Traditionally UV radiation produced by spark or corona sources has been used to generate preionization electrons in high-pressure self-sustained gas-discharge lasers. Although this technique is simple and effective, it does not permit control of the density, spatial distribution, duration, and timing of preionization to be easily achieved. For this reason, few experimental investigations into the influence of preionization conditions on discharge development have been undertaken, and the preionization kinetics of high-pressure gas lasers have been poorly understood. Recently short-duration high- intensity pulses of x rays1 (λ ~ 0.2 Å; pulse duration, ~40 nsec) and coherent UV photons from a small excimer laser2 (λ = 248 nm; pulse duration, ~15 nsec) have been successfully used to preionize XeCl lasers. As well as being potentially useful preionization techniques in their own right (for example, in the preionization of large discharge volumes) these short-pulse sources can provide considerable insight into the preionization kinetics.
© 1983 Optical Society of AmericaPDF Article