Spectral characterization of laser-induced air plasma by pulsed CO2laser

摘要

The spectral characterization of laser-induced air plasma by a pulsed TEA CO_2laser with a GaAs lens is reported. Thedata were collected using an ICCD spectrograph. The spectra of laser-induced plasma in the range of 300-900 nm andtheir spatial and temporal behaviors were investigated. Emission spectra of the N II lines occurring between 490 and520nm were analyzed in detail. The intensity peaks during the laser pulse approximately 0.7 μs and the peak emissionspectra decay over the first 1.5 μs. The spectra of plasma at different position were measured in the directions bothperpendicular and parallel to the laser propagation respectively. And the spectra of laser-induced air plasma produced bydifferent focal length lens were compared. The affection of different focal length lens for the plasma was described. Theshapes of horizontal directions were smaller with the shorter focal length and the intensities of the plasma were higher. Inaddition, the temperature of plasma was evaluated from the emission intensities. The peak temperature was more than10000K.