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published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Tsang Hing Wa = 梯度粒子系統的扭轉運動 / 曾慶華. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 66-68). / Text in English; abstracts in English and Chinese. / Tsang Hing Wa = Ti du li zi xi tong de niu zhuan yun dong / Zeng Qinghua. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Localization --- p.1 / Chapter 1.1.1 --- Localization by Potential Confinement --- p.1 / Chapter 1.1.2 --- Localization by Interference --- p.2 / Chapter 1.2 --- Graded Materials --- p.2 / Chapter 1.3 --- Rotational Motion --- p.3 / Chapter 2 --- Torsional Motion of Rotating Particles with Graded Couplings / Chapter 2.1 --- Linear Couplings --- p.5 / Chapter 2.1.1 --- Model and Formalism --- p.5 / Chapter 2.1.2 --- Gradient in Coupling Constant --- p.7 / Chapter 2.1.3 --- Gradient in Moment of Inertia --- p.8 / Chapter 2.1.4 --- Numerical Results --- p.9 / Chapter 2.1.5 --- Discussion and Conclusion --- p.14 / Chapter 2.2 --- Non-Linear Couplings --- p.14 / Chapter 2.2.1 --- Model and Formalism --- p.14 / Chapter 2.2.2 --- Gradient in Coupling Constant --- p.16 / Chapter 2.2.3 --- Gradient in Moment of Inertia --- p.16 / Chapter 2.2.4 --- Numerical Results --- p.17 / Chapter 2.2.5 --- Discussion and Conclusion --- p.29 / Chapter 3 --- Torsional Motion of Rotating Particles with graded potential --- p.30 / Chapter 3.1 --- Linear Interaction --- p.30 / Chapter 3.1.1 --- Model and Formalism --- p.30 / Chapter 3.1.2 --- Gradient in On-site Torsional Potential --- p.32 / Chapter 3.1.3 --- Numerical Results --- p.33 / Chapter 3.1.4 --- Discussion and Conclusion --- p.43 / Chapter 3.2 --- Non-linear Interaction --- p.43 / Chapter 3.2.1 --- Model and Formalism --- p.43 / Chapter 3.2.2 --- Numerical Results --- p.45 / Chapter 3.2.3 --- Chaotic Effect --- p.62 / Chapter 3.2.4 --- Discussion and Conclusion --- p.64 / Chapter 4 --- Conclusion --- p.65 / Bibliography --- p.66

Controlling fields and properties has attracted ever increasing interest over past decades due to the rapid advancement of nanofabrication techniques. In the field of nano-optics, to overcome the limit of signal processing speed and device scale of traditional electronic devices, optical devices using photon as the signal carriers have been chosen as the potential candidates. However, the diffraction limit of light has limited the integration of the micro-meter photonic components into electronic chips. Plasmonics offer the possibility to control electromagnetic fields at the subwavelength scale. Moreover , this controlling become tunable by introducing gradient into the material and/or structure, i.e., taking the concept of functionally graded materials (FGM) to design materials. / Gradon confinements in graded materials and/or systems open a door for tunable fields-controlling, which have potential applications in a variety of fields. Our research methods and results provide an effective way to understand field localization in a variety of systems, and they can be applied to design and manufacture thermal devices and even on-chip plasmonic-optical devices. / Gradon confinements, or referred as frequency-controlled localization of fields are investigated in various graded plasmonic lattices. The correspondences between gradon confinements and Bloch oscillations as well as nonBloch oscillations are explored. By taking into account retardation and loss effects, the asymmetric localization behavior and broadband localizat ion due to graded host permittivity are studied. / This thesis will concentrate on gradon confinements, which make controlling fields and properties tunable in graded materials and/or systems. We start with investigating gradon modes and their properties in graded elastic lattices. Using the quantum-classical analogue method, the analytic envelope function is obtained and can be used to analyze the system-size dependence of inverse participation ratio of gradon modes. In damping graded elastic lattices , the frequency-dependent behavior of relaxation rate are studied analytically and numerically. / We continue to study the three-dimensional graded plasmonic lattices with fully retarded electromagnetic interactions. A generalized Ewald-Kornfeld summation formula is developed to deal with the long-range interaction. In the quasistatic limit, various plasmonic gradon modes are investigated. Taking retardation and loss into account, field localization and enhancement are calculated in three-dimensional graded plasmonic lattices with graded size, spacing, and/or host permittivity in one direction. / Zheng, Mingjie = 弹性和等离子体梯度子禁闭研究 / 郑明杰. / Adviser: Kin Wah Yu. / Source: Dissertation Abstracts International, Volume: 72-11, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 117-124) and index. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Zheng, Mingjie = Tan xing he deng li zi ti ti du zi jin bi yan jiu / Zheng Mingjie.

In this thesis, we will discuss the possibility of wave manipulation by graded materials and/or systems. In contrast to the traditional inhomogeneous media, i.e. periodically modulated system and randomly disordered system, graded system demonstrates a unique way to control wave, resulting in a new type of localization-delocalization transition, which can confine the primary excitations (e.g., photons, phonons, and surface plasmons) and redistribute them spatially. This is not only of fundamental significance, but will also pave new avenue for various applications, for example, in surface elastic waves, nanooptics, and plasmonics. It also has implications with practical problems in industry such as oil probing and earthquake study. / Manipulating waves (e.g., elastic or electromagnetic) inside nanostructures has attracted ever increasing interest over the past decades due to the rapid advancement of nanofabrication techniques. Particularly, interactions of light with structures modulated at the wavelength or subwavelength scale offer an opportunity to achieve novel properties and designated functionalities in nanophotonics. Notable examples include photonic crystals, various metamaterials, and plasmonic devices. / Moreover, we consider to combine the novel properties of gradons and surface plasmons (SPs), in an attempt to explore new mechanisms to manipulate SP. Firstly, we study an incrementally-spaced nanoparticle chain waveguide, in which coupled plasmon waves show a localization-delocalization transition, in analogy to the elastic gradons. Secondly, we propose waveguides using periodic plasmonic chains immersed in a graded host which can sustain "light", "heavy", and "light-heavy" plasmonic gradons. Existence of tunable passband is demonstrated in these systems. / Thus, in view of the success, we discuss many potential applications in plasmonics, such as junctions, transistors, and even on-chip integrated plasmonic-dielectric devices. In this regard, we further study the most commonly used coplanar photonic elements, i.e., ring resonators and their integrated devices. To explore the interactions between various gradons and typical excitations would be very interesting and rewarding. Our findings have important ramifications for understanding excitations with transition spectra in many condensed matter systems, ranging from ultrasonic waves, seismic waves to light waves, microwaves, as well as quantum waves. / We started with one-dimensional graded networks of coupled harmonic oscillators. By examining the vibrational mode characteristics, we have identified a new kind of vibrational excitations, which are named "gradons". The features of elastic gradon are elab orated. Gradon localization is also different from well-known mechanisms of localization transition, such as defect(s) and Anderson-type localization. Gradons in higher dimensional graded elastic networks show more intriguing behaviors; we proved the existence of "soft", "hard", and "soft-hard" gradons in two dimensional cases. / Xiao Junjun = 新型调波功能材料 : 梯度子及其在纳米光学中的应用 / 肖君军. / "May 2006." / Adviser: Kin Wah Yu. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1694. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 108-118). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307. / Xiao Junjun = Xin xing diao bo gong neng cai liao : ti du zi ji qi zai na mi guang xue zhong de ying yong / Xiao Junjun.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: Patrick S. Nicholson. Includes bibliographical references (leaves 162-181). Also available online.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2006. / Includes bibliographical references (leaves 178-191).

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Thesis (M.S. in M.S.E.)--School of Materials Science and Engineering, Georgia Institute of Technology, 2004. Directed by Rober Narayan. / Includes bibliographical references (leaves 85-92).