The Research Of Laser Induced Cu Plasma Emission Spectra In Air

Laser-ablation has been widely used as a available and convenient method to produce metal plasma in various applications and researches, but there are many unsolved problems because the complex process of reaction between laser and plasma. In recent ten years, by the laser-ablation technique is used in thin film preparation, nanomateriel formation and other new semiconductor material researches, a more detail mechanism of plasma formation, expansion and chemical reaction is needed urgently. Copper is an important noble metal in industrial application, so the study of its plasma properties and reactions with molecules and clusters has a significant meanings in theory and practice. In this thesis, the study results of the basic characteristics of laser-ablation Cu plasma are given, Following are the details, (a) The research of laser induced Cu plasma emission spectra in airUsing Nd:YAG laser (with a wavelength of 1064nm and a pulse width of 10ns) ablate copper target in air to observe the emission spectra of plasma. The space-resolved spectra are measured in the wavelength of 440nm to 540nm at the different laser energy. Under the model of local thermodynamic equilibrium, the electronic temperature of Cu plasma are deduced to be in the 104 scale by the relative line intensities. Finally, space characteristics of electron temperature are obtained near the target, the strength and FWHM (the full width half maximum) of N(II)500.52nm spectral line are analysed. (b)Spatial characterization of laser induced Cu plasma in air with different laser focusing distancesThe plasma spectra induced by pulsed laser ablation of copper target are measured. By adjusting the distance of the len-sample, the spectrum of air spark plasma, Cu plasma and the reciprocity of both plasmas are analysed. From the result, it has been shown that the focusing of the laser beam has an important infunence to analyse the properties of the sample.