Ripple structures associated with ordered surface defects in dielectrics

Laser-induced ripple structures on material surfaces have been observed by a number of workers for various materials including metals, semiconductors, and dielectrics. A model has been proposed [1] which correctly accounts for the spacing and polarization dependence of the ripples, and the association of the ripples with material defects. In this letter, experimental results which unambiguously show the association of these features with defects are presented. Quantitative measurements of laser-induced damage thresholds show a reduction of damage thresholds for surfaces with controlled linear defects aligned orthogonal to the incident laser field (as predicted in [1]).