Sub-millisecond phase contrast wavefront sensor based on an optically addressed ferroelectric liquid crystal spatial light modulator

摘要

A sub-millisecond wavefront sensor based on a non-linear Zernike filter is described. The sensor's key element is an optically addressed spatial light modulator (OASLM). The OASLM is composed of ferroelectric liquid crystal and an amorphous silicon carbide photo-conducting film. The OASLM is placed into the focal plane of a Fourier filtering system. The sensor operates with circularly polarized input light. For the high intensity (zero order) spectral component the deviation of the ferroelectric liquid crystal director by π/4 (45°) results in a π/2 phase shift. This provides wavefront phase distortion visualization similar to a conventional Zernike filter. The registered characteristic response time of the sensor is near 0.2ms for light intensity on the order of 100nW.