In this paper the transient coupled conductive-radiative field, due to a la
ser heat source impinging on a thin film deposited on a substrate, has been
solved in the hypothesis of one dimensionality of the optical field and of
two dimensionality of the thermal field. Results have been obtained with t
he matrix method for the optical field and the finite volume method for the
thermal field. The results show that when the investigation is localized t
o the center of the spot, the one-dimensional model describes the thermal f
ield quite well. Instead, if knowledge of the temperature is required elswh
ere, the tow-dimensional model si needed. The investigation herein presente
d shows that for low-conductivity materials (a-Si) the temperature peaks ar
e placed inside the thin film for the absorption function distribution, det
ermined by interference phenomena.