Effect of sample temperature on spectroscopic investigation of laser-induced aluminum and copper plasma

Abstract

In this work, the influence of samples temperature and laser energy on the optical emission spectra and plasma parameters of laser-induced breakdown spectroscopy for aluminum and copper metallic target is investigated. The samples are uniformly cooled down to -70 °C and heated up to 200 °C by an external liquid nitrogen and ceramic heater, respectively. The plasma formed is generated by ablating the surface targets using Nd:YAG laser with laser energies of 100 mJ, 200 mJ and 300 mJ. The emission spectra at ambient atmospheric pressure are recorded using HR4000 spectrometer. From these spectra, plasma temperatures and electron densities are determined by using Boltzmann plot and Stark broadening methods, respectively. A significant increase in the peak intensity of spectral lines is observed with increase in the laser energy as well as sample temperature for both elements. Both of these parameters have shown a clear influence on dynamics of laser-induced plasma for each species. In brief, both laser energy and sample temperature affect the emission intensity, temperature and density of the laser-induced plasma generated from aluminum and copper samples.