Surface Plasmon Polariton Triggered Generation of 1D-Low Spatial Frequency LIPSS on Fused Silica

Simon Schwarz,Stefan Rung,Ralf Hellmann,Cemal Esen

doi:10.3390/app8091624

Abstract

We report on the generation of low spatial frequency laser-induced periodic surface structures along straight lines on fused silica by spatially scanning the laser parallel to its polarization direction. The influence of the applied laser fluence and the scanning speed on the periodic surface structures is investigated. The parameter study shows that periodic structures appear in a limited parameter regime of combined fluence and scan speed with periodicities smaller than the laser wavelength. Most strikingly, we observe a perpendicular orientation of the self-assembled periodic structures to the electrical field of the laser, notably a previously unreported result for this dielectric material. This behavior is explained taking into account calculations of surface plasmon polaritons including a Drude model for free carrier excitation within silica by femtosecond laser irradiation.

Highlights

Over the last few decades, Laser-Induced Periodic Surface Structures (LIPSS) have gained increasing attention due to the common availability of ultrashort pulsed laser sources
LIPSS have been shown on all material classes such as conductors [1,2,14], semiconductors [5,11,12] and dielectrics [12,15,16]
These so-called one-Dimensional LSFL (1D-LSFL) reveal periodicities larger than the wavelength of the applied laser and an orientation parallel to the polarization of the laser under normal irradiation, and neither conform with the established Surface Plasmon Polaritons (SPP) theory. This supra-wavelength (Λ LSFL > λ) type of LIPSS has been reported in several publications for punctual laser irradiation of dielectrics [34,35,36] with their generation being attributed to hydrodynamic instabilities within a convection roll-driven formation [34]

Summary

Introduction

Over the last few decades, Laser-Induced Periodic Surface Structures (LIPSS) have gained increasing attention due to the common availability of ultrashort pulsed laser sources. E.g., fused silica, the authors recently have shown the transfer from punctual laser irradiation into the dynamic range, i.e., moving the laser spot over the sample [16] These so-called one-Dimensional LSFL (1D-LSFL) reveal periodicities larger than the wavelength of the applied laser and an orientation parallel to the polarization of the laser under normal irradiation, and neither conform with the established SPP theory. This supra-wavelength (Λ LSFL > λ) type of LIPSS has been reported in several publications for punctual laser irradiation of dielectrics [34,35,36] with their generation being attributed to hydrodynamic instabilities within a convection roll-driven formation [34]. The periodicity of the structures reveals values between 0.9 μm and 1.0 μm, i.e., being smaller than the laser wavelength

Experimental Section

Results and Discussion

Conclusions