Ultrafast Laser Heating on Metal Films: Effects of Microvoids

摘要

The effect of internal voids in microfilms on the change of the surface reflectivity is analyzed. The dual-phase-lag model is employed to describe the interweaving behaviors of thermalization and relaxation during the short time transient. The normalized temperature change in the two-dimensional films containing a microvoid is obtained by an explicit algorithm of finite differencing, aiming at retrieval of the Crank-Nicholson criterion as a special case. The presence of micro voids can significantly reduce the normalized surface reflectivity change, sometimes by one order of magnitude, which has been observed experimentally.