The thermal behavior of thin metal films in the hyperbolic two-step model

A new approach, based on the physical decoupling of the hyperbolic two-step model, is introduced to describe the thermal behavior of a thin metal film exposed to picoseconds thermal pulses. The approach is based on the assumption that the metal film thermal behavior occurs in two separate stages. In the first stage, electron gas transmits its energy to the solid lattice through electron–phonon coupling and other mechanisms of energy transport are negligible. In the second stage, electron gas and solid lattice are in thermal equilibrium, the energy transfer through electron–phonon coupling is negligible, and thermal diffusion dominates. The proposed approach eliminates the coupling between the energy equations and the reduced differential equations are easier to handle. The proposed approach applies to metal films whenever the dimensionless parameter GL2/Ke is much larger than one.