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

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 (²P⁰_3/2)4s level to the (²P⁰_1/2)4p level using 696.7352 nm light, and fluorescence radiation from decay to the (²P⁰_1/2)4s level at 772.6333 nm is observed. For ArII, currently in development, the metastable (³P)3d ⁴F_7/2 level will be pumped to the (³P)4p ⁴D⁰_7/2 level using 688.8511 nm, and decay fluorescence to the (³P)4s ⁴P_5/2 level at 434.9285 nm measured. Here all wavelengths are in a vacuum.