Examination of potassium diode pumped alkali laser using He, Ar, CH₄ and C₂H₆ as buffer gas

We examined the performance of a potassium diode pumped alkali laser (K DPAL) using He, Ar, CH₄, C₂H₆ and a mixture of He and CH₄ as a buffer gas to provide spin-orbit mixing of the 4P_3/2 and 4P_1/2 states of Potassium atoms. We found that pure helium cannot be used as an efficient buffer gas for continuous wave lasing without using a flowing system with a considerable flow speed of about 100 m/s. In contrast, using a small amount of methane (10-20 Torr) mixed with helium, continuous wave lasing can be achieved using very moderate flow speeds of about 1 m/s.