title: Instrument for measuring small angles by use of multiple total internal reflections in heterodyne interferometry.
abstract: A new instrument for measuring small angles by use of multiple total internal reflections in heterodyne interferometry is presented. With this instrument we can achieve a small rotation angle only by measuring the variation in phase difference between s- and p-polarization states. To improve its sensitivity we increase the number of total internal reflections by using two parallelogram prisms instead of two right-angle prisms. The angular resolution of the new instrument is better than 2.2 x 10(-6) rad over the measurement range -2.12 degrees < or = theta < or = 2.12 degrees for 20 total-internal reflections. The experimental results and the theoretical curve are in good agreement.
authors.affiliation: Department of Electro-Optical Engineering, National Huwei University of Science and Technology, 64 Wunhua Road, Huwei Yunlin 632, Taiwan, China. mhchiu@nhust.edu.tw
authors.forename: Ming-Hung
authors.initials: MH
authors.lastname: Chiu
authors.forename: Shinn-Fwu
authors.initials: SF
authors.lastname: Wang
authors.forename: Rong-Seng
authors.initials: RS
authors.lastname: Chang