光柵耦合表面電漿共振感測器之高靈敏度相位偵測技術研究

Study on The High Sensitivity Phase Detection Technique for Grating-Coupled SPR Sensor

張智皓(Chih-Hao Chang)

指導教授 ： 郭文凱

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2011年)

摘要

本論文主要研究光柵耦合表面電漿共振的相位變化，並嘗試以不同結構、不同待測物檢視相位偵測的靈敏，並力求能達到極高的靈敏度。利用軟微影與奈米壓印技術翻印光柵，在光柵上方以熱蒸鍍法蒸鍍一層金(Au)，即完成光柵耦合表面電漿的元件，為能偵測相位變化，使用外差干涉技術(Heterodyne interferometer)搭配鎖相放大器記錄元件的相位變化，藉由Labview自動化程式，結合步進馬達、光功率計、鎖相放大器及電腦做全自動量測，搭配市售的模擬軟體EMexplorer與Gsolver並且對光柵週期、金屬厚度與調制深度的不同對相位作探討，以達到最佳的靈敏度。實驗的部分首先驗證相位偵測靈敏度會優於強度偵測，接著以不同金屬厚度與調制深度的光柵耦合元件做相位量測，其中不同金屬厚度更以葡萄糖溶液改變介電層的折射率，於此實驗中得到相位偵測靈敏度約為1.5×10-6 RIU。除了金屬厚度及調變深度之外，提出具方位角之光柵耦合組態感測器，偵測靈敏度可達6.025×10-8 RIU。於實驗中發現改變架構中分析片的角度似乎會對於相位響應曲線造成影響，此部分除了有實際的實驗之外，也利用數學計算以佐證實驗的正確性，並在此以氦氣做為待測物，於實驗中所能達到稜鏡耦合最佳的相位偵測靈敏度約為2.1×10-7 RIU。

關鍵字

表面電漿共振感測器 ； 相位偵測

並列摘要

In this thesis, study on grating coupled surface plasmon resonance phase response, and try to use the different analysis to get the phase sensitive detection, and strive to achieve high sensitivity. Using soft lithography and nanoimprint technology to reprint grating, and the gold was deposited on the grating by the thermal evaporation method, the grating-coupler surface plasmon components is complete. In order to detect phase changes, use the heterodyne interferometry and lock-in amplifier to record phase change. Combined with Labview automated program, stepper motors, power meter, lock-in amplifier and computer to automatic measurement. With commercially available simulation software EMexplorer and Gsolver study on the different grating pitch, metal thickness and the phase modulation height in order to achieve the high sensitivity. In the experiment, first we examine the phase detection sensitivity is better than the intensity detection, and then use the different metal thickness and different modulation height of the grating coupled device to do the phase measurement, and use the different metal thickness to change the dielectric layer refractive index through glucose solution, in this experiment that we got the best detection sensitivity is about 1.5×10-6 RIU. And then, this paper adopt the grating-coupled sensor which with the azimuth angle, the best detection sensitivity reach to 6.025×10-8 RIU. In the experiment, it was found that change the analyzer in the structure will affect the phase response curve, this section adopt the numerical result to substantiate the correctness of the experiment, and in this case use the helium as Test gas, in this experiment phase detection can achieve the best sensitivity is about 2.1 × 10-7 RIU.

並列關鍵字

Surface Plasmon resonance sensor ； phase detection

參考文獻

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