THE MECHANISM OF THE CW SODIUM-VAPOR HYDROGEN LASER

Measurements have been carried out to gain information on the mechanis m of the cw 9 mum sodium-vapor/hydrogen laser [2]. Observations were c arried out on the laser excited with both cw and pulsed discharges and the low-power gain of various gas mixtures was measured using tunable diode lasers. The laser was found to oscillate with mixtures of sodiu m vapor with H-2, D2 and HD, but with no other gas. On substituting D2 for H-2 a more than three-fold increase in laser gain was observed. T he results showed that most of the processes used to explain lasing ac tion in other metal-vapor lasers were not applicable to the present ca se. It was concluded that the primary process which leads to the produ ction of the population inversion involves differential quenching of t he laser levels by molecular hydrogen, with the lower 3D level being q uenched more efficiently than the upper 4P level. Measurements carried out on the calcium/hydrogen laser [21] with D2 supported these conclu sions.