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International audience; A recent paper [Guo et al., J. Appl. Phys. 121, 095101 (2017)] intends to demonstrate that from the photothermal radiometry signal obtained on a coated opaque sample in 1D transfer, one should be able to identify separately the following three parameters of the coating: thermal diffusivity, thermal conductivity, and thickness. In this comment, it is shown that, in the considered experiment arrangement, these three parameters are correlated, the identifiability criterion is in error, and the thickness inferred therefrom is not trustable.; Un article récent [X. Guo, A. Mandelis, J. Tolev et K. Tang, J. Appl. Phys., 121, 095101 (2017)] prétend démontrer que, à partir du signal de radiométrie photothermique obtenu sur un échantillon avec un revêtement opaque et en condition transfert thermique 1D, on devrait pouvoir identifier séparément les trois paramètres suivants du revêtement: sa diffusivité thermique, sa conductivité thermique et son épaisseur. Dans ce commentaire, il est par contre démontré que, dans l'arrangement expérimental considéré, les trois paramètres sont en fait corrélés et que le critère d'identification utilisé est erroné.

International audience; In this numerical study, a photothermal method with random excitation is implemented in order to measure the thermal diffusivity of thermally fragile materials. The principle of this technique is based on rebuilding the sample impulse response through input-output cross-correlatoin. A D-optimality criterion is used to determine the optimal duration of the experiment. The thermophysical properties are identified through the rebuilt impulse response using an iterative method which minimizes the gap between simulated measurements and theoretical temperature calculated using the thermal quadripoles method. The obtained results show a good agreement with literature values.