Development and characterization of a 2.2 W narrow-linewidth 318.6 nm ultraviolet laser

TL;DR

This paper reports the development of a high-power, narrow-linewidth UV laser at 318.6 nm with stable output and tunability, suitable for Rydberg excitation in cesium atoms, using fiber lasers and nonlinear frequency conversion.

Contribution

It introduces a novel high-power UV laser system with over 2 W power, narrow linewidth, and broad tunability, based on efficient nonlinear conversion of commercial fiber lasers.

Findings

Achieved 2.26 W UV power with 57.3% doubling efficiency

Maintained power fluctuation below 0.87% over 30 minutes

Provided a tunable range of over 6 GHz for the UV laser

Abstract

We demonstrate a high-power narrow-linewidth ultraviolet (UV) laser system at 318.6 nm for direct 6S1/2-nP (n = 70 to 100) Rydberg excitation of cesium atoms. Based on commercial fiber lasers and efficient nonlinear frequency conversion technology, 2.26 W of tunable UV laser power is obtained from cavity-enhanced second harmonic generation following sum-frequency generation of two infrared lasers at 1560.5 nm and 1076.9 nm to 637.2 nm. The maximum doubling efficiency is 57.3%. The typical UV laser power root-mean-square fluctuation is less than 0.87% over 30 minutes, and the continuously tunable range of the UV laser frequency is more than 6 GHz. Its beam quality factors M2 X and M2 Y are 1.16 and 1.48, respectively. This high-performance UV laser has significant potential use in quantum optics and cold atom physics.