Nonlinear refractive-index measurements of glasses using three-wave frequency mixing

TLDR

The study examines how the measured nonlinear refractive index relates to glass structure and composition. The method uses three‑wave mixing with input beams offset by ~60 cm⁻¹, measuring the nonlinear index relative to a standard. The technique provides rapid, accurate nonlinear index measurements that agree with prior data and empirical calculations for 27 glasses.

Abstract

We have developed a rapid and accurate method for measuring the nonlinear refractive index of transparent materials. It is based on a version of three-wave mixing in which the frequencies of the two input beams are adjusted to differ by about 60 cm−1. The nonlinear index of a material is measured relative to that of a standard with a known index. Our measurements of 27 glasses are in good agreement with previous results, where available, and with the n2 values calculated empirically from linear index parameters. We also discuss the relationship between the observed nonlinear index and the structure and composition of the glasses.