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 (2 P0 3/2 )4s level to the (2 P0 1/2 )4p level using 696.7352 nm light, and fluorescence radiation from decay to the (2 P0 1/2 )4s level at 772.6333 nm is observed. For ArII, currently in development, the metastable (3 P)3d4 F7/2 level will be pumped to the (3 P)4p4 D0 7/2 level using 688.8511 nm, and decay fluorescence to the (3 P)4s4 P5/2 level at 434.9285 nm measured. Here all wavelengths are in a vacuum.