Mechanism of nanograting formation on the surface of fused silica

Nanograting inscription with a tightly focused femtosecond beam on the surface of fused silica was studied. The width and spacing of grooves are shown to decrease with the increase of the number of overlapped shots in both stationary and scanning cases. We propose a model to explain this behavior, based on both the so-called nanoplasmonic model and the incubation effect. (C) 2012 Optical Society of America