本研究係以電光調制器調變氦氖雷射作為外差光源，及麥克森光學系統為架構，輔以雙重表面電漿耦合器之設計，並且結合表面電漿共振檢測之高靈敏度、高解析度優點，建立一套新穎的量測系統。 本論文的主要貢獻為光路設計，其雷射光束經分光鏡(CBS)反射為參考光，另一道穿透光束再經由偏極分光鏡(PBS)後，透射P偏振光入射表面電漿共振裝置，會激發表面電漿波造成光強衰減，再加入四分之一波片與反射鏡，使反射光成為S偏振光：而反射S偏振光經由表面電漿共振裝置、四分之一波片與反射鏡反射形成P偏振光，再經由表面電漿共振裝置激發表面電漿波，其光強也會衰減。再讓此兩光束干涉成為感測訊號，藉以提高訊號對比度。 實驗中，當待測溶液濃度改變時，感測訊號產生相位差載波在調變光源之外差頻率上，將上述參考與感測訊號送入鎖相放大器解調相位差 ，並得出相位差變化與液體濃度變化量之線性關係。 A novel measurement system based on to structure of the Michelson interferometry and the techni1ues of double surface plasmon resonance (SPR) was built up in our Lab. A He-Ne laser modulated by an electro-optical (EO) modulator was used in this system to generate a heterodyne source. This system also preserve the advantages of high sensitivity and high resolution of the SPR. The contrast of the signal received by the photo detector was increased with the aid of the SPR. In these experiments, a phase difference Φ in test signal was generated by change the concentrations of the test resolution. A lock-in amplifier also was used to detect both the reference and test signal and obtain the phase difference Φ which is linearly relates with the change of concentrations of the resolution.
