TEMPERATURE AND EMISSION SPATIAL PROFILES OF LASER-INDUCED PLASMAS DURING ABLATION USING TIME-INTEGRATED EMISSION-SPECTROSCOPY

Emission spectra and excitation temperature spatial profiles, within l aser-induced plasmas from solid copper targets, are characterized as a function of laser power density with the use of time-integrated emiss ion spectroscopy. This research shows how the measured axial spatial e mission intensity of the expanding plasma can be influenced by the tim e integration. The excitation temperatures calculated from these integ rated emission-line intensities may not coincide with the actual tempe rature spatial profile. Transient plasma dynamics during time-integrat ed intensity measurements can influence both the excitation temperatur e and the atomic number density of the emitting species. As a demonstr ation of the influence of fluid dynamics on time-integrated emission m easurements, a shock-wave model was used as an example to show bow the spatial emission intensity profile of a laser-induced plasma can be a ffected by transient expansion. Even for time-resolved emission measur ements, the high velocity of a laser-induced plasma can influence spat ial intensity data close to the target surface. The ability to accurat ely measure spatial emission intensity and temperature behavior is sho wn to be related to the integration time vs. plasma expansion velocity .