Дисертації з теми "Nanophotonic devices"
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Yu, Renwen. "Toward next-generation nanophotonic devices." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667314.
Повний текст джерелаEn esta tesis, pretendemos explorar varios diseños novedosos de nanoestructuras basadas en grafeno, con diversas funcionalidades. Tras presentar brevemente los conceptos fundamentales y los modelos teóricos utilizados en esta tesis en el Capítulo 1, en el Capítulo 2 mostramos la posibilidad de describir la respuesta de nanopartículas plasmónicas (incluyendo efectos de retardo) mediante métodos de simulación semi-analíticos sencillos y sin la necesidad de emplear grandes recursos computacionales. Posteriormente, empleamos estos modelos en el desarrollo de un primer tipo de dispositivo: moduladores ópticos. Añadiendo láminas de grafeno acopladas a diferentes tipos de resonadores ópticos, podemos mejorar la intensidad de la luz en el plano del grafeno, y por lo tanto también su nivel de absorción, la cual puede ser modulada a voluntad mediante el nivel de dopado electrostático del grafeno, como se explora en el Capítulo 3. Los modelos empleados predicen cambios en la transmisión del orden de la unidad, produciendo así la absorción total por parte del dispositivo de la luz incidente. En esta clase de dispositivos, así como en todos los dispositivos nanofotónicos, la producción de calor mediante la absorción de la luz puede degradar severamente su rendimiento, así como limitar su vida útil, lo que hace que la manipulación de la fuente y el flujo de calor en la nanoescala sea una componente crucial del desarrollo. En el Capítulo 4, empleamos las extraordinarias propiedades ópticas y térmicas del grafeno para mostrar que puede tener lugar una transferencia ultrarrápida de calor radiativo entre nanoestructuras vecinas, facilitada por los plasmones del grafeno, los cuales a su vez experimentan efectos fototérmicos asociados con este proceso de disipación. Nuestros hallazgos revelan un nuevo régimen para la energía térmica a nanoescala, en la que la transferencia de calor radiativa se convierte en el mecanismo principal de disipación de calor. Además de los daños causados por la deposición de calor, la energía térmica generada puede ser de hecho usada como herramienta para la fotodetección: tal es el caso, por ejemplo, de los bolómetros de silicona, empleados para la fotodetección por infrarrojos. En el Capítulo 5, mostramos que la excitación de un solo plasmón en una unión de grafeno altera radicalmente sus propiedades eléctricas debido al calentamiento óptico. Este hecho puede ser empleado para demostrar el funcionamiento eficaz de un fotodetector en la región media de los infrarrojos a temperatura ambiente, tanto a través de predicciones teóricas como su corroboración experimental (en colaboración con el grupo del Prof. Fengnian Xia de la Universidad de Yale). Finalmente, en el Capítulo 6, mostramos a través de simulaciones mecánico-cuánticas (introducidas en el Capítulo 1), que tanto la respuesta óptica lineal como la no lineal de las nanoestructuras de grafeno pueden ser dramáticamente alteradas por la presencia de una sola molécula vecina que transporte o bien una carga elemental o un dipolo permanente. En base a estos resultados, afirmamos que las estructuras de grafeno nanoscópicas podrían ser una plataforma eficiente para detectar moléculas portadoras de carga o dipolos.
Heucke, Stephan F. "Advancing nanophotonic devices for biomolecular analysis." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-165294.
Повний текст джерелаGarner, Brett William. "Multifunctional Organic-Inorganic Hybrid Nanophotonic Devices." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc6108/.
Повний текст джерелаGarner, Brett William Neogi Arup. "Multifunctional organic-inorganic hybrid nanophotonic devices." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-6108.
Повний текст джерелаJohn, Jimmy. "VO2 nanostructures for dynamically tunable nanophotonic devices." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI044.
Повний текст джерелаInformation has become the most valuable commodity in the world. This drive to the new information age has been propelled by the ability to transmit information faster, at the speed of light. This erupted the need for finer researches on controlling the information carriers more efficiently. With the advancement in this sector, majority of the current technology for controlling the light, face certain roadblocks like size, power consumption and are built to be passive or are restrained technologically to be less active (Si- backed technology). Even though nothing travels faster than light, the real speed at which information can be carried by light is the speed at which we can modulate or control it. My task in this thesis aimed at investigating the potential of VO2, a phase change material, for nano-photonics, with a specific emphasis on how to circumvent the drawbacks of the material and to design and demonstrate efficient integrated devices for efficient manipulation of light both in telecommunication and visible spectrum. In addition to that we experimentally demonstrate the multipolar resonances supported by VO2 nanocrystals (NCs) can be dynamically tuned and switched leveraging phase change property of VO2. And thus achieving the target tailoring of intrinsic property based on Mie formalism by reducing the dimensions of VO2 structures comparable to the wavelength of operation, creating a scope for user defined tunable metamaterial
Deng, Sunan. "Nanophotonic devices based on graphene and carbon nanotubes." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/7041/.
Повний текст джерелаDahal, Rajendra Prasad. "Fabrication and characterization of III-nitride nanophotonic devices." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2198.
Повний текст джерелаNaughton, Jeffrey R. "Neuroelectronic and Nanophotonic Devices Based on Nanocoaxial Arrays." Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:108037.
Повний текст джерелаThesis advisor: Michael J. Burns
Recent progress in the study of the brain has been greatly facilitated by the development of new measurement tools capable of minimally-invasive, robust coupling to neuronal assemblies. Two prominent examples are the microelectrode array, which enables electrical signals from large numbers of neurons to be detected and spatiotemporally correlated, and optogenetics, which enables the electrical activity of cells to be controlled with light. In the former case, high spatial density is desirable but, as electrode arrays evolve toward higher density and thus smaller pitch, electrical crosstalk increases. In the latter, finer control over light input is desirable, to enable improved studies of neuroelectronic pathways emanating from specific cell stimulation. Herein, we introduce a coaxial electrode architecture that is uniquely suited to address these issues, as it can simultaneously be utilized as an optical waveguide and a shielded electrode in dense arrays
Thesis (PhD) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
Mangelinckx, Glenn. "Investigation of nanophotonic devices based on transformation optics : Transforming reflective optical devices." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-42442.
Повний текст джерелаKoos, Christian. "Nanophotonic devices for linear and nonlinear optical signal processing." Karlsruhe : Univ.-Verl. Karlsruhe, 2007. http://d-nb.info/987044451/34.
Повний текст джерелаOng, Jun Rong. "Linear and Nonlinear Photonics Using Resonant Silicon Nanophotonic Devices." Thesis, University of California, San Diego, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3639204.
Повний текст джерелаResonant devices are an integral component of the integrated silicon photonics platform, with applications in filters, switches, modulators, delays, sensors etc. High index contrast SOI waveguides can be used to form compact micro-ring resonators with bend radii on the order of micro-meters. This work describes the application of micro-ring resonators in linear and nonlinear silicon photonics. We describe the use of higher-order coupled resonators for use as ultra-high contrast pass-band filters with close to 100 dB extinction. Using the spontaneous four-wave mixing process, a third-order nonlinear Kerr effect, coupled resonator waveguides are shown to be a useful source of heralded single photons, as well as other unique quantum states of light. We also describe four-wave mixing results in silicon micro-resonators, where nonlinear loss effects are mitigated by reverse biased p-i-n diodes, showing potential for high-speed optical signal processing.
Li, Luozhou. "Diamond nanophotonic devices for quantum information processing and sensing." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101573.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 107-123).
The nitrogen vacancy (NV) center in diamond has in recent years emerged as a promising solid state system for quantum information processing and sensing applications. However, using NV centers to build up quantum networks for these applications faces several challenges, such as the lack of efficient interface between NVs and photons, difficulty of maintaining spin coherence times, and scalable techniques for fabrication of NV-photon networks. This thesis focuses on overcoming these challenges by fabricating diamond devices to improve the collection efficiency of NV photon emission, especially from the zero phonon line (ZPL), while maintaining long spin coherence times after fabrication. After an introduction to the subject matter in Chapter 1, Chapter 2 discusses a fabrication technique to produce vertical membranes out of bulk diamond plates. This work showed that after reactive ion etching, the spin properties of isolated NVs in diamond nanostructures were largely preserved. We also observed increased photoluminescence collection from shallow implanted NV centers in these slabs. In Chapter 3, we describe a versatile nanofabrication method based on re-usable silicon membrane hard masks, patterned using standard lithography and mature silicon processing technology. These masks are transferred precisely onto targeted regions of diamond membranes, where photonic devices can be realized without the need for spin coating, wet etching or electron beam exposure. Chapter 4 describes and demonstrates an alternative technique for fabricating one-dimensional photonic crystal (PC) cavities in single-crystal diamond by a combination of reactive ion etching (RIE) and focused ion beam milling. We compare it to transferred silicon hard mask lithography with RIE. Chapter 5 demonstrate NV-nanocavity systems in the strong Purcell regime with consistently high Q factors while preserving the long spin coherence times of NVs. These systems enable coherent spin control of cavity-coupled semiconductor qubits with coherence times exceeding 200 [mu]s - an increase by two orders of magnitude over previously reported optical cavity-coupled solid-state qubits. Chapter 6 introduces a circular diamond "bullseye" grating that achieves the highest reported photon collection rate from a single NV center of 4.56 0.08 Mcps at saturation when fitted with the widely-used background counts subtraction method. We also quantified the emission by a g(²)-corrected saturation curve measurement which gives a rigorous single photon count rate of 2.7 ± 0.09 Mcps. By using dynamical decoupling sequences, we measured a spin coherence time of 1.7 ± 0.1 ms, which is comparable to the highest reported spin coherence times of NVs under ambient conditions and also indicates that the bullseye fabrication process does not degrade the spin properties noticeably. The planar architecture allows for on-chip integration, and the circular symmetry supports left- and right-handed circularly polarized light for spin-photon entanglement. In Chapter 7, we demonstrate a top-down fabrication process using a porous metal mask and a self-guiding RIE process that enables rapid nanocrystal creation across the entirety of a high-quality chemical vapor deposited (CVD) diamond substrate. High-purity CVD nanocrystals produced in this manner exhibit single NV phase coherence times reaching 210 ps and magnetic field sensitivities of 290 nT.Hz⁻¹/² without compromising the spatial resolution of a nanoscale probe.
by Luozhou Li.
Ph. D.
Rajasekharan, Unnithan Ranjith. "Nanophotonic devices based on carbon nanotubes and liquid crystals." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609672.
Повний текст джерелаVemuri, Padma Rekha. "Surface Plasmon Based Nanophotonic Optical Emitters." Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc5584/.
Повний текст джерелаLin, Chunchen. "Semiconductor-based nanophotonic and terahertz devices for integrated circuits applications." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 7.48 Mb., 180 p, 2006. http://wwwlib.umi.com/dissertations/fullcit/3221130.
Повний текст джерелаGholipour, Behrad. "Novel chalcogenide optoelectronic and nanophotonic information storage and processing devices." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/341256/.
Повний текст джерелаBhattacharya, Indrasen. "Nanophotonic Devices Based on Indium Phosphide Nanopillars Grown Directly on Silicon." Thesis, University of California, Berkeley, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10685771.
Повний текст джерелаIII-V optoelectronic device integration in a CMOS post-process compatible manner is important for the intimate integration of silicon-based electronic and photonic integrated circuits. The low temperature, self-catalyzed growth of high crystalline quality Wurtzite-phase InP nanopillars directly on silicon presents a viable approach to integrate high performance nano-optoelectronic devices.
For the optical transmitter side of the photonic link, InGaAs quantum wells have been grown in a core-shell manner within InP nanopillars. Position-controlled growth with varying pitch is used to systematically control emission wavelength across the same growth substrate. These nanopillars have been fabricated into electrically-injected quantum well in nanopillar LEDs operating within the silicon transparent 1400–1550 nm spectral window and efficiently emitting micro-watts of power. A high quality factor (Q ~ 1000) undercut cavity quantum well nanolaser is demonstrated, operating in the silicon-transparent wavelength range up to room temperature under optical excitation.
We also demonstrate an InP nanopillar phototransistor as a sensitive, low-capacitance photoreceiver for the energy-efficient operation of a complete optical link. Efficient absorption in a compact single nanopillar InP photo-BJT leads to a simultaneously high responsivity of 9.5 A/W and high 3dB-bandwidth of 7 GHz.
For photovoltaic energy harvesting, a sparsely packed InP nanopillar array can absorb ~90% of the incident light because of the large absorption cross section of these near-wavelength nanopillars. Experimental data based on wavelength and angle resolved integrating sphere measurements will be presented to discuss the nearly omnidirectional absorption properties of these nanopillar arrays.
Chamanzar, Maysamreza. "Hybrid nanoplasmonic-nanophotonic devices for on-chip biochemical sensing and spectroscopy." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50145.
Повний текст джерелаBabinec, Thomas Michael. "Topics in Nanophotonic Devices for Nitrogen-Vacancy Color Centers in Diamond." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10461.
Повний текст джерелаEngineering and Applied Sciences
Barth, Michael. "Hybrid nanophotonic elements and sensing devices based on photonic crystal structures." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16155.
Повний текст джерелаThis thesis deals with the development and investigation of novel photonic crystal structures for applications in nanophotonics and optofluidics. Thereby, a first series of experiments focuses on the characterization and optimization of photonic crystal cavities in the visible wavelength range, demonstrating unprecedented cavity quality factors of up to 3400. These structures are subsequently employed as platforms for the creation of advanced hybrid nanophotonic elements by coupling external particles (such as diamond nanocrystals and metal nanoparticles) to the cavities in a well-controlled manner. For this purpose, a nanomanipulation method is developed, utilizing scanning probes for the deterministic positioning and assembly of particles on the photonic crystal structures. Various types of such hybrid elements are realized and investigated, including diamond-coupled cavities, plasmon-coupled cavities, and metal-diamond hybrid structures. Apart from applications in nanophotonics, different types of photonic crystal structures are also studied with regard to their performance as biochemical sensing elements. For the first time a thorough numerical analysis of the optical forces exerted on objects in the near-field of photonic crystal cavities is conducted, providing novel means to trap, detect, and investigate biological particles in integrated optofluidic devices. Furthermore, various types of photonic crystal fibers are studied with regard to their detection sensitivity in absorption and fluorescence measurements, revealing a clear superiority of selectively infiltrated hollow-core designs in comparison to solid-core fibers.
Ung, Thi phuong lien. "Control disorder for electromagnetic localization in plasmonic devices for nanophotonic application." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV013/document.
Повний текст джерелаMetallic nanostructures allow to confine light at subwavelength scales by the excitation of surface plasmon. They open the way for many applications in imaging, photonic components development and quantum information. This thesis deals with the study of metallic nanostructures, semi-continuous or based on holes gratings with a controlled disorder, and their interaction with colloidal semiconductor nanocrystals that are very photostable. Combining several complementary experimental approaches (far-field spectroscopy, near-field optical microscopy, near-field active probe microscopy, characterization by confocal microscopy of the emission of nanocrystals coupled to the metallic surfaces), we were able to highlight specific characteristics of the plasmon modes of these different structures. For the gratings with a controlled disorder, we have in particular analyzed the emergence of intense localized modes and determined the influence of parameters such as the thickness of the gold layer, the diameter of the holes or the initial periodicity of the grating. The experimental results are in very good agreement with the numerical simulations carried out by FDTD
Koos, Christian [Verfasser]. "Nanophotonic devices for linear and nonlinear optical signal processing / von Christian Koos." Karlsruhe : Univ.-Verl. Karlsruhe, 2007. http://d-nb.info/987044451/34.
Повний текст джерелаArca, Ahmet. "The design and optimisation of nanophotonic devices using the Finite Element Method." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11169/.
Повний текст джерелаSodagar, Majid. "Enabling integrated nanophotonic devices in hybrid cmos-compatible material platforms for optical interconnection." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53952.
Повний текст джерелаSoltani, Mohammad. "Novel integrated silicon nanophotonic structures using ultra-high Q resonators." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31647.
Повний текст джерелаCommittee Chair: Prof. Ali Adibi; Committee Member: Prof. Joseph Perry; Committee Member: Prof. Stephen Ralph; Committee Member: Prof. Thomas Gaylord. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Ghoshal, Amitabh. "Plasmon enhanced near-field interactions in surface coupled nanoparticle arrays for integrated nanophotonic devices." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4630.
Повний текст джерелаID: 028917015; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references (p. 111-119).
Ph.D.
Doctorate
Optics and Photonics
Natarajan, Aswani. "Electromagnetic modelling of graphene-based nanophotonic devices : modal and scattering approaches using the finite element method." Thesis, Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0472.
Повний текст джерелаPlasmonics based on 2D materials is a burgeoning field in photonics with potential groundbreaking technological implications for diagnostics, energy and data communication. Graphene, a unique 2D material with excellent plasmonic properties is a promising alternative to conventional noble metals in plasmonics notably due to its tunable properties. Graphene is modelled in this thesis as an infinitesimally thin current-carrying sheet in a fully vectorial finite element Galerkin framework as opposed to more conventional models where graphene is considered to be of finite thickness. A rigorous study of the behaviour of the electromagnetic field along the propagation direction in an openridge waveguide is carried out by modelling graphene as a 1D conductive scatterer which acts as a local perturbation. The scattering model is verified through a full energy balance in different geometries. The large momentum mismatch that exists between the waveguide mode and the graphene plasmon mode in a graphene-based waveguide severely alters the coupling between these two modes. To overcome this, a coupler is designed using the developed scattering field formalism. Elaborate studies of the beating phenomenon observed in the coupler are performed. The designed waveguide coupler is apt for graphene of lengths equal to or shorter than the order of the wavelength. Several studies involving the various diffraction orders of the grating coupler, waveguide thickness, etc. are conducted. The parameters of the coupler are then optimized to yield a compact and integrated graphene-based grating coupler of efficiency as high as 80% in the infrared region
Heucke, Stephan F. Verfasser], and Hermann E. [Akademischer Betreuer] [Gaub. "Advancing nanophotonic devices for biomolecular analysis : force spectroscopy and nanopositioning of single molecules in zero-mode waveguides / Stephan F. Heucke. Betreuer: Hermann Gaub." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1046785311/34.
Повний текст джерелаTaverne, Mike. "Modelling and fabrication of nanophotonics devices." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715771.
Повний текст джерелаGeng, Wei. "Coupling nanostructures towards integrated nanophotonics devices." Thesis, Troyes, 2015. http://www.theses.fr/2015TROY0016/document.
Повний текст джерелаWith the significant advantages in storing, processing and transmitting information, quantuminformation science has attracted abundant studies in the last few decades, by which many proofs ofprinciple have been made using macro-photonic experimental techniques. However, the applicabilityof this technology still strongly depends on the miniaturization of the system, i.e. the on-chip integration of quantum photonic functionalities. The general prerequisites of an integrated quantumchip are localised and efficient generation, transportation and detection of photons. Some effortshave been made successfully involving one or two necessary features. However, the full integration still remains unaccomplished. Based on semiconductor nanophotonic elements and simple nanofabrication techniques, this thesis aims to provide a strategy for on-chip quantum photonic integration. An efficient and local excitation of a single photon source with a subwavelengthwaveguide is firstly demonstrated. Then we investigate the efficient light exchange betweennanostructures and waveguides that can serve as linking blocks between devices in an integrationsystem. The fabrication and characterisation of a sensitive photodetector based on a single nanowireis also presented, which exhibits great potential in single-photon detection. At the end, an outlook ofthe ultimate integration of all these functionalities is provided
Benedicto, Jessica. "Contribution à l'étude des propriétés optiques des métamatériaux hyperboliques." Thesis, Clermont-Ferrand 2, 2013. http://www.theses.fr/2013CLF22403/document.
Повний текст джерелаIn the early 80’s, planar or periodic photonics crystals have been introduced in order to control light and to obtain entirely new optical properties. The unrivalled properties of these metamaterials are of tremendous interest for advanced photonic systems, with some important applications such as materials with negative refraction or flat lenses. However, these structures present optical losses induced by metals defects and experimental fabrication at nanometric scales that prevent them to reach the expected performances. A new approach based on describing metallo-dielectric as anisotropic materials has then been proposed as an alternative description. In parallel, the limits of the Drude model have been experimentally highligthed. In this context this manuscript presents a theoretical and numerical study of metallo-dielectric multilayers that can be considered as homogeneous media with a hyperbolic dispersion relation. We first present the link between negative refraction and large negative lateral shifts, and then focus on the design of flat lenses with subwavelength resolution : structures allowing a better resolution than the classical diffraction limit. We thus developed a theory based on the approximation of the hyperbolic medium, by a homogeneous and isotropic medium with a parabolic development of the vector of wave of Bloch. Finally, the tools required to study the influence of the intrinsic nonlocality of metals on the optical properties of multilayers are developped and the formalism is applied to metallo-dielectric lenses
Zhao, Songrui. "Molecular beam epitaxial growth, characterization, and nanophotonic device applications of InN nanowires on Si platform." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117217.
Повний текст джерелаLes nanofils semi-conducteurs sans dislocations sont une voie très prometteuse vers l'intégration des semi-conducteurs composés avec la technologie silicium. Cependant, un contrôle précis de dopage des nanofils, ainsi que les propriétés de charge de surface, reste un défi universel à ce jour. À cet égard, nous avons étudié la croissance épitaxiale par faisceau moléculaire et les propriétés de surface corrélés électriques et optiques des nanofils de InN sur du substrat de silicium, qui ont émergé comme candidat prometteur pour l'avenir des dispositifs électroniques et photoniques à très haute vitesse et à échelle nanométriques.Pour la première fois, en améliorant le processus de croissance épitaxiale, InN intrinsèque est atteint, à la fois dans le volume et sur les surfaces non polaires de InN. Le niveau de Fermi à la surface est mesuré et localisée sous le CBM, ce qui suggère l'absence d'accumulation d'électrons en surface. Ces nanofils InN intrinsèques possédent une concentration de porteurs libres très faible ~1e13 /cm3, ainsi que d'une mobilité proche de le théoriquement prédite d'électrons entre 8000 à 12000 cm2/V·s à température ambiante. Ce résultat est en contraste direct avec les 2DEG observés sur les surfaces d'InN. En outre, les propriétés de charge de surface de nanofils InN, y compris la formation de 2DEG et les caractéristiques d'émission optiques, peut être réglé avec précision, pour la première fois, par l'intermédiaire du contrôle d'incorporation de dopants de type n.Plus important encore, dopage de type p dans les nanofils InN est également réalisé pour la première fois. La présence de niveaux d'énergie Mg-accepteur est démontrée par les spectres de PL. Dans ces nanofils dopés de Mg, il n'y a pas d'accumulation d'électrons de surface et le niveau de Fermi dans le volume est proche de la VBM, ce qui indique un matériau de type p.En fin, la jonction p-i-n basé sur des nanofils InN photodétecteurs qui peut être utilisé en mode photovoltaïque est démontrée, avec une réponse à la lumière jusqu'à la longueur d'onde des télécommunications à de basses températures. Ce travail de thèse fournit un exemple frappant, ainsi que prépare le terrain pour le développement "matériaux par conception" de la technologie des dispositifs en silicium intégrée à base InN à l'échelle nanométrique.
Ramirez, Priego Patricia. "Low-cost point-of-care biosensor device for clinical diagnosis in developing countries." Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/671902.
Повний текст джерелаActualmente el diagnóstico de Tuberculosis (TB) se realiza en laboratorios centralizados, empleando equipos voluminosos, reactivos complejos y personal capacitado, aumentando los costes y el tiempo para obtener los resultados. Por esta razón, el objetivo de esta Tesis Doctoral es el desarrollo de una plataforma point-of-care (POC) capaz de ofrecer una respuesta rápida y fiable en el diagnóstico de TB. Para llevar a cabo este objetivo, la plataforma POC integra un novedoso sensor fotónico incorporado en un cartucho de micofluídica desechable. El sensor fotónico consiste en un conjunto de interferómetros Mach-Zehnder que ofrecen una alta sensibilidad. En primer lugar, se llevó a cabo una caracterización óptica para estudiar el rendimiento de la plataforma POC y su capacidad para ser empleada en aplicaciones biosensoras. Una vez caracterizada ópticamente, se evaluaron distintas estrategias de biofuncionalización para incorporar anticuerpos específicos como bioreceptores a la superficie del sensor. Después de un estudio en profundidad, se seleccionó y empleó la estrategia de biofuncionalización óptima para el análisis de los biomarcadores de TB. Los biomarcadores de TB se evaluaron tanto en solución tampón como en muestras biológicas, particularmente en orina humana. El biomarcador más prometedor y conocido de TB es el lipoarabinomanano (LAM), un componente de la pared celular bacteriana. En concreto, la detección de este biomarcador fue validada con muestras clínicas de pacientes con TB y donantes sanos, mostrando la capacidad de nuestra plataforma POC para discriminar a aquellos pacientes con Tuberculosis activa. Además, el diseño del sensor fotónico permite la detección simultánea de seis biomarcadores distintos. Teniendo esto en cuenta, hemos llevado a cabo una prueba de concepto del empleo de la plataforma biosensora POC para la detección de un panel de biomarcadores de TB utilizando nanolitografía Dip-Pen para la deposición de cada bioreceptor en cada sensor. Nuestros resultados, validados en estudios clínicos más amplios, podrían tener importantes implicaciones diagnósticas. Además, nuestro biosensor POC ofrece una serie de ventajas en comparación con los métodos recomendados por la Organización Mundial de la Salud.
Nowadays, Tuberculosis (TB) diagnosis is carried out at centralised laboratories, employing bulky equipment, complex reagents, and trained staff, increasing costs and the time to obtain the results. For that reason, the aim of this Doctoral Thesis is to develop a point-of-care (POC) platform able to deliver a prompt and reliable response to TB diagnosis, taking advantage of a highly sensitive evanescent wave optical sensor. The POC platform integrates a novel photonic sensor consisting of a Mach-Zehnder Interferometer transducer array incorporated in a disposable microfluidic cartridge. Firstly, an optical characterisation was carried out to study the new POC performance and its ability to be employed for biosensing applications. Once the POC platform was optically characterised, diverse biofunctionalisation strategies were tested in order to incorporate specific antibodies as bioreceptors to the sensor surface. After an in-depth study, the optimal biofunctionalisation strategy was selected and employed for the analysis of the TB biomarkers. The TB biomarkers were evaluated in both buffer and biological samples, particularly human urine. The most promising and well-known TB biomarker was lipoarabinomannan (LAM), a bacterial cell wall component. In particular, this biomarker detection was validated with clinical samples from TB patients and healthy donors, showing the ability of our POC platform to discriminate those patients with active TB. Moreover, taking advantage of the photonic sensor design, which allows the simultaneous detection of six different biomarkers, we initiated the proof-of-concept of the POC platform for a TB biomarker panel detection using Dip-Pen Nanolithography for each corresponding bioreceptor deposition. Our results, if validated with larger clinical studies, could have important diagnostic implications taking into account the advantages added by our POC biosensor in comparison with the methods recommended by the World Health Organisation.
Universitat Autònoma de Barcelona. Programa de Doctorat en Biotecnologia
Rodríguez, Fortuño Francisco José. "Design and implementation of plasmonic metamaterials and devices." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/31207.
Повний текст джерелаRodríguez Fortuño, FJ. (2013). Design and implementation of plasmonic metamaterials and devices [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31207
TESIS
Premiado
Tellez, Limon Ricardo. "Light propagation in integrated chains of metallic nanowires : towards a nano-sensing device." Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0039/document.
Повний текст джерелаLocalized surface plasmons (LSP) are used to control and concentrate the electromagnetic field in small volumes of matter. This is a very interesting property in the context of biophotonics. Indeed, it allows an enhancement of the light-matter interaction at the cell scale, or even at a single molecule scale. The technological challenge is to propose optical devices able to efficiently couple light into localized plasmonic modes and to improve the detection of signals resulting from the interaction between the confined light and the analyte under detection.In this thesis work, we theoretically and experimentally study the guiding and confinement properties of light in periodic arrays of metallic nanowires of rectangular and triangular (nanocones) cross section that support localized plasmons. These nanowires are integrated in a photonic circuit that enables an efficient light coupling. The extinction spectra of the plasmonic resonances are directly obtained by analyzing the transmitted light in the device. By making use of the Fourier modal method, we perform an exhaustive theoretical study of the plasmonic Bloch modes that propagate due to the near-field coupling of the localized plasmons resonances. It is demonstrated that for the metallic nanocones, the optical field can be strongly enhanced by a controllable tip effect and remarkably intense
Prasad, Rohit. "Device integration of the CoBiSS spectrometer and modelisation of (L)SPR chip for the detection through CoBiSS." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0031.
Повний текст джерелаAs the world is moving towards Internet of Things, an optical detection device is presented that can be utilized in this domain. This device can be used to do tests that use optical detection for analysis like monitoring of Health of a person by doing a blood test or other medical analysis and also be used to monitor environment by testing water or air in cities, mountains, factories, rivers and so on for a practical purpose. To create this optical detection device, a combination of spectrometer named Coupled Bi-Directional Sampling Spectrometer (CoBiSS) [Patent number WO2009127794A1] and Surface Plasmon Resonance (SPR) Chip has been used. For the optical integration, a new analysis of the sampling in the spectrometer CoBiSS is presented. Followed by, Device and Optical Integration of CoBiSS has been done to remove all the moving parts. It was necessary to make the device small that can be handheld and portable. For ease of use a Graphical User interface was developed. For detection, CoBiSS was added with a chip of SPR. A modelisation of SPR chip was done to maximize its sensitivity. A new Localized Surface Plasmon Resonance (LSPR) chip has been proposed to work with CoBiSS. Optimization of LSPR chip has been performed to maximize the sensitivity. A new definition for the calculation of Sensitivity has been proposed. This device needs the addition of functionalization on (L)SPR Chip for detection and a final application. This device could be an ideal “Thing” in Internet of Things
Gaignebet, Nicolas. "Réalisation et caractérisation de puces de capteurs à cristaux photoniques : Vers un dispositif de biodétection intégré." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI128.
Повний текст джерелаThe needs for portable molecular analysis tools are growing, including in the fields of emergency care, early medical diagnosis, or food safety analysis. These needs lead to the development of performant biosensors, meeting the criteria of “Point-of-Care” (POC), that is, the detection in the field, whether at the patient’s place, the physician’s office, etc. POC sensors’ primary missions are to reduce the analysis time and cost, to allow for a quicker therapeutic decision. In addition, thanks to their portability, they can provide analysis availability in remote areas, far from hospitals or medical laboratories. The objective of this PhD work is to develop an optical sensing system, compatible with the POC criteria, and addressing the needs in terms of molecular screening. To meet these criteria, this sensing system should be portable, fast, low-cost, and able to detect multiple biomolecules in parallel on a disposable chip, while providing good sensing performances. The approach presented in this manuscript consists in a lens-less imaging system, exploiting photonic crystals on a silicon chip, with a normal incidence illumination by a low-cost light source. The main results of this PhD work are on one hand the demonstration of a specific detection of biomolecules, thanks to our photonic crystal sensors; and on the other hand the demonstration of the integration of an on-chip spectrometry functionality using photonic crystals, towards an application in lens-less imaging detection compatible with the POC criteria
Sharma, Yashna. "Nanophotonic sensors and devices." Thesis, 2017. http://localhost:8080/xmlui/handle/12345678/7336.
Повний текст джерелаDi, Meo Valentina, Felice Crupi, Giuseppe Cocorullo, Ivo Rendina, and Emanuela Esposito. "Integration of nanophotonic devices on silicon." Thesis, 2019. http://hdl.handle.net/10955/1712.
Повний текст джерелаThe purpose of this thesis research project has been the integration of photonic nanostructures on silicon substrate. In particular, three different devices have been developed, whose application fields fall within the main research topics of silicon photonics. Indeed, a plasmonic biochemical sensor, an all-dielectric metamaterial for all-optical switching applications and a 1D photonic crystal as an interconnecting device have been successfully integrated on silicon substrate. All of the proposed devices could lead to noticeable advances in silicon photonics, thanks to their potentiality for the development of integrated silicon-based nanodevices.
University of Calabria
Lin, Ronghui. "Design and topological optimization of nanophotonic devices." Diss., 2020. http://hdl.handle.net/10754/665997.
Повний текст джерелаLončar, Marko. "Nanophotonic Devices Based on Planar Photonic Crystals." Thesis, 2003. https://thesis.library.caltech.edu/2372/1/thesis_loncar_whole.pdf.
Повний текст джерелаPhotonic Crystals, man-made periodic structures with a high refractive index contrast modulation, have recently become very interesting platform for the manipulation of light. The existence of a photonic bandgap, a frequency range in which propagation of light is prevented in all directions, makes photonic crystals very useful in applications where spatial localization of light is required. Ideally, by making a three-dimensional photonic crystal, propagation of light in all three dimensions can be controlled. Since fabrication of 3-D structures is still a difficult process, a more appealing approach is based on the use of lower dimensional photonic crystals. A concept that has recently attracted a lot of attention is a planar photonic crystal based on a dielectric membrane, suspended in the air, and perforated with a two-dimensional lattice of holes.
In this thesis theoretical and experimental study of planar photonic crystal nanolasers, waveguides and super-dispersive elements is presented. Room temperature operation of low-threshold nanolaser is demonstrated, both in air and in different chemical solutions. For the first time, we have demonstrated that photonic crystal nanocavity lasers can be used to perform spectroscopic tests on ultra-small volumes of analyte. Our porous cavity design permits the introduction of analyte directly into the high optical field of the laser cavity, and therefore it is ideally suited for the investigation of interaction between light and matter on a nanoscale level. We showed that small changes in refractive index of the ambient surrounding the laser can be detected by observing the shifts in emission wavelengths of the laser. Our lasers can be integrated into large arrays to permit the analysis of many reagents at the same time. The nanolasers can also be integrated with photonic crystal waveguides to form the integrated systems of higher complexities. Theoretical and experimental investigation of various photonic crystal waveguide designs is discussed. Details of the fabrication procedure used to realize nanophotonic devices in silicon on insulator as well as InGaAsP materials are presented.
Lin, Xiaohui active 21st century. "Novel printing technologies for nanophotonic and nanoelectronic devices." Thesis, 2013. http://hdl.handle.net/2152/26609.
Повний текст джерелаtext
Lin, Che-Yun. "Silicon integrated nanophotonic devices for on-chip optical interconnects." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-5720.
Повний текст джерелаtext
(9174383), Shaimaa I. Azzam. "Novel light trapping and nonlinear dynamics in nanophotonic devices." Thesis, 2020.
Знайти повний текст джерелаNumerous fundamental quests and technological advances require trapping light waves. Generally, light is trapped by the absence of radiation channels or by forbid- ding access to them. Unconventional bound states of light, called bound states in the continuum (BICs), have recently gained tremendous interest due to their peculiar and extreme capabilities of trapping light in open structures with access to radiation. A BIC is a localized state of an open structure with access to radiation channels, yet it remains highly confined with, in theory, infinite lifetime and quality factor. There have been many realizations of such exceptional states in dielectric systems without loss. However, realizing BICs in lossy systems such as those in plasmonics remains a challenge. This thesis explores the realization of BICs in a hybrid plasmonic-photonic structure consisting of a plasmonic grating coupled to a dielectric optical waveguide with diverging radiative quality factors. The plasmonic-photonic system supports two distinct groups of BICs: symmetry protected BICs and Friedrich-Wintgen BICs. The photonic waveguide modes are strongly coupled to the gap plasmons in the grating leading to an avoided crossing behavior with a high value of Rabi splitting of 150 meV . Additionally, it is shown that the strong coupling significantly alters the band diagram of the hybrid system, revealing opportunities for supporting stopped light at an off-Γ wide angular span.
In another study, we demonstrate the design of a BIC-based all-dielectric metasurface and its application as a nanolaser. Metasurfaces have received an ever-growing interest due to their unprecedented ability to control light using subwavelength structures arranged in an ultrathin planar profile. However, the spectral response of meta- surfaces is generally broad, limiting their use in applications requiring high quality (Q) factors. In this study, we design, fabricate, and optically characterize metasur- faces with very high Q-factors operating near the BIC regime. The metasurfaces are coated with an organic lasing dye as an active medium, and their lasing action is experimentally characterized. The proposed BIC-based metasurfaces nanolaser have very favorable characteristics including low threshold, easily tunable resonances, polarization-independent response, and room temperature operation.
The second part of the thesis deals with the nonlinear phenomenon in nanopho- tonic structures. We developed an advanced full-wave framework to model nonlinear light-matter interactions. Rate equations, describing atomic relaxations and excita- tion dynamics, are coupled to the Maxwell equations using a Lorentzian oscillator that models the kinetics-dependent light-matter interaction in the form of averaged polarization. The coupled equations are discretized in space and time using a finite- difference time-domain method that provides a versatile multiphysics framework for designing complex structures and integrating diverse material models. The proposed framework is used to study gain dynamics in silver nanohole array, reverse saturable absorption dynamic in optical limiters, and saturable absorption in random lasers. This framework provides critical insights into the design of photonic devices and their complementary optical characterization, and serve as an invaluable utility for guiding the development of synthetic materials. It allows accurate physics-based numerical modeling and optimization of the devices with complex micro- and nano-structured materials and complex illumination sources such as non-paraxial structured beams.
Chen, Charlton J. "Precision Tuning of Silicon Nanophotonic Devices through Post-Fabrication Processes." Thesis, 2011. https://doi.org/10.7916/D8MS40QG.
Повний текст джерелаKalaee, Mahmoud. "Superconducting Electromechanical and Nanophotonic Devices for Quantum Measurement and Conversion." Thesis, 2019. https://thesis.library.caltech.edu/11247/7/Kalaee_Mahmoud_Thesis.pdf.
Повний текст джерелаMicroscale and nanoscale mechanical resonators have been used in advanced technological applications, from high precision time keeping and mass sensing, to processing high frequency signals in mobile communications. In the last few decades, they have been an important part of progress in the field of quantum information and metrology and have been proposed as quantum memories or transducers for measuring or connecting different types of quantum systems.
The field of cavity optomechanics and electromechanics is concerned with coupling the electromagnetic field of a resonant optical cavity or electrical circuit to mechanical motion. These systems provide potential means to control and engineer the state of a mechanical object at the quantum level. This thesis contains the description of mechanical systems in megahertz to a few hundred megahertz frequency range formed by nano-fabricating photonic, phononic, and electrical circuits on a chip. These structures are designed to provide a large radiation pressure coupling between mechanical motion and electromagnetic fields to address and manipulate motional degrees of freedom. Qualitatively novel quantum effects are expected when one takes a step beyond linear coupling and exploits higher order interactions. To that end, we integrate electrical, mechanical and photonic structures in a multimode photonic crystal structure to observe "x2-coupling", where the optical cavity frequency is coupled to the square of the mechanical displacement. Moreover, we have developed two integrated on-chip platforms based on Si3N4 and Si nanomembranes capable of interfacing superconducting qubits and optical photons and realizing reversible microwave-to-optical conversion. We employ radiation pressure to cool these mechanical resonators to their quantum ground state. Finally, we demonstrate a form of electromechanical crystal for coupling microwave photons and hypersonic phonons of frequency ωm/2π = 0.425 GHz by capacitively coupling a phononic crystal acoustic cavity to a superconducting microwave resonator. Moving to higher frequency acoustic cavities not only facilitates the integration of electromechanical circuits and nanophotonic systems capable of operation in the resolved sideband limit of optomechanics for noise-free quantum signal conversion, but it opens up the possibility of using phonons as information carriers via phononic circuits. Utilizing a two-photon resonance condition for efficient microwave pumping and phononic bandgap shield to eliminate acoustic radiation, we achieve large cooperative electromechanical coupling (C ≈ 30) and intrinsic decay time of 2.3 ms. Moreover, electrical read-out of the phonon occupancy shows that the acoustic mode thermalizes close to its quantum ground-state of motion (phonon occupancy nm=1.5) at a fridge temperature of Tf = 10 mK. We conclude by considering several designs and fabrication improvements to the hypersonic electromechanical crystals that would enable them to perform quantum conversion between the electrical and acoustic domain.
Briggs, Ryan Morrow. "Hybrid Silicon Nanophotonic Devices: Enhancing Light Emission, Modulation, and Confinement." Thesis, 2011. https://thesis.library.caltech.edu/6483/1/RMBriggs_thesis_onesided.pdf.
Повний текст джерелаSilicon has become an increasingly important photonic material for communications, information processing, and sensing applications. Silicon is inexpensive compared to compound semiconductors, and it is well suited for confining and guiding light at standard telecommunication wavelengths due to its large refractive index and minimal intrinsic absorption. Furthermore, silicon-based optical devices can be fabricated alongside microelectronics while taking advantage of advanced silicon processing technologies. In order to realize complete chip-based photonic systems, certain critical components must continue to be developed and refined on the silicon platform, including compact light sources, modulators, routers, and sensing elements. However, bulk silicon is not necessarily an ideal material for many active devices because of its meager light emission characteristics, limited refractive index tunability, and fundamental limitations in confining light beyond the diffraction limit.
In this thesis, we present three examples of hybrid devices that use different materials to bring additional optical functionality to silicon photonics. First, we analyze high-index-contrast silicon slot waveguides and their integration with light-emitting erbium-doped glass materials. Theoretical and experimental results show significant enhancement of spontaneous emission rates in slot structures. We then demonstrate the integration of vanadium dioxide, a thermochromic phase-change material, with silicon waveguides to form micron-scale absorption modulators. It is shown experimentally that a 2-µm long waveguide-integrated device exhibits broadband modulation of more than 6.5 dB at wavelengths near 1550 nm. Finally, we demonstrate polymer-on-gold dielectric-loaded surface-plasmon waveguides and ring resonators coupled to silicon waveguides with 1.0±0.1 dB insertion loss. The plasmonic waveguides are shown to support a single surface mode at telecommunication wavelengths, with strong electromagnetic field confinement at the polymer-gold interface. These three device concepts show that diverse materials can be integrated with silicon waveguides to achieve enhanced light emission, broadband modulation, and strong confinement, all while retaining the advantages of the silicon photonics platform.
Barclay, Paul Edward. "Fiber-coupled nanophotonic devices for nonlinear optics and cavity QED." Thesis, 2007. https://thesis.library.caltech.edu/2448/1/thesis_double_sided.pdf.
Повний текст джерелаThe sub-wavelength optical confinement and low optical loss of nanophotonic devices dramatically enhances the interaction between light and matter within these structures. When nanophotonic devices are combined with an efficient optical coupling channel, nonlinear optical behavior can be observed at low power levels in weakly-nonlinear materials. In a similar vein, when resonant atomic systems interact with nanophotonic devices, atom-photon coupling effects can be observed at a single quanta level. Crucially, the chip based nature of nanophotonics provides a scalable platform from which to study these effects.
This thesis addresses the use of nanophotonic devices in nonlinear and quantum optics, including device design, optical coupling, fabrication and testing, modeling, and integration with more complex systems. We present a fiber taper coupling technique that allows efficient power transfer from an optical fiber into a photonic crystal waveguide. Greater than 97% power transfer into a silicon photonic crystal waveguide is demonstrated. This optical channel is then connected to a high-Q (> 40,000), ultra-small mode volume (V < (λ/n)3) photonic crystal cavity, into which we couple > 44% of the photons input to a fiber. This permits the observation of optical bistability in silicon for sub-mW input powers at telecommunication wavelengths.
To port this technology to cavity QED experiments at near-visible wavelengths, we also study silicon nitride microdisk cavities at wavelengths near 852 nm, and observe resonances with Q > 3 million and V < 15 (λ/n)3). This Q/V ratio is sufficiently high to reach the strong coupling regime with cesium atoms. We then permanently align and mount a fiber taper within the near-field an array of microdisks, and integrate this device with an atom chip, creating an "atom-cavity chip" which can magnetically trap laser cooled atoms above the microcavity. Calculations of the microcavity single atom sensitivity as a function of Q/V are presented and compared with numerical simulations. Taking into account non-idealities, these cavities should allow detection of single laser cooled cesium atoms.
Xiao, Dong. "Electronic and photonic band engineering for novel optoelectronic and nanophotonic devices." 2006. http://www.lib.ncsu.edu/theses/available/etd-04112006-205711/unrestricted/etd.pdf.
Повний текст джерела"Intensity focusing and guided wave nanophotonic devices using surface plasmon polaritons." 2012. http://library.cuhk.edu.hk/record=b5549522.
Повний текст джерела有鑒於上述種種問題,本論文集中于總結構和材料兩方面剪裁表面電漿以期達到下面的要點和目的:
(1)基於傳播電漿(PSPs) ,或者傳播電漿同局域電漿(LPRs) 的結合而發展新的簡單的器件,由此提供顯著的聚焦、電磁場和場強增強。這種器件可以應用於很多方面,包括依賴強場的生物分子傳感探測,以及非線性光學效應。
(2) 設計基於增益介臂的低損耗的納米光子學器件,這種器件能夠為納米光子器件提供切實的可行性。針對表面電漿共振和電漿結構植于的介電環境之間聯繫,獲得其理論闡釋。這一工作將可以為傳感和器件設計提供深入的理解。
本論文中我們已經得到了如下的成果:
(1)一種基於將表面電漿聚焦到金屬盤中心孔而實現級聯放大增強的SERS 激勵源被提出和理論研究。這種器件提供了準均勻,水平偏振,較大面積的強SERS 激勵源。如時域有限差分(FDTD) 方法所揭試,強度譜線和波長範圍在650-1000 nm的近場性質展混出了一系列增強模式。在最佳的增強模式下,孔洞中的電場可以使得SERS 信號獲得四次方的進一步增強。同時一種解析模型也被提出來給FDTD結果以精確的解釋。我們的模型同時揭示了通過侵化金屬盤尺度而得到八次方場增強的可能性。我們的結果表明極強的電場增強,並且聚焦的電場是平行于金屬盤平面的效果,只能在中間包含一個孔洞的中空金屬盤(HMDs) 中才可能實現。這是因為金屬盤中間絶悸的問時的存在使得孔洞邊棒的電子不能流通間隙,進進而使得高強度的電場可以存在。另一方面,在實心的金屬盤的情形下,電子流會傾向於抑制到達中心的表面電漿的強度。除了產生高度優化的SERS 熱點,這種大面積的活性孔洞在螢光增強和非線性光學中也提供了一些潛在的應用。
除了中空金屬盤,基於經由增孟輔助下PSPs 的LPRs 之間的衍射共掠,我們開發了另一種一種高度侵化的熱點。由此得到的器件被理論上分析。衍射共振的過程是經由下述過程實現的:由LPRs 實現的光場局域化, LPRs 和PSPs 相互作用,以及通過PSPs 的能量傳遞。我們的研究表明通過給PSPs 引入光學增孟,可以從一種激光過程中的到LPRs 非常強的電磁場增強。我們發現通過現實的增豆豆水平,局域電場的增強引子可以達到10⁷。因此,我們為實現依賴強電場的單分子SERS提供了一種理想的方案,並且這種方案也是一種納米激光的新機制。
(2) 基於增孟輔助的電漿共振金屬納米顆粒鏈,我們提出了一種低損耗納米尺度的波導。我們證明通過引入增孟材料或者引入適當的介電材料作為周圍環境,波導的損耗可以顯著減小。為了得到低損耗傳翰的復介電譜,我們開發了一種高效的膺正交基展開(POBE) 方法。本徵模式分析揭示了低損耗模式的物理源頭,同時給出了除了基於單體偶極共振傳輸之外能量傳輸的可能性。我們提出一種基於電子書刻蝕和化學合成納米顆粒的一種製備方案。這種電漿波導可以構成納米光學器件的基石,尤其是用於集成納米光子學線路。同時,我們原創的揭示表面電漿的物理機理的POBE 方法可以用於進一步研究優化增豆豆輔助的電漿結構,進而設計良好的納米光子器件。
本論文始於一個古老問題:宏觀尺度下基於傳統介電材料光聚焦和傳導,并最後終結於納米尺度內經由增益材料和電漿結構的表面電漿的聚焦、和引導。論文結尾,本文給出了展望以及幾種可能的器件實現方案。
Surface plasmons (SPs) are electromagnetic waves that propagate along the surface of a noble metal via fluctuations in electron density. In the last decade, SPs effects gained widespread attention for their potential application in photonic devices, sensing, surface-enhanced fluorescence, especially Surface-Enhanced Raman Scattering (SERS). Many published results have confirmed the expected strengths of SERS, hence making it possible for SERS to become a next generation ultra-sensitive biosensing platform, which may take the form of various nano-structures in order to achieve optimized hot spots. While the wavelength of SPs is closely related to material dielectric properties and has limited scope for further reduction, it is of critical importance to ensure that SPs are being generated with the highest intensity before any further application advancement is possible. Meanwhile, plasmonics has aroused longstanding interests among researchers to realize nanophotonic devices. For example, ordered arrays of closely spaced metallic nanoparticles (MNP) have been employed to transport optical signals via near-field coupling below the diffraction limit. However, radiation and absorption losses in these waveguides can be serious. New concepts for novel plasmonic devices are essential.
In light of these issues, this thesis focuses on tailoring SPs from the viewpoints of structural and material properties with the following objectives:
(1) To develop a new class of simple plasmonic devices based on tailoring of propagating surface plasmons (PSPs) or cooperation between PSPs and localized plasmon resonance (LPRs) to offer significant field focusing and intensity enhancement. It can serve a wide range of applications, including high field related biomolecular sensing and detection as well as non-linear optical effects.
(2) To design low loss nanophotonic wave guides based on gain medium, which may offer real opportunity for practical nanophotonic devices. To obtain a theoretical interpretation of relationship between surface plasmon resonance and host environment where the plasmonic structure embedded. This study should provide further insight towards sensing and device design.
We have achieved the following results in this project:
(1) A novel SERS excitation source based on focusing of surface plasmons around the center hole of a metal disk for cascaded enhancement is put forward and studied theoretically. The device offers intense SERS excitation with quasi-uniformity and horizontal polarization over a comparatively large hole. As revealed by fmite-difference time-domain (FDTD) method, the intensity spectra and the characteristics of the near field for the wavelength range of 650-1 000 nm exhibit a number of enhancement modes. Electric field intensity of the optimal mode enhances the SERS signal inside the hole by over four orders. An analytical model was also developed to gain precise interpretation on FDTD results. Our model also reveals the possibility of achieving eight orders of enhancement by optimizing the scale of the disk. Our results indicate that much higher electric field enhancement in hollow metal disks (HMDs) can only be possible when we have a hole at the centre and the direction of the focusing field is parallel to the surface of the plasmonic device. This is because of the presence of an insulating gap at the center, that higher level of electric field can exist as electrons are not allowed to flow pass the gap. On the other hand, in the case of a solid metal disk, the flow of mobile electron will tend to dampen the amplitude of the arriving SPs. In addition to generation of highly optimized hot spots for SERS, the large active hole also offers potential applications in fluorescence enhancement and nonlinear spectroscopy.
In addition to HMDs, we also develop a kind of highly optimized hot spots based on diffraction coupling between LPRs via gain-assisted PSPs. Thus derived device was theoretically analyzed. The process of diffraction coupling is achieved via localization of light by LPRs, LPRs-PSPs interplay and PSPs transfer. Our study shows that by incorporating optical gain to PSPs, a very strong boost of the electromagnetic enhancement of LPRs can be expected from a lasing process. We find that with a practical gain level, the enhancement factor of local electric field intensity can be larger than 10⁷. Hence, we offer an ideal configuration to realize high-field dependent single molecule SERS and also a newly applied physical scheme for nano-Iaser.
(2) We propose a low-loss nanoscale wave guide based on gain-assisted plasmonic resonance MNP chain. We demonstrate that by employing a gain material or even an appropriate dielectric for the host environment, waveguide loss can be reduced dramatically. A highly efficient pseudo-orthonormal basis expansion (POBE) method for obtaining the complex dielectric spectra of the low-loss transmission has been developed. Eigenmode analysis revealed the physical origin of those low-loss wave guiding modes, which opens the possibility to achieve waveguiding other than using conventional dipolar resonances of individual particles. A scheme based on electron beam lithography and chemically synthesized nanoparticles has been proposed to fabricate the device. Such plasmonic waveguides may serve as building blocks for making nanoscale optical devices especially for integrated nanophotonic circuits. Meanwhile, the originally developed POBE method, which reveals the general physical mechanism of SPs, can be used to further explore optimized gain-assisted plasmonic structures to design favorable nanophotonic devices.
This thesis begins with an old problem: light focusing and guiding in macroscopic scale with traditional dielectric, and sum up finally with SPs focusing and guiding in nanoscale with gain material and plasmonic material. An outlook is presented at last with several potential schemes for the device realization.
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.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Zhang, Haixi.
"September 2011."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 124-139).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
Chapter Chapter1 --- Introduction --- p.1
Chapter 1.1 --- Towards field intensity focusing and guiding of electromagnetic wave --- p.1
Chapter 1.2 --- Surface plasmons as a route to realize electromagnetic field focusing and waveguiding in nanoscale --- p.3
Chapter 1.3 --- Structure of this thesis --- p.10
Chapter Chapter2 --- Plasmonic near field engineering: structural and material aspects --- p.13
Chapter 2.1 --- Light focusing using near field oflocalized plasmon resonances --- p.13
Chapter 2.2 --- Plasmonic near field focusing through propagating surface plasmons --- p.30
Chapter 2.3 --- Various schemes for near field focusing through surface plasmons --- p.33
Chapter 2.4 --- Guiding surface plasmons in nanoscale --- p.35
Chapter 2.5 --- Gain-assisted surface plasmons: a different path to field enhancement and guiding --- p.38
Chapter Chapter3 --- Surface plasmons: characteristics and methodology --- p.42
Chapter 3.1 --- Characteristics of localized plasmon resonance --- p.42
Chapter 3.2 --- Localized plasmon resonance: Mie theory and its variations --- p.44
Chapter 3.3 --- Characteristics of propagating surface plasmons --- p.49
Chapter 3.4 --- Reflection Pole Method for studying propagating surface plasmons in multilayer structures --- p.55
Chapter 3.5 --- Pseudo-orthonormal basis expansion method: a new mathematical scheme for modeling surface plasmons --- p.58
Chapter Chapter4 --- High field generation through intensity focusing of propagating surface plasmons --- p.62
Chapter 4.1 --- Introduction --- p.62
Chapter 4.2 --- The hollow metal disk design and its characteristics --- p.64
Chapter 4.3 --- Quasi-uniform excitation source based on focusing of propagating surface plasmons for cascade enhancement of surface enhanced Raman scattering --- p.68
Chapter 4.4 --- Conclusions and outlook --- p.78
Chapter Chapter5 --- High field generation through intensity enhancement of localized plasmon resonance from gain-assisted diffraction coupling --- p.81
Chapter 5.1 --- Introduction --- p.81
Chapter 5.2 --- Diffraction excitation of localized plasmon resonance from propagating surface plasmons --- p.83
Chapter 5.3 --- Diffraction coupling of localized plasmon resonance through gain-assisted propagating surface plasmons --- p.89
Chapter Chapter6 --- Gain-assisted plasmonic waveguides based on nanoparticle chains: an effective device approach for achieving low loss in nanoscale dimensions --- p.97
Chapter 6.1 --- Introduction --- p.97
Chapter 6.2 --- Theoretical study of near-field particle interactions in active plasmon wave guides --- p.99
Chapter 6.3 --- Routing and splitting of electromagnetic energy in nanosphere plasmon waveguides --- p.103
Chapter 6.4 --- Conclusions --- p.107
Chapter Chapter7 --- Conclusions and outlook --- p.109
Appendix --- p.117
Bibliography --- p.124