Polarization and angular effects of femtosecond laser-induced nanostructure-covered large scale waves on metals

摘要

In this paper, we find that nanostructure-covered large scale waves (NC-LSWs) can be produced on metals using both s- and p-polarized femtosecond laser pulses. We show that the period of NC-LSWs can be controlled by laser fluence, the number of irradiating pulses, and the incident beam angle. By modeling angular dependence of NC-LSW period induced by s-polarized light, we reveal that inhomogeneous energy deposition plays an important role in the formation of NC-LSWs. This allows us to establish a three-step model for NC-LSW formation, the formation of laser-induced surface unevenness, inhomogeneous energy deposition due to the interference of the incident light with the scattered light, and nonuniform energy deposition due to shielding by LSWs.