Pseudorandom encoding of complex-valued functions onto amplitude-coupled phase modulators

Pseudorandom encoding is a method of statistically approximating desired complex values with those values that are achievable with a given spatial light modulator. Originally developed for phase-only modulators, pseudorandom encoding is extended to modulators for which amplitude is a function of phase. This is accomplished by transforming the phase statistics to compensate for the amplitude coupling. Example encoding formulas are derived, evaluated, and compared with a noncompensating pseudorandom-encoding algorithm. Compensating algorithms encode a smaller area of the complex plane and can produce more noise than is possible far arbitrary pseudorandom algorithms. However, the encoding formulas have greatly simplified numerical implementations. (C) 1998 Optical Society of America.