利用二氧化鈦塗佈在光纖感測器上改善靈敏度及波長控制之研究

THE STUDY OF SURFACE PLASMON RESONANCE OPTICAL FIBER- 400 m SENSORS BASED ON TiO2 COATING FOR SENSITIVITY IMPROVEMENT AND WAVELENGTH CONTROL IN SENSING

劉星甫(Hsing-Fu Liu)

指導教授 ： 蔡五湖

大同大學/電機資訊學院/光電工程研究所/碩士(2010年)

摘要

表面電漿共振技術已被廣泛的應用在化學及生物的特性和分子量級的交互作用檢測上。傳統的表面電漿共振感測技術擁有高的靈敏度、動態變化的即時測量能力、以及在生物感測上無須標地等優點。光纖本身擁有體積小、成本低、並且和表面電漿共振理論相同架構。本論文結合光纖優點與多層膜之微結構，可用來檢測介面上的折射率或薄膜厚度的微小變化。
本論文使用光纖蕊心（Core）較粗的特殊光纖（Fiber-400 m）作為感測器之平台，利用奈米厚度之介電質膜與金膜所製作而成的SPR光纖感測器，可調變表面電漿共振感測器之共振吸收波長區域。與傳統單層金膜SPR光纖感測器之比較，可將原本在600 nm-700 nm共振吸收波段的表面電漿共振感測器，調變至光纖通訊常用波長區間（1310 nm-1550 nm）。具此結構之SPR光纖感測器除了明顯能與現有光纖通訊網路整合，建立多點多工智慧型感測系統之應用外，並可提高SPR感測之靈敏度與增大波長位移量測的範圍。實驗結果顯示，TiO2/Au多層膜結構，其TiO2 濺鍍層的厚度為40 nm時，SPR光纖感測器對酒精和 NaCl 水溶易折射率檢測最佳靈敏度可達3.47×10-6的折射率單位。

關鍵字

SPR光纖感測器 ； 多層膜

並列摘要

Surface Plasmon Resonance（SPR）technique has been widely used in the chemical and biological properties and molecular interaction detection. Conventional SPR sensors have the advantages of high sensitivity, real-time dynamic measurement capability, and in the biological sensing without the use of labels. Besides, fiber itself has small size, low cost, and high compatibility with the requirement of SPR sensing and applications. In this paper, the SPR fiber sensors we proposed enable us to combine the advantages of optical fiber and multilayer SPR sensing structure to develop a new type of SPR fiber sensor, for detecting the small refractive index change of the medium or monitoring the thickness during the nano thin film deposition.
The multi-mode fiber we proposed in this paper with the core diameter of 400 m is prepared as a sensor platform, for the SPR measurement after the multi-layer TiO2/Au films were coated on the side-polished surface. We adjust the thickness of TiO2 film that coated on the Au thin film surface to shift the guided light SPR absorption from the ordinary region of the wavelength of 600-700 nm to the region of 1300-1550 nm that normally uses for the optical fiber communication. The SPR fiber sensors possessing SiO2/Au multi-layer structure can easily be integrated with existing optical fiber communication network as a smart fiber sensing system. Besides, the multi-layer structure we proposed can also enhance the SPR sensing sensitivity as well as increase the dynamic range of the SPR dip wavelength measurement. The experiment results show that the optimal sensitivity of the refractive index detection for the DI water and NaCl solution exhibits the ability as low as 3.47 10-6 a.u., with the thickness of the TiO2 layer of 40 nm coated on the Au film surface.

並列關鍵字

SPR fiber sensor ； multilayer

參考文獻

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