Abstract

Transient thermal waves generated by the absorption of a very short laser pulse at the interface between two media are studied theoretically. The analysis employs Green functions for an instantaneous line heat source derived by the Cagniard–de Hoop method. These Green functions demonstrate that the properties of the temperature fields are determined by two dimensionless parameters, namely, the square root of the ratio of the thermal diffusivities and the ratio of the thermal conductivities of the two media. It is shown how these two parameters can be extracted using characteristic features of the temperature fields in both media.

© 2003 SPIE