A general and complete theoretical model of the time-resolved thermal mirror method for the measurement of thermo-optical-mechanical properties of solid materials is developed. The laser-induced temperature profile in a sample and its thermoelastic surface displacement are derived. The center intensity of a probe beam at the detector plane is calculated using the Fresnel diffraction theory. Additionally, simplified models for high and low optical absorption samples are presented, and the suitability of the simplified models is also analyzed. The influence of experimental parameters on the sensitivity of the thermal mirror method is discussed for the optimization of the experimental apparatus. The presented model and the experimental technique can be used to quantitatively determine the physical properties of transparent and opaque solids.

The finite-size effect on the thermal mirror (TM) experiments is described. The time-resolved thermoelastic deformation equation is solved and compared to the semi-infinite solution. To determine the applicability of the semi-infinite model, experiments were performed in optical glasses and the quantitative results compared to both models. The analytical results presented here were found to be in excellent agreement with the numerical finite elemental analysis model. Modeling and experiment showed that the TM transient signal is strongly affected as the sample thickness is reduced. The results of the finite-size model demonstrate that it is intrinsically more accurate to characterize physical properties of low optical absorption thin samples, which suggests that the model and the TM method could even be applied to study very thin films down to the micrometer scale.