Study on high precision Shack-Hartmann wave sensor

Shack-Hartman wave sensor is applied widely in wave-front process with real-time and stable advantages. To increase the testing accuracy of Shack-Hartman sensor, the centroid testing accuracy must be increased first. But the centroid testing accuracy is decided by the detector performance, which is at the system focal plane. The testing accuracy will decrease with detector pixel size increasing. Based on micro-scanning system, the detector in Shack-Hartman wave sensor will receive four images of the wave-front under test. They are rebuilt to a single image after digital image procession. The centroid is calculated and wav-front is rebuilt by wave-front processor. The pixel distance is subdivided to 1/N along X and Y direction respectively with micro-scanning system. N*N is the detected image frames. The sub-pixel shifting images are rebuilt to a whole image after digital image procession. And the resolving power is realized to be increased finally. With application of micro-scanning in Shack-Hartman wave sensor, the system error due to detector accuracy in Shack-Hartman will be decreased. Consequently, the requirement on detector will be decreased. The resolving power of detector is improved greatly. As a result, the image quality testing accuracy of Shack-Hartman wave-front is improved. The image quality testing accuracy of traditional Shack-Hartman wave-front sensor will be increased within the original field of view. And the application range of Shack-Hartman wave sensor is also enlarged effectively.