Utilizing Vortex pulse and suitable focus distance to improve the stability of laser-induced breakdown spectral (LIBS)

Abstract In order to study the signal stability of reheated double pulse laser-induced breakdown spectroscopy (LIBS). Utilizing single Gaussian and Vortex pulse, the distance between the lens and sample is changed to exam the focus position effect by measuring the plasma emission spectrum. The maximum signal intensity is achieved when the focal point is behind the target. In the double Gaussian and Vortex-Gaussian LIBS schemes, the variation of spectral intensity with the inter-pulse delay time are also investigated. The change of spectral intensity with the inter-pulse delay time has a great correlation with the energy of Vortex pulse and presents a completely different trend with a low, medium and high laser pulse energy. The spectral intensity of plasma emission is closely related to the plasma temperature. Meanwhile, the Vortex-Gaussian scheme can significantly improve the spectral stability at low laser energy flux. These results show that the combination of Vortex beam and Gaussian beam can greatly enhance the spectral intensity and detection stability, presenting a strong application prospect in nondestructive detection.