ArI/ArII laser induced fluorescence system for measurement of neutral and ion dynamics in a large scale helicon plasma

In order to investigate the role of both neutral and ion dynamics in large-scale helicon discharges, a laser induced fluorescence (LIF) system capable of measuring both ArI and ArII fluorescence using a single tunable laser is being developed. The system is based on a >250 mW solid state laser. For ArI measurements, the laser pumps the metastable (P-2(3/2)0)4s level to the (P-2(1/2)0)4p level using 696.7352 nm light, and fluorescence radiation from decay to the (P-2(1/2)0) 4s level at 772.6333 nm is observed. For ArII, currently in development, the metastable (P-3)3d F-4(7/2) level will be pumped to the (P-3)4p D-4(7/2)0 level using 688.8511 nm, and decay fluorescence to the (P-3)4s P-4(5/2) level at 434.9285 nm measured. Here all wavelengths are in a vacuum. Published by AIP Publishing.