Spectral characteristics of vacuum ultraviolet preionization sources for CO2 lasers

Results are presented of a comparative study of the radiation spectra of spark and surface discharges in the 114–200 nm range. It is shown that both complete and incomplete surface discharges are a more efficient source of ultraviolet radiation for preionization of the active volume of CO₂ lasers than spark discharges. This is attributed to the possibility of concentrating the radiation energy in the required spectral range and of locating the discharge plasma in the optimal position with respect to the laser active volume. An analysis of the time behavior of the radiation intensity of the most characteristic spectral lines showed that the changes in the spectrum of an incomplete surface discharge with polarity reversal of the supply pulse were associated with the surface-discharge-formation mechanism.