Thermal Response of Metals to Ultrashort-Pulse Laser Excitation

Both electron thermal conductivity and thermal exchange with the lattice can cool an electron distribution initially heated on a metallic surface with an ultrashort laser pulse. The interplay between the two processes allows the electron-lattice coupling parameter to be determined. We report measurements of optical damage to molybdenum and copper. Damage caused by pulses have a duration ${\tau }_L\lesssim 1$ nsec can be understood only with a two-temperature model of metals.