Photodeflection signal formation in photothermal measurements: comparison of the complex ray theory, the ray theory, the wave theory, and experimental results.

A comparison is made of three methods for modeling the interaction of a laser probe beam with the temperature field of a thermal wave. The three methods include: (1) a new method based on complex ray theory, which allows us to take into account the disturbance of the amplitude and phase of the electric field of the probe beam, (2) the ray deflection averaging theory of Aamodt and Murphy, and (3) the wave theory (WT) of Glazov and Muratikov. To carry out this comparison, it is necessary to reformulate the description of the photodeflection signal in either the WT or the ray deflection averaging theory.

Measurement of the thermal diffusivity of dental filling materials using modified Angström's method.

Objectives: A new measuring technique for the determination of thermal diffusivity is proposed. Using this technique, the thermal properties of a few different dental filling materials were measured.

Methods: The proposed method for measurement of thermal diffusivity is based on the classical Angström's method.