表面電漿共振(surface plasmon resonance,SPR)是一種對表面結構、金屬性質、介質特性等的變化非常敏感的金屬、電磁波交互作用現象。
液晶是一種具有各向異性(anisotropic)特質的材料，在光學上光線通過液晶所感受到的折射率與光的行進方向、偏振方向有所關聯。本實驗使用摻雜了1205偶氮染料的偶氮液晶(azo-LCs)，此種液晶具有光調變的特性，即透過特定波長的激發光進行照射，可改變液晶的相態與排列狀態，使其具有不同的光學特性。在1205偶氮液晶相變過程中會產生微小顆粒，這些微顆粒造成了入射光的米氏散射現象。
我們對偶氮液晶於金屬光柵上的表面電漿波特性十分的感興趣，因此我們將具有雙折射性的偶氮液晶鋪在金屬光柵基板上，藉由偶氮液晶的光調變特性作為控制表面電漿波耦合的開關，利用液晶的相態變化過程中產生的米氏散射現象，使得入射金屬光柵上之水平波向量得以與kspp匹配，來達到調變表面電漿共振模態之目的。

Surface plasmon resonance (SPR) is sensitive to the surface structure, metal properties and refractive index of the upper layer.
Liquid crystal is anisotropic material. In optics, the refractive index varies with the direction of the light entering the liquid crystal. 5CB liquid crystal doped with 1205 azo-dyes is used in the experiment. The azo-LC layer could be switched between isotropic and nematic phases by irradiating with UV laser or green laser. Liquid crystal micro domains (formed between isotropic and nematic phases) were generated during phase transition process. These micro domains caused Mie scattering.
In this research, we injected the azo-LC into a liquid crystal cell with aluminum metallic grating, and used 1205 azo-LC as a switch to control the coupled of surface plasmon resonance. During the phase change process of azo-LC, the micro particles appears in the azo-LC layer. And this micro particles caused Mie scattering effect to the incident light. The Mie scattering effect to the incident light provides much horizontal k-vectors on metal surface and increases the probability for the light to couple the surface plasmon resonance.

致謝 ii
摘要 iii
Abstract iv
目錄 v
圖次 viii
表次 xi
1 第一章 序論 1
1.1 前言 1
1.2 研究動機與文獻回顧 1
1.3 論文架構 2
2 第二章 理論介紹 3
2.1 表面電漿波 3
2.1.1 全反射與消逝波 4
2.1.2 金屬的光學性質 5
2.1.3 金屬表面之表面電漿共振模態 10
2.1.4 表面電漿共振激發架構 15
2.2 液晶 19
2.2.1 液晶分類 19
2.2.2 液晶的物理特性 21
2.2.3 光引致染料分子 25
2.3 米氏散射 27
第三章 實驗方法與步驟 31
3.1 樣品製備 31
3.1.1 ITO玻璃基板上奈米金屬光柵之製備 31
3.1.2 液晶盒之製備 34
3.1.3 偶氮苯染料液晶 36
3.2 量測架構與方法 37
第四章 結果與討論 38
4.1 金與鋁之介電系數及色散曲線之比較 38
4.2 金屬薄膜上金屬光柵之波向量水平分量 39
4.3 光引致液晶調控鋁金屬光柵之表面電漿模態分析 41
4.3.1 光學顯微鏡架構下之量測 41
4.3.2 自由空間下之量測 46
4.3.3 鎳金屬光柵之量測 50
第五章 結論 52
參考文獻 53

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