Femtosecond laser induced surface structuring on silicon by diffraction-assisted micropatterning

Abstract

Femtosecond laser micropatterning of silicon with nanometric surface modulation is demonstrated by irradiating through a diffracting pinhole. The irradiation results obtained at fluences above the melting threshold are characterized by optical and scanning electron microscopy and reveal a good agreement with Fresnel diffraction theory. LIPSS have been generated in the micropatterning surface. We found Ripples spacing were found of 550-680 nm. Based on the Sipe and Drude model, the theoretical period of LIPSS is closer to experimental measurements. Due to the diffraction, the LIPPS having a different period appear in a diffraction micropatterning.