The Study On Zernike's Phase Contrast Wave-front Sensing Technology

Starting from the principle of spatial filtering, the theoretical formulas of Zernike's phase contrast wave-front sensing technology are deduced, and the small phase distortion limitation in the traditional phase contrast method is relaxed. In the general phase condition, the output intensity of the differential phase contrast wave-front sensor presents a point to point sine function's relationship with the input phase in its pupil, which means that there is a huge potentiality to use it as a high resolution wave-front sensor in the adaptive optics (AO) system. In order to the check the measuring error of the sensor, the phase is reconstructed according to the output intensity of the differential sensor in the ideal phase shifting condition and the comparison between it with the input phase is also made by means of numerical simulation. It is demonstrated that the measuring error is acceptable when the amplitude of the input phase distortion is small, and it also relates with the accuracy of the phase unwrapping when the amplitude of the phase distortion is large. A differential phase contrast wave-front sensing system based on an optical addressed ferroelectric liquid crystal spatial light modulator (OA-FLCSLM) is introduced, different from the traditional phase contrast method which is highly sensitive to the wave-front tilt. At last, a comparison of some important performance characteristics between the phase contrast method with several other kinds of traditional wave-front sensing technology is made.