Alignment of off-axis optical system with multi mirrors using derivative of Zernike polynomial coefficient

The precise alignment of multiple element large optical system is a challenging task. In order to increase the alignment process efficiency, computer aided alignment methods utilizing Zernike polynomial coefficients have been developed over the last few decades. Recently, differential wavefront sampling(DWS) algorithm revealed that derivative information about the wavefront is a very useful to separate wavefront coupling effect between optical elements of the target system. We compared the alignment performance of the DWS, sensitivity table method and merit function regression method. Even though DWS showed the best performance in simulation, it revealed weak points in terms of high sensitivity to the experimental conditions when applied to the real alignment of Korsch type optical system. In this paper, we explain three different alignment algorithms and discuss the problems in DWS method under current experimental situation, and show the alignment result for Korsch type optical system using merit function regression method.