Optimization of experimental parameters about laser induced breakdown and measurement of soil elements

The experimental parameters for observing the characteristic of laser induced breakdown (LIB) plasma are optimized in the atmospheric environment. It shows that when the laser pulse energy is 21 mJ, the focal length of lens is 15 cm and the sample is 2 mm in front of the lens focus, the spectral intensity and the ratio of signal to noise (SBR) of LIB plasma are highest. It is helpful to improve the detection accuracy of the technique of laser induced breakdown spectroscopy (LIBS). The LIB spectra of a special soil samples are observed with the optimized parameters. The elements Fe, Mn, Ca, W, Co, Ti, Si, Cr and V contained in the soil sample are determined based on the spectral peaks. The electron temperature in plasma and the quantities of Mn, Ca in the soil are obtained further.