A Theoretical Study for the Thermal Diffusivity Measurement of Solid Material using Photothermal Displacement Method

광열변위법을 이용한 재료의 열확산계수 측정에 대한 이론적 연구

A complete theoretical treatment of the photothermal displacement technique has been performed for thermal diffusivity measurement in solid materials. The influence of parameters - radius and modulation frequency of pump beam and thickness of material - on the phase lag was studied. The phase decreases up to a certain position, then starts to increase and does have an asymptotic value. The position, where phase has the minimum value, is a function of thermal diffusion length thickness of sample, and radius of pump beam. A new method based on minimum phase lag is described to determine the thermal diffusivity of solid material.