發(fā)布時間：2018-05-01 14:07

  本文選題：表面等離激元 + Fano共振　； 參考：《山東師范大學》2017年碩士論文

【摘要】：金屬納米結構的表面等離激元不僅有很多獨特的性質,而且能夠在納米尺度上操控光,因而受到廣泛關注。表面等離激元對金屬結構的幾何參數、對周圍介電環(huán)境的變化非常敏感,而且在其周圍可形成較強的局域電場,被廣泛的應用于化學生物傳感器、表面增強拉曼散射、熒光增強等方面。本文主要研究了基于金屬納米結構表面等離激元的Fano共振在Nanoruler以及在增強表面拉曼散射中的應用。金屬納米結構的Fano共振可形成譜線較窄的共振模式,對結構參數的變化更為敏感,而且會形成較強的局域電場,能夠提高Nanoruler的探測靈敏度及增強拉曼信號的強度。主要完成的工作如下:(1)基于金屬納米結構的Nanoruler,一般是通過其支持的表面等離激元共振峰的移動去判別生物大分子等在納米尺度范圍內的變化。由于表面等離激元較寬的共振線寬,當結構間距或者幾何參數改變時,共振峰的移動不易被分辨,從而導致其靈敏度不高。Fano共振可形成線寬較窄的共振模式,因此對于參數的變化非常敏感。本文第一個工作主要利用COMSOL軟件設計了一個基于Fano共振的二維Nanoruler,通過計算表明它對于金屬納米結構之間的距離、旋轉角度的變化都十分敏感。此結構由棒和矩形同心環(huán)盤結構組成。我們主要研究了矩形納米盤移動時,對Fano共振峰及其深度的影響。當盤沿水平方向移動時,Fano共振的位置移動了 0.05eV,比其他結構靈敏度提高了 3-4倍。在豎直方向移動時,Fano共振的位置移動了 0.025eV。當盤旋轉不同角度時,Fano共振的位置移動了 0.08eV。當將矩形環(huán)改為非對稱結構時,我們還能判斷出盤具體的移動和旋轉方向。這大大提高了二維Nanoruler的靈敏度。(2)第二個工作主要研究了棒-棒結構及金屬球-球結構所支持的Fano共振現象。通過調節(jié)棒的長度,或者當金屬棒的厚度時,Fano共振都會隨之發(fā)生移動。根據其移動規(guī)律,可以將此結構Fano共振移至633nm的拉曼激光波長處,這對我們實驗有很好的指導作用。而對于雙金屬球的納米結構,我們設計了大小不同的兩個球。通過分別改變兩個小球的直徑以及兩球之間的間距得到散射光譜隨之變化的規(guī)律及電場分布圖。通過電場分布圖我們發(fā)現,隨著小球直徑的減小,拉曼的增強的熱點增加。隨后,我們通過高溫退火的條件制備了金的雙金屬球的SERS基底,并對不同濃度的R6G溶液進行了檢測。結果表明,此結構可提高拉曼散射的信號強度。
[Abstract]:The surface isoexcitons of metal nanostructures not only have many unique properties, but also can manipulate light at nanometer scale, so they have attracted much attention. Surface isoponitons are very sensitive to the geometric parameters of metal structures and can form a strong local electric field around them. They are widely used in chemical biosensors and surface enhanced Raman scattering (SERS). Fluorescence enhancement and so on. In this paper, the application of Fano resonance based on surface isoexcitons of metal nanostructures in Nanoruler and enhanced surface Raman scattering is studied. The Fano resonance of metal nanostructures can form a narrower resonance mode, which is more sensitive to the change of structural parameters, and can form a strong local electric field, which can improve the detection sensitivity of Nanoruler and enhance the intensity of Raman signal. The main works are as follows: (1) Nanoruler based on metal nanostructures is generally used to identify the changes of biomolecules in the nanoscale range by moving the resonance peaks of the surface isoexcitators supported by them. Because of the wide resonance linewidth of the surface isopotons, the shift of the resonance peak is not easy to be distinguished when the structure spacing or geometric parameters are changed, which leads to the low sensitivity of the resonance. Fano resonance can form a narrower resonant mode. Therefore, it is very sensitive to the change of parameters. The first work of this paper mainly uses COMSOL software to design a two-dimensional nanoruler based on Fano resonance. The calculation shows that it is very sensitive to the distance between metal nanostructures and the change of rotation angle. This structure consists of rod and rectangular concentric ring disk structure. We mainly study the effect of the rectangular nanodisk moving on the Fano resonance peak and its depth. When the disk moves horizontally, the position of Fano resonance shifts by 0.05 EV, which is 3-4 times higher than that of other structures. The position of Fano resonance moves 0.025 EV when moving vertically. The position of Fano resonance moves 0.08eV when the disk rotates at different angles. When the rectangular ring is changed to an asymmetric structure, we can also determine the specific movement and rotation direction of the disk. This greatly improves the sensitivity of two-dimensional Nanoruler. (2) the second work mainly studies the Fano resonance phenomena supported by the rod-bar structure and the metal-ball structure. By adjusting the length of the rod, or when the thickness of the metal rod, the Fano resonance will move with it. According to its moving law, the Fano resonance of this structure can be shifted to the Raman laser wavelength of 633nm, which is a good guide to our experiment. For the nanostructures of bimetallic spheres, we designed two spheres of different sizes. By changing the diameter of the two spheres and the distance between the two spheres, the law of the scattering spectrum and the distribution of the electric field are obtained. It is found that the hot spots of Raman enhancement increase with the decrease of the diameter of the sphere. Subsequently, the SERS substrate of gold bimetallic spheres was prepared by high temperature annealing, and the R6G solution with different concentrations was detected. The results show that this structure can improve the signal intensity of Raman scattering.
【學位授予單位】：山東師范大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB383.1

【參考文獻】

相關博士學位論文 前1條

1 韓德專;表面等離子體激元在周期結構中的能帶及傳播性質[D];復旦大學;2006年

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本文編號：1829682