Neon excimer emission from pulsed high-pressure microhollow cathode discharge plasmas

Abstract

Microhollow cathode discharge (MHCD) plasmas in high-pressure Ne (up to and exceeding atmospheric pressure) are known to be efficient sources of Ne2∗ excimer radiation in the vacuum ultraviolet spectral region between 75 and 90nm. By operating the MHCD plasma in a pulsed direct current (dc) mode, we were able to increase the Ne2∗ excimer emission by up to 1 order of magnitude compared to the emission intensity obtained from the same MHCD plasma excited by a constant dc current. Time-resolved emission spectroscopic studies of the Ne2∗ excimer emission following pulsed dc excitation of an MHCD plasma in high-pressure Ne were carried out to elucidate the microscopic details of the excimer formation and destruction processes. Our studies provide direct evidence that quenching of the Ne2∗(3Σu) excimer molecules and other loss processes of the excimer molecules are important processes in high-pressure MHCD plasmas and represent, in fact, the dominant destruction channel of the Ne2∗(3Σu) excimer molecules in the MHCD plasma under a wide range of operating conditions.