Due to the characteristics of its working principle, it has two main types: 1. "Thermal processing" laser beam with high energy density irradiates the surface of the processed material, and the surface of the material absorbs the laser energy and produces a thermal excitation process in the irradiated area, so that the surface temperature of the material rises, resulting in metamorphosis, melting, ablation, evaporation and other phenomena. 2. "Cold working" photons with high load energy can break the chemical bonds in the material or the surrounding medium, so that the material is damaged by non-thermal process, because of its particularity, it does not produce heating or thermal deformation on the inner layer and nearby areas of the processed surface. In this article