Femtosecond laser-induced nanometer-scale rods on silicon surface

Abstract

We report that silicon surface develops nanometer-scale rods when irradiated with two steps of six femtosecond laser pulses aggregately of 800 nm, 35fs duration in air. The evolution of the rods also has been studied. The result indicates that the rods disappear and only ripples with direction being perpendicular to the polarization of the laser in the second step remain, when the number of the laser pulses increase from three to five. The formation of the nano-scale rods involes several processes which include interference of refracted light and scattered light, surface capillary exceted, re-solidation of silicon surface, roughness-enhenced optical absorption. Copyright © Taylor & Francis Group, LLC.