain cases, temporal differentiation of two‐dimensional optical images.