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.