本論文的目的是使用四步移相解相位法解出在光柵耦合表面電漿共振發生時，因折射率變化所造成反射光的相位變化。在光學實做中，常常都會發現接收端的訊號穩定度被光源本身浮動、整個光學系統樞紐端的光學元件所產生的浮動影響，所以在這種環境干擾下選擇四步移相解相位法是個好的選擇。實驗結果證明該架構是可行的，其靈敏度為1.6*10^2 (度/RIU)，系統解析度為0.048度。 The purpose of the dissertation is to use four-step phase shifting technique to get the phase shift of reflective light caused by the change of refraction index when grating-coupled surface plasmon resonance is processing. Whenever we do an experiment, the signal stability is often interfered by the light source and the pivot optical component. Using four-step phase shifting technique to solve these problems will be a good choose. The structure has been verified workable in our experiment. The experimental results show that the sensitivity is 1.6*10^2 (degree/RIU) and the resolution is 0.048 degree.
