Normal incidence refractometer

摘要

A circularly polarized heterodyne light beam enters a modified Twyman-Green interferometer. An analyzer is used to extract the interference components of two interfering beams reflected normally from the test medium and a reference mirror in the interferometer. The phase of the interference signal is a function of the refractive index of the test medium and the azimuth angle of the analyzer. It can be measured with heterodyne interferometry. Then it is substituted into the specially derived equations from which the refractive index of the test medium is estimated. This method has many merits such as no measurement limitation, a simple optical setup, and easy operation in real-time manner. (C) 2003 Elsevier Science B.V. All rights reserved. [References: 13]