Fig. 1. Laser experimental setup.

Fig. 2. (a) Cavity stability parameter versus thermal focal length of the laser gain medium; (b) beam sizes at different positions of the laser cavity.

Fig. 3. Output power versus absorbed power of the 640 nm laser; inset: (top-left) laser spectrum and (bottom-right) optical-optical efficiencies.

Fig. 4. Output power versus absorbed power of the 320 nm laser; inset: (top-left) output power stability and beam spot on a UV sensor card; (bottom-right) laser spectrum of the 320 laser.