Efficient numerical approach for modeling coupled electron and nanosecond laser pulse propagation dynamics in dielectric materials.

Abstract

The interaction of intense laser pulses with matter leads to various applications since it enables the transformation of the state of matter owing to a localized energy deposition. The advances in this field rely in particular on the understanding of physical processes at play and the ability to evaluate such a laser energy deposition. The latter can be achieved by developing modeling and associated numerical codes, which have to be efficient to possibly address complex geometries and perform parametric studies. Within this framework, we have developed an efficient numerical tool to describe the interaction of a nanosecond laser pulse with a dielectric material. This description includes the laser propagation, which is consistently coupled to the laser-induced electron dynamics, from which the laser energy deposition is evaluated. The laser propagation and electron dynamics are described by solving the Helmholtz coupled to rate equations. A high-order finite volume scheme is introduced to solve the Helmholtz equation. The physical system dynamics is resolved through a modified Dormand-Prince algorithm, with an adaptive time step designed to efficiently account for the possible rapid change in the optical response of the target when the critical plasma density is reached. The ability of the proposed numerical scheme to efficiently tackle the laser-matter interaction problem is demonstrated. In particular, it is shown that the computational time of our approach can be shorter by one order of magnitude than the one obtained with the usual fourth-order Runge-Kutta method.