SPATIAL LIGHT-MODULATOR BASED ON THE CONTROL OF THE WAVE-FRONT CURVATURE

A novel device for spatial modulation of the light intensity is considered. The device consists of a freely suspended reflective flexible membrane, optical figure of which is controlled electrostatically by an array of integrated electrodes. The local curvature of the membrane is proportional to the square of the two-dimensional voltage distribution, applied to the array of control electrodes. The light intensity in the near field of the collimated beam, reflected from the deformed membrane is spatially modulated with the depth of modulation being approximately proportional to the membrane curvature. The final intensity distribution in the reflected beam follows approximately the voltage distribution applied to the array of control electrodes. Contrast ratio of 4:1 and resolution of 50 by 50 pixels with response time similar to 1 ms have being obtained with experimentally realized modulator.