多切口金纳米圆环阵列光学特性研究

发布时间：2018-01-12 04:11

本文关键词：多切口金纳米圆环阵列光学特性研究　出处：《陕西师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：表面等离激元(surface plasmon, SP)是金属表面自由电子和入射电磁场之间相互作用形成的一种电磁模。依据其表现形式可以将其分为沿着金属表面传输的表面等离极化激元(Surface Plasmon Polaritons, SPPs)和不能传播的局域表面等离激元(Localized Surface Plasmon, LSP)。贵金属纳米粒子的远场和近场特征主要源自纳米粒子的局域表面等离激元共振(Localized Surface Plasmon Resonance, LSPR)。研究发现,金属表面的LSPR特性与金属纳米粒子的形状、大小、组分以及周围媒质等因素有关。此外,LSP在纳米颗粒表面特定区域的电场增强效应,使得许多光学过程的效率显著提高,这一特性使其在表面增强拉曼散射、非线性光学、生物医学等方面有广泛的应用。近年来,金属手性微纳结构在众多领域广泛应用,其表面等离激元共振特性能引发的特殊的光学性质。本论文采用有限元方法研究了多切口金纳米圆环(MSR)阵列、双层多切口金纳米圆环(BMSR)阵列及旋转的BMSR阵列的光学性质。具体内容及结果如下：(1)应用有限元方法研究了MSR阵列的LSPR特性,并研究了偏振状态、结构参数改变对其LSPR特性的影响。结果表明,当入射光偏振角度变化时,MSR阵列的透射光谱不发生改变,但其表面电场强烈依赖于入射光偏振角度。当MSR结构参数改变时,圆弧纵横比发生变化,透射光谱发生红移或蓝移。(2)提出了一种双层结构——BMSR阵列结构,研究其在线偏振光照射下透射谷产生的物理机制,并计算了入射光偏振角度、结构参数改变时其透射光谱的变化。研究表明,双层结构对于单层结构来说,多出一种磁共振模式,该结构在此模式下可以等效为LC回路。入射光偏振角度的变化不影响BMSR阵列的透射光谱。各结构参数改变时,两种共振模式发生红移或蓝移。(3)旋转的BMSR是一种手性结构,本文研究该结构在圆偏振光照射下的圆二色性(circular dichroism, CD)。通过改变下层旋转角度发现较强的CD效应出现在三个波段,对一个CD峰处该结构上下层电流分析得出CD效应产生的原因。此外,我们还研究了结构参数对旋转的BMSR阵列CD效应的影响。
[Abstract]:The surface plasmon (surface plasmon SP) is a kind of electromagnetic modes of interaction formed between the metal surface and the free electron incident electromagnetic field. On the basis of the form can be divided into the metal surface along the transmission surface plasmon polariton (Surface Plasmon, Polaritons, SPPs) and not the spread of localized surface plasmon polaritons (Localized Surface Plasmon, LSP). Noble metal nanoparticles far field and near field characteristics mainly from nanoparticles localized surface plasmon resonance (Localized Surface Plasmon Resonance, LSPR). The study found that the LSPR characteristics and the metal nanoparticles of metal surface shape, size, related components and the surrounding medium etc.. In addition, in the specific area of electric field enhancement effect of LSP nano particle surface, make the efficiency of many optical process significantly improved, this character makes it in surface enhanced Raman scattering, non Linear optics, has been widely used in biomedical fields. In recent years, the chiral metal micro nano structure is widely used in many fields, special optical properties caused by the surface plasmon resonance properties. The nano gold ring incision using the finite element method in this paper (MSR) array, multi incision double gold nanoparticles ring (BMSR) optical properties of array and BMSR array rotation. The contents and results are as follows: (1) the finite element method is applied to study the LSPR characteristics of MSR array, and studied the polarization states and the effect of structure parameters on the LSPR performance. The results show that when the change of the polarization of the incident light angle, transmission spectrum the MSR array is not changed, but the surface electric field is strongly dependent on the polarization of the incident light angle. When changing the MSR structure parameters, arc aspect ratio change, transmission spectral redshift or blueshift. (2) proposed a double The structure of BMSR array structure, study its physical mechanism by a linearly polarized light transmission Valley is generated, the polarization of the incident light angle was calculated, changes in the transmission spectrum of the changing structural parameters. The results show that the double-layer structure for single layer structure, a kind of magnetic resonance mode, the structure of this mode is equivalent to LC loop. Change the polarization of the incident light angle does not affect the transmission spectrum of the BMSR array. Changing the structure parameters, two resonance modes occur red shift or blue shift. (3) the rotation of the BMSR is a chiral structure, this paper studies the structure of the circular polarized light under the irradiation of round two color (circular dichroism CD) by changing the lower rotation angle found strong CD effect appeared in three bands, the structure of upper and lower current cause of the CD effect of a CD peak. In addition, we also study the structural parameters of the spin The effect of the CD effect on the BMSR array.

【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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