Resonant holographic interferometry measurements of laser ablated atom absolute-line-density profiles in vacuum, gases, and plasmas

Summary form only given, as follows. Two-dimensional, species-resolved, double-pulsed holographic interferometry has been used to investigate the hydrodynamics of KrF laser ablation plumes in vacuum, gases, and RF plasmas. To produce the laser ablation plume, a KrF excimer laser (40 ns, 248 nm, /spl les/ 0.8 J) was focused onto a solid aluminum target at a fluence of 1.9 - 4.7 J/cm/sup 2/. The interferograms were made using an XeCl-excimer-laser-pumped dye laser (20 ns, /spl ap/ 5 mJ) tuned at or near (/spl plusmn/ 0.100 nm) the 394.401 nm aluminum neutral transition from ground state. Calculations have been performed to obtain aluminum-neutral absolute-line-density profiles from the resonant fringe shift data, assuming an average kinetic plume temperature of /spl ap/ 0.3 eV and a dye laser bandwidth of /spl ap/0.0031 nm. Peak aluminum neutral line-densities of up to 9 /spl times/ 10/sup 10/ cm/sup -2/ have been measured for plumes in backgrounds of 1 Torr and 35 Torr argon and 1 Torr argon RF-plasma, and in vacuum.