Refractive Index and Thickness Determinations Using a Near-common- and Unequal-path Wavelength Scanning Interferometer

• Main Authors: Tzu-Lung Lin, 林志龍
• Other Authors: Shyh-Tsong Lin
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/pyb27v

碩士 === 國立臺北科技大學 === 光電工程系研究所 === 95 === A new and simple interferometer based on three designs, near-common-path, unequal optical-path-length, and rotating analyzer, is proposed for refractive index and thickness of a transparent plate determinations. These designs make the interferometer with the characteristics of high stability, high sensitivity, compact optical setup, and real time measurement. In the experimental process, a tunable laser diode was adopted as the laser source, and then measure three known parameter of the transparent plate, respectively. The variation of the wavelength of the laser beam can be measured by wavelength meter, and then the variation of the phase of the interference signal can be measured by lock-in amplifier. The measured data are substituted into the specially derived equations, and the refractive index and thickness of a transparent plate are determined. The analysis the errors of measurement are discussed. And the experimental results from applying the setup agree the validity of this interferometer.