Remote Sensing of the Thermal Diffusivity and the Absorption Coefficient at the Excitation Wavelength of Protective Coatings and Thin Film Materials

A front-face flash-monitoring method for remote sensing of the thermal diffusivity and of the absorption coefficient at the excitation wavelength of thin film materials is presented. Such a method relies on the surface transient temperature vs. time curve initiated by a short-duration heating pulse that is followed by time intervals during which the temperature response sensitively depends on absorption coefficient and thermal diffusivity. An analytical solution of the problem has been derived to solve the inverse heat transfer problem and, by comparison with a numerical experiment, to check the accuracy of the proposed algorithm for obtaining absorption coefficient at the excitation wavelength and thermal diffusivity. The accuracy of the proposed method is better than 0.1%.