Vortex-controlled morphology conversion of microstructures on silicon induced by femtosecond vector vortex beams

Abstract

We demonstrate the morphology conversion of surface microstructures on silicon induced by femtosecond vector vortex beams. By tuning the topological charge of the vortex phase carried by the vector beam, we achieve the transition of ablation crater between subwavelength ripples and hole, and the switching of ripple orientation. It is shown that the vortex phases give rise to the converting of the two polarization components of the focused vector beams, and produce dramatically different polarization and intensity distributions in the focal fields. Such vortex-dependent focal fields of femtosecond vector beams are experimentally generated to realize the morphology conversion of surface microstructures on silicon. Our results not only enable the realization of manipulating the laser-induced morphology but also support the visualized mapping of the polarization state of the focused vector beams.