Self-organized Surface Patterns Originating from Laser-Induced Instability

Abstract

Self-organized surface pattern formationPattern formation upon femtosecond laser ablationFemtosecond laser ablation is considered in framework of an adopted surface erosion model, based on the description for spontaneous pattern formation on ion bombarded surfaces. We exploit the similarity to ion-beam sputtering and extend a corresponding model for laser ablation by including laser polarization. We find that an asymmetry in deposition and dissipation of incident laser energy, related to the laser polarization, results in a corresponding dependence of coefficients in a nonlinear equation of the Kuramoto-Sivashinsky type. We present the surface morphologies obtained by this model for different polarization of the laser beam and discuss a time evolution of the nanopattern. A comparison of numerical results with experimental data shows an excellent qualitative agreement. Our results support the non-linear self-organization mechanismSelf-organization mechanism of pattern formation on the surface of solids.