表面電漿共振型光纖探針之製作改良與其光學特性

Fabrication Improvement of Surface Plasmon Resonance Type Optical Fiber Probes and Their Optical Characteristics

羅健甫(Chien-Fu Lo)

指導教授 ： 王倫

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201700765

摘要

近來，在光纖端面製作次微米金屬結構並應用於表面電漿共振感測十分受到矚目，到目前為止已經發展了許多應用。因此，表面電漿共振光纖探針的需求與日俱增。我們實驗室先前已有利用光纖集束並結合用奈米轉印的方法大量製作表面電漿共振光纖探針的經驗，但先前的結果在量測反射式訊號上遇到問題，原因是轉印在光纖端面的三維形狀網狀結構會阻礙增強的電場與外界環境的互動，導致環境折射率的改變並不會改變反射訊號共振波長的位置。
在此論文中，我們致力於改良光纖探針的製作過程。透過一系列的製程使最終轉印至光纖端面的結構是二維之金屬網狀結構，確保增強後的電場能與外界環境互動進而改變共振波長。此外我們也使用了FDTD Solutions此商業用軟體來研究表面電漿共振光纖探針的光學特性，模擬結果預測了反射與穿透頻譜的趨勢，同時表面電漿共振的位置與特性也被探討與證實。在外界環境的模擬當中發現二維結構的反射頻譜的共振位置確實能隨著環境改變而飄移，這是先前三維結構的所辦不到的。在實驗量測的部分，頻譜量測結果與模擬結果有高度的相似性，證實了模擬模組的可靠性。藉由比較多根光纖的頻譜均一性，暗示了利用奈米轉印技術達成表面電漿共振光纖探針大量製作的潛力。穿透頻譜在折射率感測方面亦有良好的表現，在共振位置之靈敏度為283.4 nm/RIU。

關鍵字

奈米轉印 ； 光纖感測 ； 表面電漿 ； 干涉微影 ； 光纖集束

並列摘要

Recently the fabrication of metallic submicron structures on optical fiber facets and subsequent applications to sensing based on surface plasmon resonance (SPR) has drawn a lot of attentions. Therefore, the need of SPR fiber probes increases steadily. By combining fiber bundles and nanotransfer printing (nTP) method, large-quantity fabrication of SPR fiber probes was realized in our lab in which three-dimensional (3D) nanostructures were transferred into the fiber facts. However, it was difficult to measure the resonance wavelength shifting using such reflection type optical fiber probles because the change of surrounding index could not affect the enhanced electric filed, leading little shift of the resonance wavelength.
In this thesis, we study how to improve the fabrication process for making SPR fiber probes. Through a series fabrication processes, a two-dimensional (2D) hole-array metal nanostructures were transferred into the fiber facets ensuring the enhanced electric field can interact with surrounding environment and thus affect resonance wavelengths. To study the optical characteristics of the SPR fiber probes, a commercial software, FDTD Solutions, were used in this study. The simulated results revealed the trends of the reflection and transmission spectra and the characteristics of SPR were also confirmed and discussed.
In the simulation of different surrounding media, the resonant wavelengths of the reflection spectrumfrom 2D nanostructures shifted as the surrounding media changed while 3D nanostructures do not. In experiment, the measured results showed good consistency with the simulated, which verified the reliability of the models used in the simulation. By comparing the uniformity of fabricated fiber probes, utilizing fiber bundles and nTP technique is found potential for large-quantity fabrication of SPR fiber probes. The reflection type SPR optical fiber probes showed good performance in RI sensing with a sensitivity of 283.4nm/RIU.

並列關鍵字

Nanotransfer printing ； Fiber sensor ； Surface plasmon ； Interference lithography ； Fiber bundle

參考文獻

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