Laser induced impedance changes in a neon hollow cathode discharge. A mechanistic study

Abstract

Irradiation of a neon‐supported, uranium hollow cathode discharge at wavelengths between 572 and 672 nm corresponding to optical transitions in neon or uranium causes significant changes in the impedance of the discharge. The behavior of these transitions can be separated into two general classes. (I) For transitions originating in the 1s levels of neon the impedance change is either negative or positive, depending upon the particular state, and the magnitude is proportional to the probability of depletion of these levels by optical pumping. (II) For other neon and all uranium transitions these impedance changes are negative and are proportional to the probability for absorption of laser radiation. Spatial variation of the impedance changes demonstrate the importance of collisions of the metastables with the cathode wall in maintaining the discharge.