Growth of spontaneous periodic surface structures on solids during laser illumination

TLDR

Laser‑induced ripples commonly form on metals, semiconductors, and dielectrics after intense pulse illumination. The study aims to develop a theory predicting ripple spacing, polarization, and growth. The model posits that surface‑disturbance Fourier components scatter light along the surface, and the resulting interference with the incident beam creates fringes that reinforce the disturbance. Sinusoidal surface corrugations on metals or molten surfaces provide strong positive feedback for ripple growth, while temperature, electron‑hole density, or dielectric constant gratings are poorly correlated with observations.

Abstract

Spontaneous periodic surface structures, or ripples, are frequently observed after illumination of metals, semiconductors, and dielectrics by intense laser pulses. We develop a theory which predicts the observed spacing, polarization, and growth properties of these ripples. In this model, one or several Fourier components of a random surface disturbance scatter light from the incident beam very nearly along the surface. The interference of this diffracted optical wave with the incident beam then gives rise to optical interference fringes which can reinforce the initial disturbance. Sinusoidal corrugations on either metallic or molten surfaces seem to provide strong positive feedback for ripple growth, whereas sinusoidal gratings in temperature, electron-hole density, or dielectric constant seem much less well correlated with observations.