THERMAL-DIFFUSIVITY MEASUREMENTS USING LINEAR RELATIONS FROM PHOTOTHERMAL WAVE EXPERIMENTS

We present a methodology to retrieve the thermal diffusivity of bulk h omogeneous samples based on a set of simple linear relations that exis t between two measurable magnitudes in modulated photothermal experime nts. The influence of the photothermal parameters involved (exciting b eam radius and height and radius of the probe beam) is evaluated to as sert the validity of the linear relations. Specifically, we discuss th e thermoreflectance and mirage techniques and their more convenient us e and method, depending on the kind of sample to analyze (solid, liqui d, gas), to obtain the thermal diffusivity.