Continuous wave diode pumped flowing-gas Cesium laser

Abstract

We report on the results of ongoing work in our lab on flowing-gas Cs DPAL. Some of the results have been already reported [Yacoby et al, Opt. Express 26, 17814 (2018)] but we briefly describe them here again to give a full picture of the work. Experimental and theoretical study of continuous wave Cs DPAL with gas circulation (He and CH4), flow velocities of 1-4.5 m/s and pump powers of 30-65 W, is reported. For the theoretical part of the study we used a 3D computational fluid dynamics model, solving the gas dynamics and kinetics equations relevant to flowing-gas laser operation. Maximum CW output power of 24 W and slope efficiency of 48% were obtained. The experimental and theoretical dependence of the lasing power on the flow velocity are in good agreement. The gas temperature rise in the laser cell was measured. The lasing power was not affected by the flow velocity at this range of pump powers and flow velocities due to the fact that the gas temperature rise was only several degrees. It was estimated – using a “fitting” method – that the quenching cross-section of the excited levels of Cs to the ground state is ~ 0.05 Å2 .