Analysis of the Optical Path Function and Aberration Coefficients on Free-From Surface of Double Grating

• Main Authors: Chang-Teng Liu, 劉常登
• Other Authors: Cheng-Hao Ko
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/44304605899705610113

碩士 === 國立臺灣科技大學 === 自動化及控制研究所 === 104 === A double ellipsoidal grating (DEG) system with variable grating line spacing is presented, which includes the analysis of the optical path function and aberration coefficients. Fermat’s principle is applied to relate the coordinate systems between the two ellipsoidal gratings. Aberrations on the image plane can be calculated based on this analysis. However, the aberrations on the image plane for a DEG system is unable to be adjusted. In order to reduce the aberrations on the image plane for a double grating system, we construct a double free-form-surface grating (DFSG) system with variable grating line spacing. The aberration coefficients of the optical path function of a DFSG system are compared to those of a DEG system in order to construct the coefficients of free-form grating surface profile and variable line spacing. By using Fermat’s principle, the coordinate transformation between the two gratings is obtained. Aberrations on the image plane can be expressed as the grating surface profile coefficients and the grating line spacing coefficients. By adjusting these two sets of coefficients, we are able to reduce the aberrations on the image plane.