In the technology of aspheric optical surface measurement, the lateral shearing interferometer had been widely used. In measurement, that how much asphericity it can measure is the fascinating problem. In this paper, based on the structure of lateral shearing interferometer, aspherical optical surface can be measured by phase shifting interferometry, and the depth problem of asphericity in the measurement can be analyzed. Firstly, asphericity of aspherical elements is determined, and the tri-points calculation method is employed. Then, based on the difference between aspherical surface and reference spherical surface, the phase shifting lateral shearing interferograms can be simulated. Finally, the measurement result is obtained by four-step phase shifting interferograms. Through comparing the measurement result with determined asphericity, the measuring scope of asphericity in the lateral shearing interferometry is given. The result is benefit for the decision of measurement solution for aspherical elements.

Date Published: 14 April 2010
PDF: 6 pages
Proc. SPIE 7522, Fourth International Conference on Experimental Mechanics, 75225C (14 April 2010); doi: 10.1117/12.851448

Published in SPIE Proceedings Vol. 7522:
Fourth International Conference on Experimental Mechanics
Chenggen Quan; Kemao Qian; Anand Krishna Asundi; Fook Siong Chau, Editor(s)