A novel method for measurement of the refractive indices of transparent solid media using laser interferometry

TL;DR

This paper introduces a new laser interferometry-based method for non-contact measurement of the refractive indices of transparent solids, validated through experiments with glass samples.

Contribution

It presents a novel interferometry technique and a simple laser-based method for measuring refractive indices, with derivations and experimental validation.

Findings

Experimental RI values are consistent across methods.

Methods are suitable for undergraduate laboratories.

Results align with known glass RI values.

Abstract

A novel method is proposed to measure the refractive indices (RIs) of the materials of different transparent solid state media. To exploit the advantage of non-contact measurement laser beam interferometry is used as an effective technique for this purpose. The RIs of materials are also experimentally determined with the aid of another laser based simple method. The derivations of the working formulae for both the methods are presented. The experimental values of RI of any glass sample found by the different methods are consistent with each other and fall within the range of known values of RI for glass. Both types of experiments can be set up rather easily in an undergraduate laboratory. They can supplement other methods of finding refractive index like, for example, methods based on the use of a spectrometer.