LIGHT-MODULATION FROM CROSSED PHASE GRATINGS

A new device, consisting of two phase gratings oriented with a small a ngle between their grating grooves, acts as a variable-profile diffrac tion grating that produces variations in the diffraction orders as the illumination region is moved across the device. Combinations of phase gratings that optimize the effect and act as passive light modulators are given. An experiment that demonstrates the principle is described . (C) 1998 Optical Society of America.