Dynamic thermal response of aluminum films induced by femtosecond-pulsed lasers with temperature dependent optical properties

This paper reports two optical models of temperature dependent reflectivity, R, and absorption coefficient, α, during femtosecond laser interaction with aluminum. After a comparison with existing experimental data, the critical point model (CPM) was incorporated into a two-temperature model (TTM) to simulate laser energy deposition and thermal response in an aluminum film irradiated by femtosecond laser pulses. The dynamic change of optical properties R and α, distribution of laser heat density, electron and lattice temperature of an aluminum film were investigated. Compared with constant reflectivities and absorption coefficients, dynamic reflectivities and absorption coefficients are recommended to be employed in modeling ultrafast laser heating.