Optical emission properties of pulsed surface discharges

An investigation has been undertaken into the influence of parameters such as the nature of the cover gas, the dielectric substrate, and the circuit parameters on the performance of surface discharges used as optical sources. The effects of the magnitude and duration of the driving voltage pulse on the radiated optical output from a pulsed surface discharge in an SF₆-Ar gas mixture over a sapphire substrate have been measured within six spectral bands. It has been shown that the parameters studied can significantly affect the spectral distribution of the output of optical energy within these bands. The results show that the efficiency of optical emission within the 200-300 nm spectral band increases as the driving pulse duration increases from 250 to 1100 ns. This is in contrast to that found within the other spectral bands. The efficiency of optical emission in the 200-300 nm band has also increased with increasing discharge current, in contrast to the decrease observed for wavelengths greater than 700 nm.