Anisotropic reversing motion in laser-induced periodic surface structures

Abstract

Observation of the evolution process of laser-induced periodic surface structure (LIPSS) will provide clues to its formation mechanism. 
We constructed a pulse-by-pulse image capture setup using oil-immersion optical microscopy with which we observed the evolution process on a coverslip of borosilicate glass, finding three LIPSS patterns: stripe patterns parallel and perpendicular to the electric field of the laser pulse, and a dot pattern. 
Furthermore, ``reversing'' motion was observed, that is, bright and dark interchange from pulse to pulse. 
The reversing motion had remarkable anisotropy, moving only perpendicular to the electric field of the laser pulse.