%0 Journal Article
%T Two-temperature relaxation and melting after absorption of femtosecond laser pulse
%A N. A. Inogamov
%A V. V. Zhakhovskii
%A S. I. Ashitkov
%A V. A. Khokhlov
%A Yu. V. Petrov
%A P. S. Komarov
%A M. B. Agranat
%A S. I. Anisimov
%A K. Nishihara
%J Physics
%D 2008
%I arXiv
%R 10.1016/j.apsusc.2009.04.139
%X The theory and experiments concerned with the electron-ion thermal relaxation and melting of overheated crystal lattice constitute the subject of this paper. The physical model includes two-temperature equation of state, many-body interatomic potential, the electron-ion energy exchange, electron thermal conductivity, and optical properties of solid, liquid, and two phase solid-liquid mixture. Two-temperature hydrodynamics and molecular dynamics codes are used. An experimental setup with pump-probe technique is used to follow evolution of an irradiated target with a short time step 100 fs between the probe femtosecond laser pulses. Accuracy of measurements of reflection coefficient and phase of reflected probe light are ~1% and $\sim 1\un{nm}$, respectively. It is found that, {\it firstly}, the electron-electron collisions make a minor contribution to a light absorbtion in solid Al at moderate intensities; {\it secondly}, the phase shift of a reflected probe results from heating of ion subsystem and kinetics of melting of Al crystal during $0<t<4\un{ps},$ where $t$ is time delay between the pump and probe pulses measured from the maximum of the pump; {\it thirdly} the optical response of Au to a pump shows a marked contrast to that of Al on account of excitation of \textit{d}-electrons
%U http://arxiv.org/abs/0812.2965v1