Measurement of the nonlinear refractive index of air constituents at mid-infrared wavelengths

TL;DR

This study measures the nonlinear refractive index of atmospheric gases N₂, O₂, and Ar across visible to mid-infrared wavelengths, providing data crucial for modeling ultrashort pulse propagation in the atmosphere.

Contribution

It provides experimental measurements of the nonlinear refractive index coefficients of air constituents in the mid-infrared range, aligning with theoretical models.

Findings

Good agreement with theoretical $ ext{χ}^{(3)}$ models

Data covers atmospheric transparency windows

Results aid in simulating ultrashort mid-IR pulse propagation

Abstract

We measure the nonlinear refractive index coefficients in N$_2$, O$_2$ and Ar from visible through mid-infrared wavelengths (\lambda = 0.4 - 2.4 {\mu}m). The wavelengths investigated correspond to transparency windows in the atmosphere. Good agreement is found with theoretical models of $\chi^{(3)}$. Our results are essential for accurately simulating the propagation of ultrashort mid-IR pulses in the atmosphere.