本研究利用雙折射外差干涉術開發一種大範圍且具高精度的角度偵測技術，可應用於角度定位系統。P與S偏光通過雙折射晶體時，其相位差變化對入射角極為靈敏。外差干涉儀可精密地擷取兩偏振光的相位變化，以達到量測角度的目的。同時，我們設計一種新穎光路，以稜鏡將光線導入雙折射晶體，可提高相位對於入射角的靈敏度。於此研究中，我們開發了兩套角度量測系統，分別為線偏光系統與旋光系統。兩系統皆為共光程的架構，可有效地降低環境的干擾。根據實驗結果，線偏光系統的解析力為1.2×10-4° (量測範圍: -20°~3°)。旋光系統的解析力為3×10-5° (量測範圍¬:¬¬±2.5×10-3°)。最後我們整合了角度量測、步進驅動與回授控制裝置，完成了角度定位系統。其定位精度可達1×10-3°，定位範圍20°。

The birefringence heterodyne interferometry for the angular measurement and position is presented. The advantage of the instrument is the large measurement range and high resolution. When p- and s-polarized beams pass through a birefringence crystal, the phase difference between these two polarized beams is sensitive to the incident angle. We can determine the angular variation with the heterodyne interferometer which can precisely detect the phase difference between these two polarized beams. Moreover, a new optical path is designed to enhance the sensitivity by means of prism which couples the light to the birefringence crystal. There are two measurement modes in our system, linear and circular polarized modes. The experimental results show that the resolution of linear polarized mode is 1.2×10-4° (measurement range: -20°~3°) and the resolution of circular polarized mode is 3×10-5° (measurement range: ±2.5×10-3°). Besides, we built an angular positioning system with 1×10-3° accuracy and 20° positioning range by means of an angular measurement system, a step motor and a feedback controller.

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