利用Mirage方法量測非等向性薄板的熱擴散係數

Abstract

本論文利用Mirage方法量測非等向性薄板的熱擴散係數，文中建立一個三維的熱擴散方程式，並且利用Mirage 飄移量(deflection)來找到熱擴散係數和飄移量的關係，進而找出此方法逆運算沿平面和垂直平面方向熱擴散係數的技巧。此量測方法是利用一道雷射光加熱，另一道雷射光則偵測空氣介質的折射率分佈的不均勻，藉由偵測光經過空氣介質，量測光經過介質的飄移現象推導出物體的熱擴散係數。理論分析顯示：薄板的光學和熱物理性質都會影響熱擴散係數的量測，並且偵測的雷射光與薄板的相對位置和雷射光的光束大小也會對熱擴散係數的量測有影響，這些因素之影響在本論文中均被加以詳細討論。

This thesis purposes to establish the measurement theory of anisotropic thermal diffusivity components for platelike samples by photothermal deflection spectroscopy (Mirage method). The main focus of the tasks will be on two subjects. One is the complete formulation of three-dimensional heat transport phenomenon in association with the photothermal deflection (mirage effect) technique for a platelike sample. The other is the use of mirage method for measuring the anisotropic thermal diffusivity components for platelike samples. In the measurement theory, the relation of the photodeflection versus thermal diffusivity components would be derived and the influence of the optical property of the platelike sample be analyzed. Furthermore, the effects of the height of probe beam, the size of the pumping beam will also be analyzed. In addition, the effect of thermal diffusivity components of anisotropic platelike samples on the measurements of the properties associated with the mirage method is discussed.