Application of KTP crystal to change plasma temperature in emission analysis problem

Nonlinear crystals have found wide application in laser technology for solving such problems as converting laser radiation into the second harmonic or for electro-optical modulation. Along with the second harmonic generation, the KTP crystal can be used to increase the kinetic energy of an electron in plasma by controlling the type of laser radiation polarization. This phenomenon has great importance for performing elemental analysis of a substance by femtosecond laser-induced breakdown spectroscopy method (Fs-LIBS). The report presents the results of study the effect of laser radiation polarization on the plasma temperature when implementing the Fs-LIBS method depending on the crystal rotation angle and effective second harmonic generation. It is shown that the increasing of the phase difference between ordinary and extraordinary radiation, the plasma temperature increases, which leads to a non-selective increase in the intensity of the emission lines of the substance. The obtained results have great practical importance in the problem of increasing the sensitivity of the Fs-LIBS method.