Thermal response of double-layered metal films after ultrashort pulsed laser irradiation: The role of nonthermal electron dynamics

The thermal response of a Cu-Ti double-layered film is investigated after laser irradiation with ultrashort pulses (pulse duration tau(p) = 50 fs, 800 nm laser wavelength) in submelting conditions by including the influence of nonthermal electrons. A revised two-temperature model is employed to account for the contribution of nonthermal electron distribution while the variation of the optical properties of the material during the laser beam irradiation is also incorporated into the model. Theoretical results can provide significant insight into the physical mechanism that characterize electron dynamics and can facilitate production of controllable ultra-high strength Cu-Ti alloys with promising applications. (C) 2014 AIP Publishing LLC.