Revealing kinetics of a diode-pumped metastable Ar laser in pulsed and CW lasing

We have experimentally investigated the kinetics of a diode-pumped metastable Ar laser by simultaneously monitoring the population evolution of 1s5 and 1s4 states during lasing. A comparison between the two cases with the pump laser on and off revealed the cause for the transition from pulsed to CW lasing. The depletion of 1s5 atoms was responsible for the pulsed lasing phenomenon, while increasing the duration and density of 1s5 atoms resulted in CW lasing. Furthermore, population accumulation of the 1s4 state was observed.