Controlling laser-induced self-organized patterns via engineered defects

Abstract

Nanoscale periodic surface structures are of paramount importance in material science [1]. The recently demonstrated Nonlinear Laser Lithography (NLL) technique allows creating nanostructure arrays over indefinitely large surfaces with remarkable periodicity, not attainable by conventional laser induced periodic surface structure (LIPSS) methods [2]. Using NLL with linearly polarized femtosecond pulses, nanolines parallel to polarization emerge from initial surface roughness, and propagate on the surface as the laser beam is scanned. Here, we demonstrate that the final surface patterns depend not only on the polarization, but also on the surface morphology, which is controllable by introducing artificial defects. We use line defects as a control parameter to select a surface tiling from a set of available ones.