Transit effects for non-linear index measurement in hot atomic vapors

TL;DR

This paper introduces tools for measuring the non-linear index in hot atomic vapors, emphasizing the importance of transit effects in accurate characterization, which is crucial for advancing non-linear and quantum optics applications.

Contribution

The work provides novel measurement techniques and numerical estimation methods for the non-linear index, highlighting transit effects in hot atomic vapors.

Findings

Transit effects significantly influence non-linear index measurements.

The proposed tools enable accurate characterization of non-linear susceptibility.

Transient and steady-state responses are effectively analyzed.

Abstract

Hot atomic vapors are widely used in non-linear and quantum optics due to their large Kerr non-linearity. While the linear refractive index and the transmission are precisely measured and well modeled theoretically, similar characterization remains partial for the $\chi^{(3)}$ non-linear part of the susceptibility. In this work, we present a set of tools to measure and estimate numerically the non-linear index of hot atomic vapors both in the steady state and during the transient response of the medium. We apply these techniques for the characterization of a hot vapor of rubidium and we evidence the critical role played by transit effects, due to finite beam sizes, in the measurement of the non-linear index.