The Research Of Laser Induced Cu,Al Plasma Emission Spectra

In view of laser-ablation has been widely used as various research domains, the interaction mechanism of a laser-pulsed with solid targets arose the interesting of more and more relevant scholars, Including laser plasma formation, ablation of the sample surface, vaporization and excitation of different species. The processes are known to depend on the laser pulse characteristics (such as energy, pulse duration ,wavelength, interacting time and so on), the physical and chemical characteristics of samples, environmental condition as well as buffer gas. The processes are rather complex. Many scholars have had plentiful research on the ablating rate of target, average kinetic energy of the production and ray radiation law of the production by the way of changing the interacting condition, including laser wavelength, pulse duration , intensity, target material and the pressure of environment gas and other factors. The comprehension is still not very clarity at present. The energy state of ablating particle, time-space action and their relevant mechanism need to be revealed and perfected gradually. In this thesis, the basic character of Cu and Al plasma are studied by the emission spectrum which is produced in the condition of laser ablation and additional electric field. Following are the details.(1) The research of laser induced Cu plasma emission spectrum.Laser induced Cu plasma in Ar buffer gas are studied. The space-resolved spectra are measured in the wavelength of 440nm～540nm at the 350mJ/pulse of laser energy. Under the model of local thermodynamic equilibrium, the electronic temperatures of Cu plasma are deduced to be in the 10~4 scale by the relative line intensities. The dependence of emission spectra line intensity and electronic temperature and FWHM (the full width half maximum) on the space and pressure of buffer gas are studied. The results show that intensity of the Cu spectral lines decrease but the intensity of the Ar ion spectral lines and background increase comparing the pressure of 100kPa with 50kPa in Ar ambient gas. At the same time, the broadening increases with increasing the pressure of buffer gas.(2) An experimental investigation on the properties of Laser - induced Al plasma under additional electric fieldThe plasma is produced by ablating Al target with Q-switch Nd:YAG Laser ( wavelength 1.06μm, pulse width 10ns). Al emission spectrum are observed in the low air pressure and the direct electricity field. The influence of the spectral line intensity in various laser power density and direct electricity field is studied. The electron temperature of plasma in various laser power density and FWHM of the spectral line in direct electricity field are measured. The results show that the spectral line intensity of Al atom is increased prominently in direct electricity field. The FWHM of spectral line of Al atom in various additional voltage of direct electricity field is linear.