Parametric wave mixing enhanced by velocity insensitive two-photon excitation in Rb vapour

TL;DR

This paper explores how cell orientation and velocity-insensitive two-photon excitation enhance parametric wave mixing in rubidium vapor, leading to increased efficiency and distinct mid-IR emissions.

Contribution

It demonstrates the significant impact of cell orientation and velocity-insensitive two-photon excitation on wave mixing efficiency and spectral characteristics in Rb vapor.

Findings

Cell orientation affects intensity and spectral features of generated fields.

Velocity-insensitive two-photon excitation enhances coherent light generation.

Distinct mid-IR fields can be produced simultaneously via different excitation pathways.

Abstract

We demonstrate how the orientation of the Rb cell can significantly affect the intensity and spectral characteristics of both the frequency up- and down-converted fields generated by nonlinear processes in Rb vapour. The efficiency of parametric wave mixing in Rb vapour excited to the 5D5/2 level by two-colour resonant laser light can be significantly increased by seeding the excitation region with coherent and directional radiation at 5.23 um that is resonant with the population inverted 5D5/2-6P3/2 transition. It has been shown that the process of velocity insensitive two-photon excitation is central to understanding the observed coherent blue and mid-IR light enhancements and that the velocity insensitive and velocity selective two-photon excitations could produce two co-existing but spectrally and spatially distinguishable mid-IR fields at 5.23 um.