An Assessment of e-Beam Controlled Discharge Pumping in KrF and XeCl Lasers

Abstract

The characteristics of KrF and XeCl laser media pumped by e-beam controlled discharge have been studied. A glow discharge easily turns into an arc in the KrF laser medium, in which Ar is used as a buffer gas, and a maximum enhancement ratio of 3 only was obtained. A glow discharge is much more stable in the XeCl laser medium, in which Ne buffer gas is used, and a maximum enhancement ratio of 6 was obtained by maintaining stable glow discharge for as long as the electron beam of 150 ns FWHM duration was injected into the medium. The amplification characteristics of the XeCl medium were studied, and a small-signal gain of 1.5%/cm, an absorption coefficient of 0.2%/cm, a saturation intensity of 1.2 MW/cm2 and an internal conversion efficiency of ∼4% were obtained at a pumping density of 0.2 MW/cm3. Thus, e-beam controlled discharge has been found to be useful in the low-pumping-density and long-pulse operation of XeCl lasers.