Studying of refractive index measurements in reflected light

TL;DR

This paper compares two refractometry methods based on reflected light, analyzing their accuracy, error sources, and advantages for measuring the refractive index of various materials using laser radiation.

Contribution

It introduces and experimentally evaluates two refractometry methods based on Fresnel and Brewster angle principles for improved accuracy in refractive index measurement.

Findings

Measurement accuracy up to 4 significant digits

Identification of key error sources in both methods

Advantages for measuring solid, thin-film, and absorbing materials

Abstract

Two methods of refractometry in reflected light from optical surface of samples are considered and studied experimentally. Methods are grounded on results of Fresnel theory of concerning light reflectivity at near normal incidence and Brewster angle. Sources of errors for both methods were considered and possibility of measuring of the refractive index with application of laser radiation with accuracy to within 4th sign was shown. Advantages of described methods concerning requirements to preparation of samples to refractive index measurement of solid, thin-film and absorbing materials are scored.