title: Laser induced thermal-wave fields in bilayered spherical solids.
abstract: We present a theoretical model for evaluating solid bilayered spherical samples (surfaces) that are heated by a frequency modulated light beam generating thermal waves. The Green's function method is used as it provides a way of evaluating thermal-wave fields of bilayered spherical structures with arbitrary intensity distributions of incident laser beams. The specific thermal-wave Green's function corresponding to the composite structure has been derived. The characteristics of the thermal-wave field with respect to the thermal diffusivity of the material, the diameter of the sample, the size of the incident beam, and the polar angle at which the thermal-wave field is measured on the surface are presented. Experimental results obtained with laser infrared photothermal radiometry are fitted to the theory and the thermal diffusivities of steel spheres are deduced.
authors.affiliation: Key Laboratory of Modern Optical Technologies of Jiangsu Province, Institute of Modern Optical Technologies, Soochow University, Suzhou, Jiangsu 215006, People's Republic of China.
authors.forename: Guangxi
authors.initials: G
authors.lastname: Xie
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Chen
authors.forename: Chinhua
authors.initials: C
authors.lastname: Wang
authors.forename: Andreas
authors.initials: A
authors.lastname: Mandelis