J. Phys. IV France 125 (2005) 157-160
DOI: 10.1051/jp4:2005125036

About the effective thermal and optical parameters of a two-layer structure in photothermal phenomena

N. Muñoz Aguirre¹, L. Martínez Pérez^{2, 3}, V. Garibay-Febles¹ and M. Lozada-Cassou<sup>1

1</sup>  Programa de Ingeniería Molecular del Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152, Mexico DF 07730, Mexico
²  Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del Instituto Politécnico Nacional, Legaria 694, Mexico DF 11500, Mexico
³  Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas del Instituto Politécnico Nacional, Av. IPN No. 2580, Mexico DF 07340, Mexico

Abstract
IThe model for the calculation of effective thermal parameters in two-layer structure in photoacoustic phenomena proposed in previous works [1-4] is used for defining and calculating the effective optical parameters. The concept of effective optical absorption coefficient will naturally emerge from the model when a heat source, depending on the position and the optical absorption coefficient, is taken into account. Results for the static limit shows that, in general case, the effective optical absorption coefficient value depends on the effective thermal conductivity, and it is different for rear-surface and front-surface illumination configurations. For optically opaque samples in rear-illumination configuration and optically transparent layers, it is show that the effective optical absorption coefficient and the effective thermal conductivity are independent and can be separately obtained. The latter result suggests for optically transparent samples, it will be correct to use the Maxwell Equations for defining and calculating the effective optical parameters in multilayer structures.

© EDP Sciences 2005