Cgh Alignment Technique

The testing methods of the aspheric surface is one of the key technologies in optical testing, Testing aspheric surface with computer-generated holograms(CGH) is a major breakthrough to this problem. But the alignment technology of the CGH is still a major problem. In this paper, we will do some research about this problem.First of all, we discussed the basic concept of the aspheric and the commonly testing methods, and outlined their advantages and disadvantages. It focused on the principle of the testing method of the aspheric with CGH and the problems which we need to know, it also analyzed and summarized the error sources in this testing method, and illuminated the importance of the elimination of the error and the need for calibrating the CGH. In this article, we also discussed the commonly alignment methods of the CGH, and analyzed their advantages and disadvantages. We also calculated and analyzed the relationship between the value of adjustment and the aberration. We made a simulation to the CGH, studied the effects of the aberration which caused by changing the degrees of the freedom,and analyzed the sensitivity of the adjustment by changing the incident angles. Finally, we made some experiments and used the experimental datas to further illustrate the impact of the CGH position, and gave the distinguish limits of the interferograms.