Optical symbolic substitution: system design using phase-only holograms.

Symbolic substitution is a method for manipulating binary data that depends on both the value of the data and its spatial location to realize logical operations. A substitution system requires only a pattern recognizer, a nonlinear device, and a pattern substituter. Using classical optical elements and phase-only holographical elements, it is possible to construct optical systems for both recognition and substitution. Systems using one or two holographical elements are presented, and procedures for designing the elements are also discussed.