Laser short-pulse heating: three-dimensional consideration

Non-equilibrium energy transport takes place in solids once the laser pulse duration reduces to picoseconds or less. It is this energy transfer mechan ism that defines the laser interaction process and therefore the rate at wh ich the material is heated through the collisional process. In the present study, laser short-pulse heating of a gold surface is considered. An electr on kinetic theory approach is introduced to model the energy transport proc ess in three dimensions. The governing equation of energy transport is solv ed numerically, and the electron and lattice site temperatures are predicte d. In order to validate the electron kinetic theory predictions, a two-equa tion model is employed to compute the temperature field in the substrate ma terial. It is found that energy transport due to the diffusional process is unlikely during the heating period considered at present. The predictions of electron kinetic theory agree well with the results obtained from the tw o-equation model.