Modeling and Measurements of Metastable Argon Atoms in a Radio-Frequency Capacitive Discharge

The metastable rare gas atoms are used as lasing species for optically-pumped rare gas laser (OPRGL), which are mainly produced by electrical discharge. Radio-frequency (RF) capacitive discharge is a promising technique for the continued production of the large volume needed for OPRGL systems. In this work, we examined the feasibility of using a RF discharge to produce a continuous gain medium with a gain volume of 4 cm
³
. Metastable argon atoms were measured using tunable Ti: sapphire laser absorption spectroscopy. Simulations of an $\alpha-$ mode RF discharge are performed for varying mixtures of argon and helium using a one-dimensional model. The model is validated qualitatively and quantitatively by measurement in many aspects. The measured and simulated results indicated that the metastable densities decrease with the pressure and reach a peak as the Ar-fraction increases. The model predicted a 35 times increase in peak power with respect to the continuous wave power by use of the cavity dumping technique.