An improved phase diversity wavefront sensor based on the altered exposure time of camera

摘要

Since the phase diversity (PD) wavefront sensor has the advantages of simple structure and high light energy utilization, it is one of most attractive wavefront detection tools. The accuracy of retrieval wavefront depends on the precision of the detective intensity distribution of the CCD camera. However, limited by manufacture craft, the noise data are inevitably recorded, so CCD has only good performance in fixed dynamic ranges. In this paper, we propose a simple modified phase diversity wavefront sensor based on the altered exposure time of camera to improve the dynamic ranges of CCD. The two images are taken under normal exposure time and saturated exposure time of CCD, and then they are stitched to form a perfect image including accurate high space frequency and low space frequency information. Under same signal to noise ratio a comparison between the improved phase diversity wavefront sensor and the traditional phase diversity wavefront sensor is made by using simulation. The results show that this method can significantly enhance the retrieval wavefront accuracy.