Self-scattering effects in femtosecond laser nanoablation

We experimentally investigate the self-reflectivity of intense strongly focused femtosecond laser pulses used for single-shot femtosecond laser ablation of silicon-on-insulator (SOI). We model the self-reflectivity using 2D finite-difference time-domain simulations of a single femtosecond laser pulse interacting with a submicrometer-sized time- and space-dependent plasma induced by the incident pulse itself and find excellent agreement with our experimental results. The simulation shows that the laser-induced plasma scatters the incident pulse into the guided modes of the device layer of the SOI.