High-diffraction-efficiency pseudorandom encoding

Pseudorandom encoding (PRE) is a statistics-based procedure in which a pure -phase spatial light modulator (SLM) can yield, on the average, the prescri bed diffraction pattern specified by the user. We seek to combine PRE with the optimization of an aperture-based target function. The target function is a fully complex input transmittance, unrealizable by a phase-only SLM, t hat generates a prescribed light intensity. The optimization is done to inc rease the diffraction efficiency of the overall process. We compare three o ptimization methods-Monte Carlo simulation, a genetic algorithm, and a grad ient search--for maximizing the diffraction efficiency of a spot-array gene rator. Calculated solutions are then encoded by PRE, and the resulting diff raction patterns are computer simulated. Details on the complexity of each procedure are furnished, as well as comparisons on the quality, such as uni formity of the output spot array. (C) 2000 Optical Society of America [S074 0-3232(00)01002-4] OCIS codes: 050.1970, 090.1970, 220.4830, 230.6120.