Comment on “Experimental comparison of methods based on falling and rising signal regions for thermal diffusivity measurement by pulsed dual-beam thermal lens spectroscopy”

Abstract In Ref. Mohebbifar (2020), the author used the mode-mismatched thermal lens (TL) technique under pulsed excitation and a model developed for continuous-wave excitation (CW) mode to fit the experimental data. Using no clear procedure of reference sample, thermal diffusivity (thermal conductivity) in a set of fluid samples were artificially obtained. Here, we showed analytically that the proposed model and the corresponding TL transient are not compatible with the thermal diffusion theory.