Lattice Boltzmann Modeling of Ultrafast Laser Heating on Metal Film

Lattice Boltzmann method based on Boltzmann transport equation is developed to simulate the nanoscale heat transport in metal film. The Boltzmann transport equation is applicable to describe both electron and phonon scattering processes: the absorption of photon energy by electrons and the subsequent heating of metal lattice (phonons) through electron-phonon collisions. We show that the Boltzmann transport equation can give rise to the well-known two-temperature model. To validate our numerical tool, ultrafast laser heating on metal film is analyzed by lattice Boltzmann method and finite difference method based on two-step model separately, and exactly the same results are obtained. The predicted transient reflectivity changes agree with picosecond laser heating experiments data also.