本論文提出一種以多次全反射共光程外差干涉技術測量微小位移的方法。當一個具有兩種偏極（S與P偏極）的外差光源以物鏡聚焦在某光學鏡面上，其反射光利用內部全反射技術反射後，以檢偏板個別取出兩個於光束邊界的干涉信號。其相位差值與鏡面離開焦點的距離成正比。藉由兩邊界光之間的相位差值，可直接換算成鏡面的位移量。為了增加此系統之敏感度，我們採用長條稜鏡以增加內部全反射的次數。 本方法有因其光路具有近似共光程結構，故有穩定性高，且組裝架構設置容易，即時量測等優點。其解析度可達0.417nm，量測範圍為約為 。 A novel method for measuring small displacement by use of multiple internal reflections in heterodyne interferometry is proposed. In the dissertation, we can achieve a small displacement only by measuring the variation in phase difference between s- and p-polarization states at the total-internal reflection effect. To improve the sensitivity we increase the number of total internal reflections by using a parallelogram prism. The displacement resolution of the method is batter than 0.4nm. Its measurement range can reach . The method has some merits, for example, a simple optical setup, high resolution, high sensitivity, rapid measurement, and high stability and so on. Its feasibility is demonstrated.
