貴金屬納米顆粒聚合體中多重法諾共振效應(yīng)的研究
發(fā)布時(shí)間：2018-07-31 15:38
【摘要】：金屬納米顆粒的局域表面等離激元共振時(shí)能夠呈現(xiàn)出獨(dú)特的電磁場(chǎng)增強(qiáng)和消光效應(yīng)，入射光能量能被強(qiáng)烈局域在金屬表面，利用這局域特性可突破光的衍射極限，已經(jīng)受到越來越多研究者的關(guān)注。當(dāng)兩個(gè)或更多的金屬納米顆粒緊密放置構(gòu)成復(fù)雜納米結(jié)構(gòu)時(shí)，金屬納米顆粒間的等離激元可以通過近場(chǎng)相互作用進(jìn)行耦合，從而產(chǎn)生一系列的等離激元雜化。合理的設(shè)計(jì)納米顆粒的放置方式及控制顆粒間的近場(chǎng)耦合，在復(fù)雜納米結(jié)構(gòu)中就能展現(xiàn)出像法諾共振干涉效應(yīng)。對(duì)于表面等離激元體系中法諾共振不僅能夠有效降低體系輻射衰減，還能將入射光能量更好的局限在結(jié)構(gòu)表面的性質(zhì)，使得光譜更加精細(xì)，并可產(chǎn)生更大的局域場(chǎng)增強(qiáng)，提高體系的傳感性能和非線性效應(yīng)。與單一法諾共振相比，多重法諾共振效應(yīng)的體系可在多個(gè)波段可以同時(shí)調(diào)制光譜，有利于實(shí)現(xiàn)可控的譜線整形，調(diào)整多重法諾共振峰位與之匹配，能在多個(gè)波段處同時(shí)產(chǎn)生較大的局域場(chǎng)增強(qiáng)，從而極大提高表面增強(qiáng)拉曼散射的增強(qiáng)因子，當(dāng)多重法諾共振與不同分子振動(dòng)譜形成匹配，可以實(shí)現(xiàn)不同分子的高效檢測(cè)。因此復(fù)雜納米結(jié)構(gòu)中的法諾共振被廣泛應(yīng)用于生物傳感、光學(xué)開關(guān)、表面增強(qiáng)拉曼散射等領(lǐng)域。 本論文是基于貴金屬納米顆粒的局域表面等離激元共振的特性，利用時(shí)域有限差分法數(shù)值模擬研究了幾種復(fù)雜金屬納米結(jié)構(gòu)中的多重法諾共振現(xiàn)象。主要工作包括： (1)研究了納米環(huán)四聚體和八聚體中的法諾共振現(xiàn)象，分析了相應(yīng)的近場(chǎng)分布，討論了納米環(huán)四聚體和八聚體中法諾共振現(xiàn)象形成的原因，以及通過調(diào)整納米環(huán)間夾角和間距的大小，對(duì)法諾共振的光譜位置和調(diào)制深度進(jìn)行調(diào)諧。利用劈裂納米環(huán)的偶極共振模式與四極共振模式的能隙很小的特點(diǎn)，同時(shí)討論了劈裂納米環(huán)四聚體和八聚體的光學(xué)性質(zhì)，結(jié)果表明相比于納米環(huán)四聚體和八聚體，在劈裂納米環(huán)四聚體和八聚體中能產(chǎn)生更多的法諾共振，相同地調(diào)整納米環(huán)間夾角和間距的大小，能對(duì)法諾共振的光譜位置和調(diào)制深度有更大的調(diào)諧。 (2)利用簡(jiǎn)單地改變?nèi)肷涔馄穹较蚓湍芸刂芁型納米棒的光譜特性和近場(chǎng)分布這一特點(diǎn)，，研究了兩種L型納米棒二聚體在不同入射光偏振角時(shí)的光學(xué)性質(zhì)，并在此基礎(chǔ)上構(gòu)建了復(fù)合納米棒結(jié)構(gòu)和L型納米棒四聚體兩種復(fù)雜結(jié)構(gòu)，研究結(jié)果表明，復(fù)合納米棒結(jié)構(gòu)中能夠產(chǎn)生雙重的法諾共振現(xiàn)象，通過改變納米棒長(zhǎng)度可以對(duì)結(jié)構(gòu)中的法諾共振進(jìn)行調(diào)制，并且可以將結(jié)構(gòu)分解成L型納米棒二聚體和普通納米棒二聚體兩個(gè)部分，通過對(duì)比這兩種二聚體共振峰位置隨納米棒長(zhǎng)度的變化關(guān)系，可直觀的了解復(fù)合納米棒結(jié)構(gòu)中消光光譜的變化。另外對(duì)L型納米棒四聚體研究發(fā)現(xiàn)，由于其結(jié)構(gòu)的旋轉(zhuǎn)對(duì)稱性，其遠(yuǎn)場(chǎng)性質(zhì)不隨入射光偏振方向變化而改變，當(dāng)改變納米棒長(zhǎng)度破壞其結(jié)構(gòu)對(duì)稱性和改變?nèi)肷涔馄穹较驎r(shí)，四聚體中最多能出現(xiàn)三重的法諾共振。
[Abstract]:The local surface of the metal nanoparticles can show unique electromagnetic field enhancement and extinction effect. The incident light energy can be strongly localized on the metal surface. Using this local characteristic can break through the diffraction limit of the light, more and more researchers have paid attention to it. When two or more metal nanoparticles are closely placed. When the complex nanostructures are made up, the plasmons between the metal nanoparticles can be coupled through the near field interaction, resulting in a series of plasmons. A reasonable design of the nanoparticles and the control of the near field coupling between the particles can show a Fano resonance interference effect in the complex nanoscale structure. In the surface plasmon resonance system, the Fano resonance can not only effectively reduce the radiation attenuation of the system, but also limit the energy of the incident light to the properties of the structure surface, which makes the spectrum more fine, and can produce a larger local field enhancement, and improve the sensing and non linear effects of the system. The system of resonance effect can modulate the spectrum at the same time in multiple bands. It is beneficial to realize controllable spectral line shaping and adjust the matching of multiple Fano resonance peaks. It can produce large local field enhancement at multiple bands at the same time, thus greatly improving the enhancement factor of surface enhanced Raman scattering, when multiple Fano resonance and different molecular vibration are used. The dynamic spectrum matching can achieve high efficient detection of different molecules. Therefore, Fano resonance in complex nanostructures is widely used in the fields of biosensing, optical switch, surface enhanced Raman scattering and so on.
This paper is based on the characteristic of local surface plasmon resonance of noble metal nanoparticles. The multiple Fano resonance phenomena in several complex metal nanostructures are studied by the finite difference time domain method. The main work includes:
(1) the Fano resonance phenomenon in the nano-ring four polymer and eight polymer was studied. The corresponding near field distribution was analyzed. The reasons for the formation of the Fano resonance in the nano-ring four polymer and the eight polymer were discussed, and the spectral position and the modulation depth of the Fanno co oscillator were tuned by adjusting the angle and spacing between the nanoscale rings. The optical properties of the split nano ring four polymer and the eight polymer are discussed at the same time in the dipole resonance mode and the quadrupole resonance mode. The results show that the nano ring four polymer and the eight polymer can produce more Fano resonance in the split nano-ring four polymer and eight polymer, and adjust the nanoscale interclips in the same way. The size of the angle and spacing can further adjust the spectral location and modulation depth of the Fano resonance.
(2) by simply changing the polarization direction of the incident light, the spectral and near field distribution of the L nanorods can be controlled. The optical properties of the two L nanorods with different incident light polarization angles are studied. On this basis, the structure of the composite nanorods and the two complex structures of the L nanorod four polymer are constructed. The results show that the composite nanorod structure can produce a double Fano resonance phenomenon. By changing the length of the nanorods, the Fano resonance in the structure can be modulated, and the structure can be decomposed into two parts of the L type nanorod two polymer and the ordinary nanorod two polymer. By comparing the two two polymer resonance peaks with the nanorod length The variation of the extinction spectra in the structure of the composite nanorods can be understood intuitively. In addition, the study of the four polymer of the L nanorods shows that the far-field properties of the nanorods are not changed with the polarization direction of the incident light, and the structure symmetry of the nanorods and the polarization direction of the incident light are changed when the length of the nanorods is changed. At the time, the three fold of the four polymer can be observed.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1;O631
本文編號(hào)：2156032
[Abstract]:The local surface of the metal nanoparticles can show unique electromagnetic field enhancement and extinction effect. The incident light energy can be strongly localized on the metal surface. Using this local characteristic can break through the diffraction limit of the light, more and more researchers have paid attention to it. When two or more metal nanoparticles are closely placed. When the complex nanostructures are made up, the plasmons between the metal nanoparticles can be coupled through the near field interaction, resulting in a series of plasmons. A reasonable design of the nanoparticles and the control of the near field coupling between the particles can show a Fano resonance interference effect in the complex nanoscale structure. In the surface plasmon resonance system, the Fano resonance can not only effectively reduce the radiation attenuation of the system, but also limit the energy of the incident light to the properties of the structure surface, which makes the spectrum more fine, and can produce a larger local field enhancement, and improve the sensing and non linear effects of the system. The system of resonance effect can modulate the spectrum at the same time in multiple bands. It is beneficial to realize controllable spectral line shaping and adjust the matching of multiple Fano resonance peaks. It can produce large local field enhancement at multiple bands at the same time, thus greatly improving the enhancement factor of surface enhanced Raman scattering, when multiple Fano resonance and different molecular vibration are used. The dynamic spectrum matching can achieve high efficient detection of different molecules. Therefore, Fano resonance in complex nanostructures is widely used in the fields of biosensing, optical switch, surface enhanced Raman scattering and so on.
This paper is based on the characteristic of local surface plasmon resonance of noble metal nanoparticles. The multiple Fano resonance phenomena in several complex metal nanostructures are studied by the finite difference time domain method. The main work includes:
(1) the Fano resonance phenomenon in the nano-ring four polymer and eight polymer was studied. The corresponding near field distribution was analyzed. The reasons for the formation of the Fano resonance in the nano-ring four polymer and the eight polymer were discussed, and the spectral position and the modulation depth of the Fanno co oscillator were tuned by adjusting the angle and spacing between the nanoscale rings. The optical properties of the split nano ring four polymer and the eight polymer are discussed at the same time in the dipole resonance mode and the quadrupole resonance mode. The results show that the nano ring four polymer and the eight polymer can produce more Fano resonance in the split nano-ring four polymer and eight polymer, and adjust the nanoscale interclips in the same way. The size of the angle and spacing can further adjust the spectral location and modulation depth of the Fano resonance.
(2) by simply changing the polarization direction of the incident light, the spectral and near field distribution of the L nanorods can be controlled. The optical properties of the two L nanorods with different incident light polarization angles are studied. On this basis, the structure of the composite nanorods and the two complex structures of the L nanorod four polymer are constructed. The results show that the composite nanorod structure can produce a double Fano resonance phenomenon. By changing the length of the nanorods, the Fano resonance in the structure can be modulated, and the structure can be decomposed into two parts of the L type nanorod two polymer and the ordinary nanorod two polymer. By comparing the two two polymer resonance peaks with the nanorod length The variation of the extinction spectra in the structure of the composite nanorods can be understood intuitively. In addition, the study of the four polymer of the L nanorods shows that the far-field properties of the nanorods are not changed with the polarization direction of the incident light, and the structure symmetry of the nanorods and the polarization direction of the incident light are changed when the length of the nanorods is changed. At the time, the three fold of the four polymer can be observed.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1;O631
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本文編號(hào)：2156032
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