應用於中紅外波段感測的侷限型表面電漿共振型元件之製作與特性

Abstract

近來，製作奈米金屬粒子結構並應用於侷限型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。我們實驗室先前已有利用奈米轉印的方法製作表面電漿共振元件的經驗，但應用皆只有在可見光波段，往中紅外等長波長的應用顯得較為新穎。 在此論文中，我們致力於週期性奈米金屬粒子的製作。透過創新的製程將奈米金粒子製作在矽基板上以及D型矽核光纖上。此外我們也使用了FDTD Solutions此商業用軟體來研究侷限型表面電漿共振元件的光學特性，模擬結果預測了穿透頻譜，同時侷限型表面電漿共振的位置與特性也被探討與證實。在折射率量測上，我們感測不同濃度的葡萄糖水溶液，且我們的元件也隨改變濃度有波長飄移的現象。在中紅外的指紋訊號也發現有被侷限型表面電漿共振所增強的現象。

Recently the fabrication of metallic nano-structures and subsequent applications to sensing based on localized surface plasmon resonance (LSPR) has drawn a lot of attentions. By nanotransfer printing (nTP) method, fabrication of quality SPR sensors was realized in our lab. However, the applications were limited in the visible range, so extension to mid-infrared is attractive. In this thesis, we study how to fabricate metallic nanodisks. Through a novel fabrication process, the periodic metallic nanodisks were made onto silicon chip and D shaped silicon core fiber. To simulate the optical characteristics of the LSPR sensors, a commercial software, FDTD Solutions was used in this study. The simulated results revealed the trends of the measured transmission spectra and the characteristics of LSPR were also confirmed and discussed. In refractive index sensing, various concentrations of glucose solution were under test, and the resonant wavelengths of the spectra shifted as the concentration changed. The fingerprint signal in mid infrared range was enhanced by LSPR.