XECL EXCIMER LASER-INDUCED SHOCK-WAVE PLASMA AND ITS APPLICATION TO EMISSION SPECTROCHEMICAL ANALYSIS

A XeCl excimer laser (20 ns, 15-70 mJ) has been focused on a Zn plate in surrounding gas at low pressures (100-1500 Pa). The characteristics of the resultant plasma are examined with the use of a unique time-resolved spectroscopic method. A density jump in the distribution of Zn atoms is clearly observed, which indicates the generation of a shock wave. Furthermore, it is proved that the relationships among the displacement length of the front of the emission of the Zn neutral emission line, the pressure of the ambient gas, and the energy of the laser pulse are in good agreement with the theoretical result for a blast wave explosion. An application is also presented to show that the plasma induced by a blast wave is excellent as a light source for emission spectrochemical analysis because of its very low background emission intensity.