Electron dynamics of femtosecond laser induced plasma inside multilayer dielectric high reflectors studied using particle-in-cell (PIC) approach

The ultrahigh-intensity laser systems are crucial to various applications such as particle acceleration and research of extreme conditions. Therefore, a higher laser induced damage threshold (LIDT) of optical components is demanded. To study the mechanisms of the ultrafast laser-solid interaction, the modeling is important. Traditional modeling of ultrashort laser-solid interaction is based on Finite-Difference-Time-Domain (FDTD) that can only reveal the electromagnetic field distributions. However, Particle-in-Cell (PIC) simulation can reveal both the field distributions and the particle dynamics. We used and modified EPOCH with Keldysh photoionization and a model for a spatially varying permittivity to capture the thermalization of the electrons and the plasma generation in a multi-layer dielectric mirror irradiated by a few-cycle pulse and predict the LIDT. The modeling work can provide guidance on designing and manufacturing of the optical components.