Collimated blue light generated by four-wave mixing in Rb vapour

TL;DR

This paper explores how four-wave mixing in rubidium vapor can efficiently generate collimated blue light through phase matching and velocity-selective excitation, with potential applications in ultraviolet light production.

Contribution

It demonstrates the role of four-wave mixing and phase matching in blue light generation in Rb vapor, highlighting velocity-selective excitation effects and discussing UV generation schemes.

Findings

Blue light is generated unidirectionally via four-wave mixing.

Phase matching conditions influence the direction and divergence of the blue light.

Doppler-free dependence observed due to velocity-selective excitation.

Abstract

We investigate frequency up-conversion of low power cw resonant radiation in Rb vapour as a function of various experimental parameters. We present evidence that the process of four wave mixing is responsible for unidirectional blue light generation and that the phase matching conditions along a light-induced waveguide determine the direction and divergence of the blue light. Velocity-selective excitation to the 5D level via step-wise and two-photon processes results in a Doppler-free dependence on the frequency detuning of the applied laser fields from the respective dipole-allowed transitions. Possible schemes for ultraviolet generation are discussed.