Spatial light modulator with output-sign control and self-protective diffraction limiting

摘要

The characteristics of spatial light modulation (SLM) based on a biphoton holographic grating with azobenzene films are studied theoretically and experimentally. The mechanism of SLM originates from trans<-->cis isomerization of the azobenzene molecules induced by two-colored lights. Theoretical results indicate that the SLM output replica can change its sign by varying the intensity of the incoherent light or blocking it. An interesting feature of this SLM model is that it provides a method to limit diffraction efficiencies at high input intensities, which protects photosensors from damage. When an azobenzene-doped polymer film is used, incoherent-to-coherent image conversion and a sign change of a replica of the output image are observed in the experiment. (C) 2000 Optical Society of America [S0740-3224(00)00909-7]. [References: 28]