The phase difference between s and p polarization of the light reflected from a material is used for measuring the material's complex refractive index. First, two phase differences that correspond to two different incidence angles are measured by heterodyne interferometry. Then these two phase differences are substituted into Fresnel's equations, and a set of simultaneous equations is obtained. Finally, the equations are solved by use of a personal computer by a numerical analysis technique, and the complex refractive index of the material can be estimated.

No abstract

A new method for measuring the refractive index is presented. First, the phase difference between s and p polarizations that is due to the total internal reflection is measured by heterodyne interferometry. Then, substituting this phase difference into the Fresnel equations, we can obtain the refractive index of the test medium.

A method based on a specific quasi-common-optical-path (QCOP) configuration for two-dimensional displacement measurement is presented. The measurement system consists of a heterodyne light source, two-dimensional holographic grating, specially designed set of half wave plates, and lock-in amplifiers. Two measurement configurations, for single and differential detection, are designed. The sensitivity, resolution and nonlinear phase error of the differential detection type are better than those of the single detection type. The experimental results demonstrate that the QCOP interferometer has the ability to measure two-dimensional displacement while maintaining high system stability.

No abstract