橢圓儀的結構分析與校正

Abstract

橢圓儀是一個簡單的測量樣品光學參數的儀器，其藉由入射光的偏振方向與被樣品反射的反射光之偏振方向來分析樣品的光學特性。我們重建並修改了廠牌為Gaertner Scientific的L117C消光式橢圓儀，且製作擬合光學參數的分析程式。我們使用去極化方向的氦氖雷射當作光源，經由偏振片，補償片，入射至樣品表面。在消光式橢圓儀中，當達到消光條件時，我們可以得到兩個橢圓儀參數：相對振幅衰減φ與相對相位延遲Δ，然後可由兩個橢圓儀參數來計算樣品的光學參數，如複折射率與厚度。當我們更換了橢圓儀大部分的零件並製作電腦程式之後，成功地由矽酸硼玻璃(BK7)與鈮酸鋰晶體的實驗中計算出光學參數。The Ellipsometer is a simple equipment to obtain the optical parameters of measured samples. The polarization angles of incident light and reflected light by sample surface are used to analyze the optical properties of the sample. We modified the Gaertner Scientific’s L117C Ellipsometer, which is a null Ellipsometer. We rebuild the system and rewrite the fitting program. The input light source is a depolarized He-Ne laser. Laser light goes through Polarizer, Compensator, then, incident onto the sample surface. In the Null Ellipsometer, we could obtain the two parameters of Ellipsometer, Relative amplitude diminution, φ, and Relative phase retardation, Δ, when output beam power is null. The optical parameters such as Complex index of refraction and Thickness can be deduced by φ and Δ, the Ellipsometer parameters. We replace all the parts and a computer program to deduced the optical parameters, and we have successfully demonstrated the ellipsometer can deduce the optical parameters BK7 glass and Lithium Niobate single crystals.