LASER-INDUCED TEMPERATURE DISTRIBUTION IN SUBSTRATES WITH PERIODIC MULTILAYER STRUCTURES

A general model and analytical results have been derived to obtain laser-induced temperature rise in substrates with periodic multilayer structures. The substrate can be equivalent to a homogeneous substrate with anisotropic thermal conductivity, if the dimension of the periodic structure is much smaller than the laser spot size. The laser-induced temperature rise can be then obtained by solving the three-dimensional heat equation with the different thermal conductivities in directions parallel and perpendicular to the layer structure. This model has been applied to calculate the laser-induced temperature rise in Si and Mn-Zn ferrite composite materials. A different temperature rise can be obtained when a laser beam irradiates the substrate surface, which is oriented in parallel or perpendicular to the layer structure.