如何在納米結構中控制的光的傳播，一直是物理和應用技術方面被廣泛研究的其中一個課題。在這篇論文中，我們從理論上探討在納米結構中表面等離子體激元(Surface plasmon polariton) 的特性以及其雜化。我們研究的納米結構包括金屬電介質金屬平板導波(chirped metaldielectric wave-guides) ，慘入納米金屬球的金屬電介質平板導波(metal dielectric waveguides with metallic narnoparticle doped)與光子晶體(photoniccrystals) 。 / 金屬-電介質-金屬平板導波由三層的金屬及電介質平板所組成，原本各自獨立存在於兩層金屬-介電介面的表面等離子體激元在兩層介面相距足夠近的情況下，會產生稱合作用而導致雜化表面等離子體激元(Hybridizedsurface plasmon polariton) 的產生，並且能在色散關係中被一條接近平坦、位於中頻附近的帶所表示。 / 同樣地，透過在金屬介電介面附近的電介質平板部份中加入納米金屬球，我們也能引起納米金屬球上的表面等離子體與平面金屬-介電介面上的表面等離子體激元之間的耦合作用，從而在色散關係產生另一條分支帶。 / 這些由雜化作用所導致的平坦的分支帶，其特性很容易透過操縱模型參數所改變。因此，我們可以在模型中引入一個介電常數(或厚度)的漸變梯度，從而達成表面等離子體激元的定域化，或多頻率表面等離子體激元(SPP rainbow) 的誘捕。 / 另外，透過轉移距列(transfer matrix)及哈密頓光學(Hamiltonian opticsapproach) 的應用，我們同時研究了表面等離子波在一維二元光子晶體中的斜入射色散關係及其傳播。結果證明，它可以用來引起波長尺度級別的表面等離子波的軌跡彎曲。 / Controlling the light propagation in nanostructures is one of the extensively studied topics in physics and technology. In this thesis, we theoretically investigate the behaviours of surface plasmon polariton (SPP) and the hybridized nanostructures, which include chirped metal-dielectric waveguides, metal-dielectric waveguides with metallic nanoparticle doped and photonic crystals. / In the system of chirped metal-dielectric waveguides which compose of metal-dielectric-metal multilayers, the evanescent coupling of the SPP waves at the two interfaces in the dielectric layer lead to a new hybridized surface plasmon polariton (HSPP) branch with a nearly flat dispersion at intermediate frequencies. / Similarly, by adding metallic nano-particles into the dielectric media, we can also achieve another HSPP branch which is caused by the coupling between the surface plasmon (SP) on the nanoparticles and SPP at the waveguide interface. Moreover, the nearly flat branch is tunable through changing the system parameters. Therefore by imposing a gradual variation of per-mittivity (or thickness), it is possible to achieve a localization of SPP wave, which is useful for achieving trapped SPP rainbow. / We also study at oblique incidence the dispersion relation and the propagation of SP in one dimension binary photonic crystals by using methods of transfer matrix and Hamiltonian optics approach. The result shows that it can be used to achieve a superbending of SP waves in wavelength scales. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chau, Cheung Wai = 表面等離子光學及納米光學中的雜交化電磁極化子 / 鄒長威. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 84-86). / Abstracts also in Chinese. / Chau, Cheung Wai = Biao mian deng li zi guang xue ji na mi guang xue zhong de za jiao hua dian ci ji hua zi / Zou Changwei. / Abstract --- p.i / 概要 --- p.iii / Acknowledgements --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Plasmonics and nanophotonics --- p.1 / Chapter 1.2 --- Surface plasmon polaritons --- p.2 / Chapter 1.2.1 --- History of SPP --- p.2 / Chapter 1.2.2 --- Investigations and applications of SPPs --- p.3 / Chapter 1.3 --- Objective of thesis --- p.3 / Chapter 2 --- Basic principles --- p.5 / Chapter 2.1 --- Drude model --- p.5 / Chapter 2.2 --- SPP formalism --- p.7 / Chapter 2.2.1 --- SPP excitation --- p.9 / Chapter 2.3 --- Level repulsion phenomenon --- p.10 / Chapter 2.3.1 --- Simple coupled oscillator --- p.10 / Chapter 2.3.2 --- Diatomic elastic chain --- p.12 / Chapter 2.3.3 --- Summary --- p.13 / Chapter 2.4 --- Transfer matrix method --- p.14 / Chapter 2.5 --- Hamiltonian optics approach --- p.16 / Chapter 2.6 --- Maxwell Garnett approximation --- p.17 / Chapter 3 --- Thomson plasmonics --- p.20 / Chapter 3.1 --- Introduction --- p.21 / Chapter 3.2 --- Model and scheme --- p.21 / Chapter 3.3 --- HSPP formalism --- p.22 / Chapter 3.4 --- HSPP bands with varying inclusions of metallic nanospheres --- p.23 / Chapter 3.5 --- Confinement scheme --- p.25 / Chapter 3.6 --- HO simulation and localization --- p.26 / Chapter 3.6.1 --- Center excitation --- p.28 / Chapter 3.6.2 --- Off center excitation --- p.30 / Chapter 3.7 --- Tunability and fabrication --- p.31 / Chapter 3.8 --- Complications and loss --- p.33 / Chapter 3.9 --- Summary --- p.33 / Chapter 4 --- Chirped metal-dielectric waveguides --- p.41 / Chapter 4.1 --- Introduction --- p.42 / Chapter 4.2 --- Model and scheme --- p.42 / Chapter 4.3 --- SPP formalism --- p.43 / Chapter 4.4 --- HSPP bands with varying permittivity and thickness --- p.45 / Chapter 4.5 --- Confinement scheme --- p.46 / Chapter 4.5.1 --- Varying permittivity --- p.47 / Chapter 4.5.2 --- Varying thickness --- p.47 / Chapter 4.6 --- Ho simulation and localization --- p.48 / Chapter 4.6.1 --- Varying permittivity --- p.49 / Chapter 4.6.2 --- Varying thickness --- p.51 / Chapter 4.7 --- Summary --- p.53 / Chapter 5 --- Dispersion and mirage of surface plasmon waves in metallic photonic crystals --- p.60 / Chapter 5.1 --- Photonic crystal --- p.60 / Chapter 5.2 --- Introduction --- p.61 / Chapter 5.3 --- Dispersion relation formalism --- p.61 / Chapter 5.4 --- Graded material --- p.64 / Chapter 5.5 --- Ho simulation --- p.65 / Chapter 5.6 --- Results --- p.66 / Chapter 5.6.1 --- Lowest band excitation --- p.66 / Chapter 5.6.2 --- Second lowest band excitation --- p.69 / Chapter 5.6.3 --- Multiangle incidence --- p.71 / Chapter 5.7 --- Summary --- p.72 / Chapter 6 --- Conclusion --- p.82 / Bibliography --- p.84

各種納米結構的光學反應，已成為一被相當關注的課題，在物理理論和應用技術的層面上被廣泛研究。在本文中，我們利用格林函數方法(GFF)，研究了新月形圓柱体和兩接近中的圓柱体的靜電共振。格林函數方法裏涉及一表面積分方程式，我們求該方程的解便可以得出各不同形狀的納米結構的電勢。格林函數方法是一容易使用、高效率的方法，並且在研究納米結構的光學行為的問題上得出準確結果。 / 在論文的第一部分，我們計算了新月形圓柱体和兩接近中的圓柱体的杆光譜，從而研究該兩個結構的靜電共振。然而，當這兩個結構中有接觸點時，系統中便有一奇點，因此我們不能直接使用格林函數方法研究這情況。為了解決這問題，我們首先使用了變換光學的方法，求得該結構的雙極因子，再從中得到其有效介電常數的譜密度。為了比較非接觸情況中離散的杆光譜和接觸情況中的連續杆光譜，我們進一步定義了一累積分佈函數，它是其譜密度的累積分佈函數。我們從而發現當系統由非接觸的情況漸近接觸時，其離散的杆光譜便趨向其相應的連續杆光譜。 / 在論文的第二部分，我們直接研究了新月形圓柱体和兩接近中的圓柱体的勢分佈和電埸分佈。我們發現在新月形圓柱体和兩接近中的圓柱体的系統中，能量會分別將集中於其金屬間隔和空氣間隔附近的區域。當我們適當地選擇系統的參數時，其共振及能量更能進一步增強。我們亦確認了使用格林函數方法和使用保角變換方法兩者得出的結果的是吻合的。我們的研究結果可以幫助設計電漿子捕光裝置。 / The optical responses of various nanostructures have attracted a considerable attention and they have been extensively studied from the theoretical and technological points of view. In this thesis, we have studied the electrostatic resonance of crescent-shaped cylinder and two approaching cylinders by the Green function formalism (GFF). In the GFF, a surface integral equation is formulated for the scalar potential for an arbitrary number of nanostructures of various shapes. GFF is easy to apply and gives accurate results for the optical behaviors of these nanostructures. / In the first part of the thesis, we have studied the electrostatic resonance of crescent-shaped cylinder and two approaching cylinders by calculating the pole spectrum. However, in the touching case, there is a singular point and thus the GFF cannot be applied directly. To circumvent this problem, the spectral density is found from the polarizability of the nanostructure, which can be obtained analytically by the transformation optics approach. To compare the discrete pole spectrum of the non-touching cases with the continuous spectrum of the touching case, we have used the cumulative distribution function of the spectral density. We are then able to show that the discrete pole spectrum approaches to the continuous pole spectrum as the system approaches from non-touching cases to the touching case. / In the second part of the thesis, the electrostatic resonance is investigated by directly finding the local field distributions of crescent and two approaching cylinders under a uniform applied electric field. It is shown that there is an energy concentration within the metal narrow gap and the air narrow gap in the cases of crescent and two approaching cylinders respectively. It is also found that when parameters are carefully chosen, the nanoconcentration of energy will be greatly enhanced. The numerical GFF results are confirmed with the analytic results by conformal transformation. The results are useful in designing plasmonic light-harvesting devices. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yung, Sai Kit = 電漿子納米結構中的能量集中 : 格林函數方法 / 翁世杰. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 71-74). / Abstracts also in Chinese. / Yung, Sai Kit = Dian jiang zi na mi jie gou zhong de neng liang ji zhong : Gelin han shu fang fa / Weng Shijie. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Optical responses in plasmonic systems --- p.1 / Chapter 1.2 --- Objective of the thesis --- p.5 / Chapter 2 --- Review on Green function formalism --- p.7 / Chapter 2.1 --- Integral equation formalism --- p.7 / Chapter 2.2 --- Periodic corrugated interfaces --- p.11 / Chapter 2.3 --- Solution by mode expansion --- p.16 / Chapter 2.4 --- Numerical solution --- p.18 / Chapter 3 --- Pole spectrums of crescent-shaped cylinder and approaching cylinders --- p.21 / Chapter 3.1 --- Review of Green function formalism on the spectral representation of the effective dielectric constant --- p.22 / Chapter 3.2 --- Numerical results --- p.29 / Chapter 3.2.1 --- Spectral representation of the effective dielectric constant of crescent-shaped cylinders --- p.29 / Chapter 3.2.2 --- Spectral representation of the effective dielectric constant of approaching cylinders --- p.37 / Chapter 4 --- Energy concentration of crescent and approaching cylinders --- p.44 / Chapter 4.1 --- Energy concentration of crescent-shaped cylinder --- p.45 / Chapter 4.2 --- Energy concentration of approaching cylinders --- p.53 / Chapter 5 --- Conclusion --- p.58 / Chapter 5.1 --- Suggestion of future works --- p.60 / Chapter A --- Conformal transformation --- p.61 / Chapter A.1 --- Conformal transformation on crescent-shaped cylinder: nontouching case --- p.61 / Chapter A.2 --- Conformal transformation on approaching crescent-shaped cylinders --- p.66 / Bibliography --- p.71

Zhang, Zhongxiang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

We present a theoretical analysis of surface-plasmon-mediated mode-coupling in a planar thin film metal/insulator stack. The spatial overlap of a surface plasmon polariton (SPP) and a waveguide mode results in a Fano interference analog. Tuning of the material parameters effects the modes and output fields of the system. Lastly, the intensity and phase sensitivity of the system are compared to a standard surface plasmon resonance (SPR). We begin with background information on Fano interference, an interference effect between two indistinguishable pathways. Originally described for autoionization, we discuss the analogs in other systems. We discuss the features of Fano interference in the mode diagrams, and the Fano resonance observed in the output field. The idea of a geometric Fano resonance (GFR) occurring in the angular domain is presented. Background information on surface plasmon polaritons is covered next. The dielectric properties of metals and how they relate to surface plasmons is first reviewed. The theoretical background of SPPs on an infinite planar surface is covered. The modes of a two planar interface metal/insulator stack are reviewed and the leaky properties of the waveguide are shown in the reflectance. We solve for modes of a three interface metal/insulator stack and shows an avoided crossing in the modes indicative of Fano interference. We observe the asymmetric Fano resonance in the angular domain in the reflectance. The tunability of the material parameters tunes the GFR of the system. The GFR tuning is explored and different Fano lineshapes are observed. We also observe a reversal of the asymmetry Fano lineshape, attributed to the relate phase interactions of the non-interacting modes. The phase of the GFR is calculated and discussed for the variations of the parameters. The reflected field is explored as the insulator permittivities are varied. As the waveguide permittivity is varied, we show there is little response from the system. As the exterior permittivity is varied, the reflectance exhibits the geometric Fano resonance and the tunability of the lineshape is explored. Finally, we calculate the sensitivities of our metal/insulator stack to changes in the permittivity and compare them to the sensitivities of SPRs.

No description available.

基於局域表面等離子體共振極其敏感于金屬納米結構的尺寸和形貌的特性，貴金屬納米晶體在近些年來受到了研究人員的極大注意。而膠體金屬納米顆粒在共振時表現出極大的光散射和光吸收截面，且存在于金屬表面的電磁場強度也遠遠高於入射光的電磁場強度。膠體顆粒的各種應用已被發掘並廣泛應用於生物醫學領域，比如表面增強拉曼散射、表面增強螢光、基於等離子的傳感及光熱治療等。然而由於金材料的損耗係數大於銀，金納米材料對電磁場的增強效果弱于銀納米材料。傳統的銀納米膠體顆粒的局域表面等離子體共振峰多局限於420~500 nm，而常見的商業雷射器多在500~660 nm範圍內，目前對膠體銀納米顆粒的大小和形狀的可控性研究的報到還很有限，且將銀納米顆粒的共振調控到常用雷射器的波長範圍內對實際的應用有著重大的意義。本篇論文將系統地研究利用光化學方法製備銀納米十面體和相關納米結構，以及他們的等離子體增強效果。 / 首先，我們將介紹各種化學試劑及光源在銀納米顆粒的形成過程中的作用，以及一種能較好的控制銀納米十面體（LSPR：420~660 nm）的大小的方法。我們發現化學試劑和光源對最終納米顆粒的純度和形狀均有影響。比如通過調節硝酸銀和檸檬酸鈉的摩爾比例可以有效的控制被硼氫化鈉還原出來的金屬納米顆粒的晶體結構。465nm的光照能有效地將聚乙烯吡咯烷酮穩定的小金屬銀納米顆粒轉變成納米十面體。如果我們再使用與十面體種子顆粒的LSPR接近的LED作為光源，並用含有大量的金屬銀納米小顆粒溶液做為前驅液，更大的金屬納米十面體顆粒（LSPR：490~590 nm）可以獲得。而另一方面，使用通過離心的方法提純出來的銀十面體作為種子，更大範圍的金屬十面體（LSPR：490~660 nm）可以被生長出來，即使我們只使用了一種光源（500nm LED）。 / 之後，我們研究了銀十面體的光學性質，及它們基於表面增強拉曼散射的低濃度分子探測的應用。相比于其他形狀的金屬納米顆粒，銀納米十面體能得到更強的拉曼信號，這表明銀納米十面體對局域場的增強效果優於其他的顆粒。實驗結果表明，單個金屬納米顆粒的拉曼平均增強係數能達到10⁶。爲了能將銀納米十面體應用於生物傳感和成像領域，我們製備出具有高穩定性和強拉曼信號的表面增強拉曼探針。另一方面，通過表面增強拉曼光譜，銀納米十面體修飾的矽片能靈敏地探測出10⁻⁸ M的4-MBA分子。我們並通過模擬計算的方法證明，在十面體和襯底之間加入介質和導體薄膜能進一步增加其拉曼靈敏度。 / 最後，我們通過光化學方法在襯底上製備出金屬銀納米結構，並得到一些初步的實驗結果。在633nm鐳射的照射下，組裝在玻璃襯底上的小納米顆粒將會轉變由銀納米片組成的納米結構。通過測量，存在于金屬納米結構中的週期只有幾個微米，這也充分的表明通過光化學的方法，我們可以在襯底上製備出由銀納米顆粒組成的任意結構。拉曼光譜可以作為一種實時觀測銀納米結構生長和表面增強拉曼“熱點形成的有效手段。 / Noble-metal nanocrystals have received considerable attention in recent years for their size and shape dependent localized surface Plasmon resonances (LSPR). Various applications based on colloidal nanoparticles, such as surface enhanced Raman scattering (SERS), surface enhanced fluorescence (SEF), plasmonic sensing, photothermal therapy etc., have been broadly explored in the field of biomedicine, because of their extremely large optical scattering and absorption cross sections, as well as giant electric field enhancement on their surface. However, despite its high chemical stability, gold exhibits quite large losses and electric field enhancement is comparatively weaker than silver. Silver nanoparticles synthesized by the traditional technique only cover an LSPR ranged from 420~500 nm. On the other hand, the range of 500~660 nm, which is covered by several easily available commercial laser lines, very limited colloidal silver nanostructures with controllable size and shape have been reported, and ealization of tuning the resonance to longer wavelengths is very important for the practical applications. In this thesis, a systematic study on photochemical synthesis of silver nanodecahedrons (NDs) and related nanostructures, and their plasmonic field enhancements are presented. / First, the roles of chemicals and the light source during the formation of silver nanoparticles have been studied. We have also developed a preparation route for the production size-controlled silver nanodecahedrons (LSPR range 420~660 nm) in high purity. Indeed our experiments indicate that both the chemicals and the light sources can affect the shape and purity of final products. Adjusting the molar ratio between sodium citrate and silver nitrate can help to control the crystal structure following rapid reduction from sodium borohydride. Light from a blue LED (465 nm) can efficiently transform the polyvinylpyrrolidone stabilized small silver nanoparticles into silver NDs through photo excitation. These silver NDs acting as seeds can be re-grown into larger silver NDs with LSPR ranging from 490 nm to 590 nm, upon receiving LED irradiation with emission close to the LSPR of silver ND seeds, which are suspended in a precursor solution containing small silver nanoparticles. With the aid of centrifugation, silver NDs with high purity can be obtained. Furthermore, silver ND with a broad tuning range (LSPR 490~660 nm) can be synthesized from these seeds using irradiation from a 500 nm LED. / Second, the optical properties of silver NDs and their SERS application for sensitive molecular detection are presented. Raman signal obtained from silver NDs show remarkable advantage over noble nanoparticles of other shaped, thus revealing their strong localized field enhancement. Experimental results demonstrate that average enhancement factor from individual silver ND may be as high as 10⁶. In order to explore their application for biosensing and bioimaging, stable silica coated SERS tags based on silver ND producing high Raman intensity have been studied. Our experiment results indicate that 10⁻⁸ M 4-MBA in solution can be detected by silver NDs modified silicon chip through SERS. Simulation result on the geometry of silver ND/silica spacer/gold film/substrate shows that the Raman sensitivity of the NDs modified chip can be further improved with the insertion of a dielectric/conductor film between them. / Finally, we present a photochemical method for the preparation of silver nanostructures preparation with the use of 633 nm laser. Silver nanostructures composed of silver nanoplates could be grown from small silver nanoparticles deposited on a glass substrate. The periodicity of the silver nanostructures is several micrometers, revealing that this photochemical method has the potential for “writing“ silver pattern on a solid substrate. Raman spectroscopy has also been explored for real-time monitoring of silver nanostructure growth and SERS hotspots formation. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Lu, Haifei. / "December 2012." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 122-140). / Abstract also in Chinese. / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Chemical synthesis of noble nanoparticles --- p.1 / Chapter 1.1.1 --- Nucleation --- p.4 / Chapter 1.1.2 --- Evolution from Nuclei to Seeds --- p.5 / Chapter 1.1.3 --- Evolution from Seeds to Nanocrystals --- p.9 / Chapter 1.2 --- Theoretical background of localized surface plasmon (LSP) --- p.14 / Chapter 1.2.1 --- Determination of the dielectric constant --- p.15 / Chapter 1.2.2 --- Maxwell equations --- p.20 / Chapter 1.2.3 --- Quasi static approximation --- p.21 / Chapter 1.2.4 --- Gans Theory --- p.22 / Chapter 1.2.5 --- Mie theory --- p.23 / Chapter 1.2.6 --- Numerical methods --- p.25 / Chapter 1.3 --- Structure of this thesis --- p.29 / Chapter Chapter 2. --- Optical properties of noble nanoparticles and their biomedical applications --- p.30 / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- LSPR of nanoparticles with different shapes and different material composition --- p.30 / Chapter 2.4 --- Local field enhancement of nanoparticles and their effects to Raman and fluorescence --- p.35 / Chapter 2.5 --- Noble nanoparticles for biomedical applications --- p.38 / Chapter 2.5.1 --- Noble nanocrystals for diagnostics --- p.38 / Chapter 2.5.2 --- Noble nanocrystals for cellular and in vivo bioimaging --- p.41 / Chapter 2.5.3 --- Noble metal nanocrystals in medicine --- p.43 / Chapter Chapter 3. --- Photochemical synthesis of size controlled silver nanodecahedrons (NDs) --- p.46 / Chapter 3.1 --- Introduction --- p.46 / Chapter 3.2 --- Seed mediated plasmon driven regrowth of silver nanodecahedrons . --- p.47 / Chapter 3.3 --- Chemical roles of reagents in the process and mechanism for photogrowth of silver nanodecahedrons --- p.55 / Chapter 3.4 --- Light wavelength effect to the regrowth of silver NDs --- p.63 / Chapter 3.5 --- Control on the crystal defects of small silver nanoparticles and effect of precursor to the regrowth of various size silver NDs --- p.67 / Chapter 3.6 --- Summary --- p.77 / Chapter Chapter 4. --- SERS assessment of silver nanodecahedrons and their application for sensitive detection based on SERS --- p.78 / Chapter 4.1 --- Introduction --- p.78 / Chapter 4.2 --- Investigation on SERS of silver NDs and other nanoparticles --- p.79 / Chapter 4.3 --- Silica coated SERS tags with silver NDs as the core --- p.85 / Chapter 4.4 --- Silver nanodecahedrons for biosensing --- p.93 / Chapter 4.5 --- Summary --- p.101 / Chapter Chapter 5. --- Photochemical growth of Plasmonic nanostructures on solid substrate --- p.103 / Chapter 5.1 --- Introduction --- p.103 / Chapter 5.2 --- Experimental --- p.104 / Chapter 5.3 --- Result and discussion --- p.105 / Chapter 5.3.1 --- Photochemical growth of silver nanostructures by laser irradiation through a single slit --- p.105 / Chapter 5.3.2 --- SERS characterization of silver nanostructures --- p.110 / Chapter 5.3.3 --- Observation of photochemical growth of silver nanostructures --- p.112 / Chapter 5.4 --- Summary --- p.115 / Chapter Chapter 6. --- Conclusion and outlook --- p.117 / References --- p.122

Fang, Caihong = 基於表面等離子體基元的微流芯片光熱技术和金納米棒-納米球二聚體中的表面等離子體基元共振耦合 / 房彩虹. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Abstracts in English and Chinese. / Fang, Caihong = Ji yu biao mian deng li zi ti ji yuan de wei liu xin pian guang re ji shu he jin na mi bang-na mi qiu er ju ti zhong de biao mian deng li zi ti ji yuan gong zhen ou he / Fang Caihong. / Abstract --- p.i / 摘要 --- p.iv / Acknowledgement --- p.vi / Table of Contents --- p.viii / List of Figures --- p.x / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Temperature Control on Microfluidic Chips --- p.2 / Chapter 1.1.1 --- Introduction to Microfluidics --- p.2 / Chapter 1.1.2 --- Temperature Control on Microfluidic Systems and Its Applications --- p.5 / Chapter 1.1.2.1 --- Heating Applications on Microfluidic Chips --- p.5 / Chapter 1.1.2.2 --- Heating/Cooling Methods in Microfluidic Systems --- p.7 / Chapter 1.1.2.3 --- Temperature Measurements in Microfluidic Systems --- p.10 / Chapter 1.2 --- Plasmonic Properties of Noble Metal Nanocrystals --- p.14 / Chapter 1.2.1 --- Localized Surface Plasmon Resonances of Noble Metal Nanocrystals --- p.15 / Chapter 1.2.2 --- Photothermal Conversion of Gold Nanocrystals --- p.19 / Chapter 1.2.3 --- Plasmon Coupling in Gold Nanocrystals --- p.21 / Chapter 1.3 --- Motivation and Outline of the Thesis --- p.23 / References --- p.24 / Chapter 2. --- Growth of Gold Nanocrystals and Characterization Techniques --- p.33 / Chapter 2.1 --- Growth of Au Nanocrystals Samples --- p.33 / Chapter 2.2 --- Characterization Techniques --- p.36 / References --- p.40 / Chapter 3 --- Plasmonic Heating Using Gold Nanorod-Embedded poly(dimethylsiIoxane --- p.43 / Chapter 3.1 --- Embedding Gold Nanorods with Varying Plasmon Resonance Wavelengths into Poly(dimcthylsiloxanc) (PDMS) --- p.43 / Chapter 3.2 --- Plasmonic Heating using Gold Nanorod-Embedded PDMS --- p.54 / Chapter 3.2.1 --- Photothermal Conversion of the Gold Nanorod-Embedded PDMS --- p.54 / Chapter 3.2.2 --- Temperature Measurements Using Rhodaminc B --- p.56 / Chapter 3.2.3 --- Plasmonic Heating and Temperature Measurements on Microfluidic Chips --- p.60 / Chapter 3.2.4 --- Flow Switching Based on the Gold Nanorod-Embedded-PDMS Microfluidic Chips --- p.63 / Chapter 3.3 --- Summary --- p.67 / References --- p.69 / Chapter 4 --- Surface Plasmon Coupling in Gold Nanorod-Nanosphere Heterodimers --- p.73 / Chapter 4.1 --- Preparation of Gold Nanorod-Nanosphere Heterodimers --- p.74 / Chapter 4.2 --- Plasmon Coupling in Gold Nanorod-Nanosphere Heterodimers --- p.77 / Chapter 4.2.1 --- Experimental Results --- p.77 / Chapter 4.2.2 --- Electrodynamic Calculations --- p.82 / Chapter 4.3 --- Summary --- p.89 / References --- p.90 / Chapter 5 --- Summary and Conclusion --- p.93 / Chapter 6 --- Curriculum Vitae --- p.95

Abstract not available

In this thesis, the spectral behavior of the fundamental and sum-frequency waves, generated from the surface of a thin metal film in the Kretschmann configuration, is theoretically studied with coherent ultrashort pulses. As a first exploration of considering spectral response in nonlinear plasmonics, it is shown that the spectra of reflected sum-frequency waves exhibit pronounced shifts for the incident fundamental waves close to the plasmon coupling angle, whereas meanwhile those of reflected fundamental waves display energy holes. We also demonstrate that the scale of discovered plasmon-enhanced spectral changes is strongly influenced by the magnitude of the incidentce angle and the source pulse duration, and at a certain angle a spectral switch is observed. The appearance of large sum-frequency wave shifts can serve as an unambiguous plasmon signatur in nonlinear surface spectroscopy. Also, the discovered spectral switch can trigger extremely surface-sensitive nonlinear plasmonic sensors.

Pour la première fois, en associant un microscope à effet tunnel (STM) et un microscope optique inversé,nous avons imagé les plasmons de surface excités électriquement sur un film d'or avec la pointe d'un STM.Par microscopie de fuite radiative, en observant l'image de l'interface air/or et celle du plan de Fourierassocié, nous avons distingué les plasmons propagatifs des plasmons localisés sous la pointe. Les plasmonspropagatifs sont caractérisés par une distance de propagation et une direction d'émission en accord aveccelles de plasmons propagatifs créés par excitation laser sur des films d'or de mêmes épaisseurs. Les fuitesradiatives des plasmons localisés s'étalent jusqu'à l'angle maximum d'observation. Plasmons propagatifs etlocalisés ont une large bande spectrale dans le visible. Si la pointe est plasmonique (en argent), lesplasmons localisés ont une composante supplémentaire due au couplage associé. Pour différents types depointe, nous avons déterminé les intensités relatives des plasmons localisés et propagatifs. Nous trouvonsque chaque mode plasmon (propagatif ou localisé) peut être préférentiellement sélectionné en modifiant lematériau de la pointe et sa forme. Une pointe en argent produit une intensité élevée de plasmons localisés,tandis qu'une pointe fine de tungstène (rayon de l'apex inférieur à 100 nm) produit essentiellement desplasmons propagatifs. Nous avons étudié la cohérence spatiale des plasmons propagatifs excités par la pointe du STM. Avec un film d'or opaque (épaisseur 200 nm) percé de paires de nanotrous nous avons réalisé une expérienceanalogue à celle des fentes d'Young. Des franges d'interférences sont observées. La mesure de leurvisibilité en fonction de la distance des nanotrous donne une longueur de cohérence des plasmons de 4.7±0.5 μm. Cette valeur, très proche de la valeur 3.7± 1.2 μm déduite de la largeur de la distribution spectraledes plasmons, indique que l'élargissement spectral des plasmons propagatifs est homogène.Nous avons aussi étudié la diffusion des plasmons propagatifs excités par la pointe du STM par desnanoparticules d'or déposées sur un film d'épaisseur 50 nm. Nous observons une diffusion élastique et unediffusion radiative. Des franges d'interférences sont observées dans la région d'émission lumineuseinterdite du plan de Fourier, dont la période est inversement proportionnelle à la distancepointe-nanoparticule d'or avec un facteur de proportionnalité égal à la longueur d'onde moyenne desplasmons. Il y a donc interférence entre la radiation des plasmons localisés et la radiation provenant de ladiffusion des plasmons propagatifs sur les nanoparticules d'or. Ceci indique que les plasmons localisés etpropagatifs excités électriquement par la pointe du STM sont différentes composantes du plasmon uniqueproduit par effet tunnel inélastique avec la pointe du STM. Ces résultats originaux sur les plasmons créés sur film d'or par un effet tunnel inélastique localisé à l'échelle atomique (i) élargissent la compréhension du processus et (ii) offrent des perspectives intéressantes pour une association de la nanoélectronique et de la nanophotonique.