Iu, Hei = 二維週期性金屬納米共振腔的理論研究 / 姚熙. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 89-91). / Abstracts in English and Chinese. / Iu, Hei = Er wei zhou qi xing jin shu na mi gong zhen qiang de li lun yan jiu / Yao Xi. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Introduction to Surface Plasmon Polaritons --- p.3 / Chapter 2.1 --- The Maxwell´ةs Equations --- p.3 / Chapter 2.2 --- Photonic crystals --- p.5 / Chapter 2.3 --- Modeling Metal --- p.9 / Chapter 2.4 --- Surface plasmon polarition --- p.12 / Chapter 3 --- Rectangular Cavity --- p.17 / Chapter 3.1 --- Basic simulation cell setup --- p.17 / Chapter 3.2 --- Method of mode identification --- p.18 / Chapter 3.2.1 --- Dispersion relation calculation --- p.18 / Chapter 3.2.2 --- Reflection spectra --- p.19 / Chapter 3.3 --- Results and discussions --- p.20 / Chapter 4 --- Nano-bottle cavity --- p.25 / Chapter 4.1 --- Cylindrical cavity --- p.25 / Chapter 4.1.1 --- Dispersion relations calculation --- p.25 / Chapter 4.1.2 --- Field pattern calculation --- p.29 / Chapter 4.2 --- Nano-bottle cavity --- p.46 / Chapter 4.2.1 --- The effect of the bottleneck on (0，1) mode --- p.47 / Chapter 4.2.2 --- The effect of aperture size on (0，1) mode --- p.58 / Chapter 4.2.3 --- The effect of the depth of cavities on (0，1) mode --- p.62 / Chapter 4.2.4 --- "The effect of aperture size on (-1,0) mode" --- p.63 / Chapter 4.3 --- Discussions --- p.64 / Chapter 4.4 --- Verified with experimental results --- p.68 / Chapter 5 --- Aspect ratio --- p.71 / Chapter 5.1 --- Simulation structure --- p.72 / Chapter 5.2 --- Aspect ratio S = 2 --- p.73 / Chapter 5.3 --- The effect of aspect ratio --- p.74 / Chapter 5.3.1 --- Orientation dependence of the resonant mode --- p.74 / Chapter 5.3.2 --- Excitation frequency of the resonant mode --- p.75 / Chapter 5.4 --- Field location and strength --- p.76 / Chapter 5.5 --- Discussions --- p.77 / Chapter 5.6 --- Comparison with experimental results --- p.79 / Chapter 6 --- Conclusions and future works --- p.83 / Chapter 6.1 --- A possible new mode excitation --- p.84 / Chapter 6.2 --- Cavities with aspect ratio under p-polarized light --- p.86 / Bibliography --- p.89 / Chapter A --- Computational Simulation --- p.92 / Chapter A.l --- Finite-Difference Time-Domain --- p.92 / Chapter A.2 --- Computational grid --- p.93 / Chapter A.3 --- Boundary Condition --- p.93 / Chapter A.4 --- Source --- p.94 / Chapter A.5 --- Field strength --- p.94

Lei, Dangyuan = 表面等離子交叉耦合協助氧化鋅發射的理論和實驗研究 / 雷黨願. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 81-85). / Abstracts in English and Chinese. / Lei, Dangyuan = Biao mian deng li zi jiao cha ou he xie zhu yang hua xin fa she de li lun he shi yan yan jiu / Lei Dangyuan. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivations --- p.1 / Chapter 1.2 --- Thesis outline --- p.3 / Chapter 2 --- Background and Proposition --- p.7 / Chapter 2.1 --- Surface plasmon mediated emission from semiconductor --- p.7 / Chapter 2.1.1 --- General mechanism --- p.7 / Chapter 2.1.2 --- Formulation of SP coupling --- p.10 / Chapter 2.1.2.1 --- Derivation of dispersion relation --- p.10 / Chapter 2.1.2.2 --- Plasmonic density of states (DOS) --- p.13 / Chapter 2.1.2.3 --- Field distribution in dielectric/metal/dielectric System --- p.13 / Chapter 2.1.2.4 --- Determination of Purcell factor (Fp) --- p.16 / Chapter 2.1.3 --- Emission enhancement from metal-capped ZnO --- p.17 / Chapter 2.2 --- Proposal for making high efficiency top-emitting LED --- p.22 / Chapter 3 --- Experimental Setup and Measurement System --- p.24 / Chapter 3.1 --- Sample preparation --- p.24 / Chapter 3.1.1 --- Radio frequency magnetron sputtering --- p.24 / Chapter 3.1.2 --- Spin-coating --- p.27 / Chapter 3.1.3 --- Rapid thermal annealing --- p.29 / Chapter 3.2 --- Optical characterizations --- p.29 / Chapter 3.2.1 --- Transmittance measurement --- p.29 / Chapter 3.2.2 --- Photoluminescence (PL) measurement --- p.31 / Chapter 3.2.3 --- EDX for composition measurement --- p.32 / Chapter 4 --- Theoretical Simulations and Experimental Results --- p.36 / Chapter 4.1 --- Tunable surface plasmon resonance by using metal alloys --- p.36 / Chapter 4.1.1 --- Dielectric constants calculation --- p.37 / Chapter 4.1.2 --- Dispersion relation of alloy/Si02 --- p.41 / Chapter 4.1.3 --- Plasmonic density of states and Purcell factor of alloy/semiconductor --- p.43 / Chapter 4.1.3.1 --- Air/AlxAg1-x/ZnO system --- p.43 / Chapter 4.1.3.2 --- Air/AlxAul-x/ZnTe --- p.46 / Chapter 4.1.3.3 --- Air/ AgxAul-x/CdSe system --- p.48 / Chapter 4.1.4 --- Experimental results of AlxAgl-x/ZnO --- p.52 / Chapter 4.1.5 --- Discussion and mini-conclusion --- p.56 / Chapter 4.2 --- Enhanced forward emission from metal-insulator-metal/ZnO by coupled surface plasmon --- p.57 / Chapter 4.2.1 --- Plasmon modes in metal-insulator-metal (MIM) --- p.57 / Chapter 4.2.2 --- Transmittance simulation of MIM and MIMIM --- p.63 / Chapter 4.2.3 --- Transmittance measurement of MIM --- p.68 / Chapter 4.2.4 --- Transmittance and photoluminescence of MIM/ZnO. --- p.73 / Chapter 4.2.5 --- Discussion and mini-conclusion --- p.78 / Chapter 5 --- Conclusions --- p.79 / Chapter 6 --- References --- p.81

In complex plasmonic nanostructures, the multiple metal-dielectric interfaces support several elementary modes of surface plasmon polariton. Hybridized surface plasmon polariton (HSPP) is formed due to the evanescent coupling between surface plasmon polaritons on different interfaces. In our first work, we studied the properties of HSPP in a metal-dielectric-metal waveguide with periodically varying refractive index, using Hamiltonian optics approach. We investigated the feasibility of light manipulation inside this structure by extracting the allowed phase orbits using the proposed quantization condition. Besides, the time series of position and wavevector of HSPP are simulated by solving the Hamiltonian equations. The result revealed three distinct HSPP modes formed inside the waveguide: confinement, propagation and retardation. Lastly, we investigated the usage of the proposed structure as an optical filter. / Nearly perfect absorption (NPA) refers to a phenomenon that the reflection and transmission of incident electromagnetic waves on a system are being suppressed, thus the energy of waves is being trapped and dissipated in the system. In our second work, a design of broadband, wide angle of incidence and polarization-independent nearly perfect absorber is proposed based on multiple surface plasmon resonances. The absorptance is computed to confirm NPA for TM and TE modes. Besides, the absorptance depends also on the thickness of the composite layer and this dependence is explained by the hybridized surface plasmon (HSP) formed inside the absorber. Particularly for TE mode, the broadband HSP fast wave which coupled efficiently with the incident light, can only be generated for proper thickness of the composite layer, in contrast to the previous proposal of fast wave generation mechanism using metal/epsilon-near-zero structure to yield narrow-band NPA by S.Feng. The proposed absorber can be used to construct light harvesting devices because of its high efficient energy absorption. / 在複合的等離子納米結構中的多個金屬-電介質介面能支持數個表面等離子激元(surface plasmon polariton)的基礎模態。而雜交化表面等離子激元(hybridized surface plasmon polariton)就是不同表面上的表面等離子激元因衰減性耦合而形成的。在我們第一個工作中,我們以哈密頓光學(Hamiltonian optics)研究了在有週期性折射率變化的金屬-電介質-金屬波導中雜交化表面等離子激元的特性。我們以所提出的量化條件析取出容許的相位軌跡,從而探究在此結構中操縱光波的可行性。此外,雜交化表面等離子激元的位置和波向量隨時間的變化會通過解哈密頓方程計算出來。結果顯示在此波導中,雜交化表面等離子激元有三種不同的模態:密閉,傳播,延滯。最後,我們探討了此結構作為光學過濾器的應用。 / 近完全吸收(Nearly perfect absorption)是指射在一系統上的電磁波的反射和傳輸都被壓制,而波的能量則被困鎖和消耗在系統中的一個現象。在我們第二個工作中,我們提出了一個基於多重表面等離子元共振的寬頻、廣入射角、與偏振無關的近完全吸收器設計。我們計算了吸引率以確認在TE及TM模態下的近完全吸收。此外,吸引率亦與複合層的厚度有關,而此關係能以在吸收器形成的雜交化表面等離子解釋。特別是TE模態時,能有效地與入射光耦合的寬頻雜交化表面等離子快波(Broadband HSP fastwave)只能在合適的厚度才能產生,與S.Feng所提出以金屬/近零介電常數材料結構產生快波,從而達至窄頻近完全吸收不同。因為高效能的能量吸引,我們提出的吸收器能作建構光收集裝置之用。 / Lee, Sze Fung = 在等離子吸收器中基於多重表面等離子元共振的寬頻近完全吸收 / 李時鋒. / Thesis M.Phil. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 58-62). / Abstracts also in Chinese. / Title from PDF title page (viewed on 24, October, 2016). / Lee, Sze Fung = Zai deng li zi xi shou qi zhong ji yu duo chong biao mian deng li zi yuan gong zhen de kuan pin jin wan quan xi shou / Li Shifeng. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

With the development of ultra-fast laser technology, several new imaging techniques have pushed optical resolution past the diffraction limit for traditional light-based optics. Advancements in lithography have enabled the straightforward creation of micron- and nanometer-sized optical devices. Exposing metal-dielectric structures to light can result in surface plasmon excitation and propagation along the transition interface, creating a surface plasmon polariton (SPP) response. Varying the materials or geometry of the structures, the plasmonic response can be tailored for a wide range of applications. Photoemission electron microscopy (PEEM) has been used to image excitations in micron-sized plasmonic devices. With PEEM, optical responses can be characterized in detail, aiding in the development of new types of plasmonic structures and their applications. We show here that in thin, triangular gold platelets SPPs can be excited and concentrated within specific regions of the material (thickness ~50 nm); resulting in localized photoemission in areas of high electric field intensity. In this regard, the platelets behave as receiver antennas by converting the incident light into localized excitations in specific regions of the gold platelets. The excited areas can be significantly smaller than the wavelength of the incident light (λ≤1µ). By varying the wavelength of the light, the brightness of the excited spots can be changed and by varying the polarization of the light, the brightness and position can be changed, effectively switching the photoemission on or off for a specific region within the triangular gold structure. In this work, the spatial distribution of surface plasmons and the imaging results from photoemission electron microscopy are reproduced in simulation using finite element analysis (FEA). In addition, we show that electromagnetic theory and simulation enable a detailed and quantitative analysis of the excited SPP modes, an explanation of the overall optical responses seen in PEEM images, and prediction of new results.

The purpose of this study was to prepare concentrated and stable gold colloids for the enhancement of the signal response of the SPR technique for detecting small molecules such as progesterone. The gold colloids developed in this study were prepared by hydrazine hydrate, sodium borohydride, and tri-potassium citrate reduction routes. The study revealed that the sodium borohydride reduced gold colloids were extremely stable and it was able to be utilised in the progesterone immunoassay developed previously by Mitchell et al. The experiment was carried out on BIAcore 3000 using two different sensor surfaces (CM5 and SAM). The results showed that the enhancement species prepared from the borohydride-reduced gold colloids were able to improve the SPR signal response by 13 times higher than SPR signal produced without the enhancement species on the CM5 surface. The signal enhancement on the SAM surface using the same enhancement species was even greater at 29 times higher. The sensitivity of the assay was, however, unable to be determined due to time constraint. The limit of detection (LOD) of the progesterone assay using the CM5 chip was estimated to be ca. 5-20 pg/mL. Whilst for the SAM chip, the LOD of the progesterone assay was estimated to be ca. 5-20 fg/mL. Further work is required to confirm these estimated LOD values.

The interactions of biomolecules and cells at solid-liquid interfaces play a pivotal role in a range of biomedical applications and have hence been studied in detail. An improved understanding of these interactions results in the ability to manipulate biomolecules and concurrently cells spatially and temporally at surfaces with high precision. Spatial control can be achieved using patterned surface chemistries whilst temporal control is achieved by switchable surfaces. The combination of these two surface properties offers unprecedented control over the behaviour of biomolecules and cells at the solid-liquid interface. This is particularly relevant for cell microarray applications, where a range of biological processes must be duly controlled in order to maximise the efficiency and throughput of these devices. Of particular interest are transfected cell microarrays (TCMs), which significantly widen the scope of microarray genomic analysis by enabling the high-throughput analysis of gene function within living cells Initially, this thesis focuses on the spatially controlled, electro-stimulated adsorption and desorption of DNA. Surface modification of a silicon chip with an allylamine plasma polymer (ALAPP) layer resulted in a surface that supported DNA adsorption and sustained cell attachment. Subsequent high density grafting of poly(ethylene glycol) (PEG) formed a layer resistant to biomolecule adsorption and cell attachment. PEG grafted surfaces also showed significantly reduced attachment of DNA with an equilibrium binding constant of 23 ml/mg as compared with 1600 ml/mg for ALAPP modified surfaces. Moreover, both hydrophobic and electrostatic interactions were shown to contribute to the binding of DNA to ALAPP. Spatial control over the surface chemistry was achieved using excimer laser ablation of the PEG coating which enabled the production of patterns of re-exposed ALAPP with high resolution. Preferential electro-stimulated adsorption of DNA to the ALAPP regions and subsequent desorption by the application of a negative bias was observed. Furthermore, this approach was investigated for TCM applications. Cell culture experiments demonstrated efficient and controlled transfection of cells. Electro-stimulated desorption of DNA was shown to yield enhanced solid phase transfection efficiencies with values of up to 30%. The ability to spatially control DNA adsorption combined with the ability to control the binding and release of DNA by application of a controlled voltage enables an advanced level of control over DNA bioactivity on solid substrates and lends itself to biochip applications. As an alternative approach to surface patterning, the fabrication and characterisation of chemical patterns using a technique that can be readily integrated with methods currently used for the formation of microarrays is also presented. Here, phenylazide modified polymers were printed onto low fouling ALAPP-PEG modified surfaces. UV irradiation of these polymer arrays resulted in the crosslinking of the polymer spots and their covalent attachment to the surface. Cell attachment was shown to follow the patterned surface chemistry. Due to the use of a microarray contact printer it was easily possible to deposit DNA on top of the polymer microarray spots. A transfected cell microarray was generated in this way, demonstrating the ability to limit cell attachment to specific regions and the suitability of this approach for high density cell assays. In order to allow for the high-throughput characterisation of the resultant polymer microarrays, surface plasmon resonance imaging was utilised to study the adsorption and desorption of bovine serum albumin, collagen and fibronectin. This analysis enabled insights into the underlying mechanisms of cell attachment to the polymers studied. For the system analysed here, electrostatic interactions were shown to dominate cellular behaviour.

Antithrombin (AT) is one of the most important anticoagulant factors in the blood, and its effects are increased by the interaction with glycosaminoglycans, especially heparin. AT appears in two additional variants, other than the native form, and those variants have antiangiogenic properties and also bind to heparin. AT is found in two distinct isoforms (alfa, beta) where the difference lie in the degree of glycosylation. This project has shown interesting results regarding the dependence of calcium ions on the binding between heparin and antithrombin. The results show that the beta-isoform increases its affinity for heparin in the presence of calcium in contrast to the alfa-isoform, which shows a decrease in the heparin affinity under the same conditions. This project has also given results that after further investigation and development could be used for an improved set-up of the immobilisation of AT variants in a surface plasmon resonance system. The results show that immobilisation of a protein in the reference channel gives a better shielding effect between the negatively charged heparin molecules and the negatively charged dextran matrix. Furthermore a more significant difference was seen between the two heparin moieties used during binding affinity studies, especially for native AT.

Heat shock protein 70 (HSP70) is an important health related biomarker, being implicated as an early stage cancer marker and as an indicator of cardiac health. It also has important implications in wildlife environmental monitoring, as its levels can be affected by food deprivation, elevated temperatures, and pollution. Therefore, the use of HSP70 as a biomarker is highly desirable, yet the current methods of quantifying HSP70 are time consuming, expensive, and require dedicated labs. In order to facilitate widespread use of the HSP70 biomarker, a quantification tool that can be used at the point-of-care is needed. This implies the development of a simple and inexpensive HSP70 biosensing technique that is highly sensitive and selective. Therefore, in this work a label-free HSP70 biosensor has been designed based on the optical properties of gold nanoparticles (NPs). Gold NPs exhibit a large absorbance peak in the visible spectrum due to localized surface plasmon resonance (LSPR). The peak position is dependent on the local refractive index, which can be employed as a biosensor by selectively capturing the target analyte to the NP surface. To design an LSPR HSP70 sensor, optical and fluidic simulations were developed to determine optimal NP geometries and microchannel dimensions. The results showed optimal response when using 100nmx5nm gold nanotriangles inside of a 100μmx100μm microchannel. Simulations of the sensor performance showed HSP70 detection from 0.92-4000ng/ml with a resolution of 1.1ng/ml, all of which satisfied the design requirements. An LSPR sensor was experimentally tested at the benchtop scale to prove the concept. Gold NPs were fabricated by electron beam lithography and enclosed in a polymer flow cell. For initial testing of the LSPR sensor, the NPs were functionalized with biotin for selective capture of streptavidin. Streptavidin was detected in real time over the range 55-500,000ng/ml. The use of bovine serum albumin (BSA) was shown to be necessary to block non-specific binding sites to ensure a streptavidin-specific response. The LSPR sensor was then demonstrated to detect salmon HSP70 at 4600ng/ml using its synthetic antibody. Overall, these results demonstrate that LSPR can be used to realize an HSP70 biosensor suitable for point-of-care applications.

Structure-specific recognition of nucleic acids is a promising method to reduce the size of the recognition unit required to achieve the necessary selectivity and binding affinity for small molecules. It has been demonstrated recently that G-quadruplex DNA structures can be targeted by organic cations in a structure-specific manner. Structural targets of quadruplexes include the planar end surfaces of the G-tetrad stacked columns as well as four grooves. The significant structural differences between quadruplex DNA and duplex DNA make quadruplex DNA a very attractive target for highly selective, structure-specific drug design. We have used a variety of biophysical techniques including circular dichroism, surface plasmon resonance, thermal melting and absorbance spectroscopy to investigate small molecules that can selectively bind to the ends of human telomeric DNA as well as the ends of the G-quadruplex structure formed by the purine-rich promoter region of the c-MYC oncogene. We have also screened a library of heterocyclic diamidines, and identified one that binds selectively in the grooves of human telomeric quadruplex DNA. This compound is an excellent starting point for the design of new anti-cancer and anti-parasitic compounds with high affinity and selectivity for human telomeric DNA.

Surface plasmon polaritons are electromagnetic surface waves coupled to electron plasma oscillation of metals at a metal-dielectric interface. At optical frequencies, these modes are of great interest because of their high confinement to a metal-dielectric interface. Due to the field enhancement at the interface, they have been used in different applications such as sensors, second harmonic generation and enhanced Raman scattering. Surface plasmon resonance based sensors are being used for detection of molecular adsorption such as DNA and proteins. These sensors are known to be highly sensitive and have successfully become commercialized. Terahertz (THz) frequency band of electromagnetic spectrum has attracted researchers in the last few years mostly because of sensing and imaging applications. Many important chemical and biological molecules have their vibrational and rotational resonance frequencies in the THz range that makes the THz sensing one of the most important applications of THz technology. Considering above mentioned facts, extending the concept of surface plasmon sensors to THz frequencies can result in sensitive sensors. In this work the possibility of this extension has been investigated. After reviewing optical surface plasmon polariton waves and a basic sensor configuration, surface plasmon polariton waves propagating on at metallic and doped semiconductor surfaces have been examined for this purpose. It has been shown that these waves on metallic surfaces are loosely confined to the metal-dielectric interface and doped semiconductors are also too lossy and cannot meet the requirements for sensing applications. Afterwards, it is shown that periodically patterned metallic surfaces can guide surface waves that resemble surface plasmon polariton waves. A periodically patterned metallic surface is used to guide THz surface plasmon polariton-like surface waves and a highly sensitive sensor is proposed based on that. The quasi-optical continuous wave (CW) THz radiation is coupled to this structure using the Otto's attenuated total reflection (ATR) configuration and the sensitivity of the device is discussed. A general scattering parameter based model for prism coupling has been proposed and verified. It is shown that a critical coupling condition can happen by changing the gap size between the prim and periodic surface. Details of fabrication of the periodic structure and experimental setup have also been presented.