R. Kato et al., DEVELOPMENT OF AC CALORIMETRIC METHOD FOR THERMAL-DIFFUSIVITY MEASUREMENT .5. MODULATED LASER-BEAM IRRADIATION, JPN J A P 1, 32(8), 1993, pp. 3656-3658
In an ac light-irradiation method for measuring thermal diffusivity al
ong the length of the rectangular thin film sample, we developed a met
hod which uses a modulated laser beam. The laser beam was swept with a
high frequency so as to cover the width of the sample. Such a procedu
re makes possible to obtain uniform ac thermal energy distribution in
the direction perpendicular to the direction of ac temperature-wave pr
opagation. Furthermore, it gives rise to a nonuniform ac thermal energ
y distribution in the direction along the direction of ac temperature-
wave propagation. It is theoretically proven that the latter inhomogen
eity does not affect the determination of thermal diffusivity. This fa
ct is verified by experiment.