Kinetic study of a cw optically pumped laser with metastable rare gas atoms produced in an electric discharge

Abstract

An analytical model of a cw diode pumped laser that uses metastable rare gas atoms as the lasing species is developed, providing a method for quick assessment of a rare gas laser performance. Ar mixtures with He are analysed as examples of active media. Ar metastables are supposed to be produced in a glow discharge. Laser efficiency, gain and output power of this novel system are assessed as functions of Ar content, pressure, pump intensity and the system size along the direction of pumping radiation. Efficiency of metastables' excitation in a glow discharge is estimated solving Boltzmann equation. It was found that for efficient operation at 300 K optimal Ar content is of the order of 1% and the pressure is near atmospheric. Output power and specific discharge power increase with pump intensity essentially linearly, starting from 300 W cm−2. With pump intensity of 840 W cm−2 optical and total efficiency reach ∼60%, specific output power—500 W cm−3. At the same time, the discharge power density required to sustain sufficient metastables' number density amounts to 18 W cm−3 only.