SPATIAL AND TEMPORAL CHARACTERISTICS OF AN EXCIMER LASER-INDUCED LEADPLASMA EMISSION

A laser-induced plasma was generated from a lead target using an ArF e xcimer laser (lambda = 193 nm) and characterized by time-resolved and time-integrated spatially resolved spectrometry. The ambient atmospher e (gas composition and pressure) influenced the emission intensity for both atomic and ionic lines. The emission of laser-induced lead plasm a varied with time as well as the location in the plasma. Lead ion emi ssion decayed more rapidly than lead atomic line emission. High excita tion temperatures and nonlinear optical phenomena were observed in the laser-induced lead plasma. Gas breakdown and the subsequent shielding effect of the incident laser beam in different ambient gas compositio ns and pressures were discussed to explain the different efficiency of metal ion formation in the plasma. The experimental results show that spatial discrimination of the laser-induced plasma emission is desira ble for direct spectrochemical analysis.