ABSTRACT
The authors present a one-dimensional calculation model of H3(+), and the time-dependent wavefunction was obtained by the symmetric split-operator method. The authors investigated the high-order harmonic generation (HHG) properties of H3(+) model exposed to 800 nm-wavelength ultrashort laser pulse. The effect of electron interaction on the HHG spectra is less profound than at the cut-off frequency. We also calculated the HHG spectra for different internuclear separation values close to realistic one. Most of the calculated cutoff frequencies are beyond the three-step model's prediction, and a preliminary scenario is suggested.
ABSTRACT
Single-shot laser induced breakdown spectroscopy (single-shot LIBS) has become one of the most important branches of material detection. The present article mainly focuses on analysis of the emission spectra of lead by quantitative methods. In the experiment, both qualitative and quantitative analysis are made to detect the content of lead in different material using single-shot LIBS with Q-switched Nd:YAG lasers whose pulse width is 10ns. In quantitative analysis, detections of the emission lines of pure lead with different pulse energies: 107, 139.2 and 171.5 mJ and different wavelengths: 1064, 532 and 1064/532 nm are made. Spectra under three conditions (1: same wavelengths and different pulse energies for single pulse lasers; 2: same pulse energy and different wavelength for single pulse lasers and 3: same wavelengths and different pulse energies for double pulse lasers) are acquired and compared.
ABSTRACT
In the present paper, the lead concentrations of samples including glass, soldering tin and so on were determined by LIBS based on a Nd : YAG Q-switched pulse laser with wavelength 1 064 nm as an exciting source and CCD in common spectrograph as the detector. The pulse energy on the surface of samples is about 95 mJ and the pulse width is 12 ns. By the detection of different samples, the detection limit of lead in samples was found to be 0.007 4% and the maximum relative standard deviation of quantitative analysis was about 4.0% based on the LIBS system of the instruments all made in China. The quantitative analysis can be done in two or three minutes and will spend one minute finishing the process by software in the future. The results suggest that the accuracy of determination of lead meets the challenge of quantitative analysis and the CCD can displace the very expensive ICCD as detector. The feasibility and low cost of the method, which uses common spectrometer and CCD to realize the LIBS detection, is proved by the result and our investigation will be beneficial to the LIBS application.