Modeling and experiments of self-reflectivity under femtosecond ablation conditions

Abstract

We present a numerical model that describes the propagation of a single femtosecond laser pulse in a medium of which the optical properties dynamically change within the duration of the pulse. We use a finite-difference timedomain method to solve the Maxwell's equations coupled to equations describing the changes in the material properties. We use the model to simulate the self-reflectivity of strongly focused femtosecond laser pulses on silicon and gold under laser ablation conditions. We compare the simulations to experimental results and find excellent agreement.