Short-time thermoelastic contributions to picosecond-time scale reflectivity measurements of metals

The thermoelastic transients observed in aluminum during the first few picoseconds after absorption of a subpicosecond duration laser pulse are described through numerical simulations using a nonlinear, two-temperature parabolic model of thermal stresses. Comparisons between these simulations and experimental measurements obtained from a single-crystal aluminum sample and polycrystalline aluminum films on silicon illustrate that the thermal and elastic transients must both be considered at all times in order for the physical properties that are interpreted from the experimental measurements to be consistent with those obtained from other measurements made at various time scales. (C) 2002 American Institute of Physics.