表面热透镜技术应用于薄膜微弱吸收测量的理论和实验

Theory and experiment of surface thermal lens technique used in absorption measurement of thin films

由薄膜表面光热形变简化理论和表面热透镜衍射理论导出表面热透镜信号表达式,从理论上证明了表面热透镜信号和薄膜吸收率的线性关系.应用表面热透镜技术研制了薄膜吸收测量仪,测量结果表明其吸收率测量灵敏度和精度均达10-6量级.

The expression of surface thermal lens（STL） signal is deduced from photothermal deformation theory of thin film surface and STL diffraction theory. The linearity of STL signal to absorption of thin film can be seen from the expression. A measurement apparatus for thin film absorption based on STL technique is constructed. The measuring results prove that the sensitivity and accuracy of this instrument reach 10^-6 magnitude.