Download or read book Nano scale Imaging and Spectroscopy of Plasmonic Systems Thermal Near fields and Phase Separation in Complex Oxides written by Andrew Crandall Jones and published by . This book was released on 2012 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical spectroscopy represents a powerful characterization technique with the ability to directly interact with the electronic, spin, and lattice excitations in matter. In addition, through implementation of ultrafast techniques, further insight into the real-time dynamics of elementary interactions can be gained. However, the resolution of far-field microscopy techniques is restricted by the diffraction limit setting a spatial resolution limit in the 100s nm to micron range for visible and IR light, respectively. This resolution is too coarse for the characterization of mesoscopic phenomena in condensed matter physics. The development of experimental techniques with nanoscale resolution and sensitivity to optical fields has been a long standing obstacle to the characterization of condensed matter systems on their natural length scales. This dissertation focuses on the fundamental near-field optical properties of surfaces and nanoscale systems as well as the utilization of nano-optical techniques, specifically apertureless scattering-type Scanning Near-field Optical Microscopy (s-SNOM), to characterize said optical properties with nanometer scale resolution. First, the s-SNOM characterization of the field enhancement associated with the localized surface plasmon resonances on metallic structures is discussed. With their ability to localize light, plasmonic nano-structures are promising candidate systems to serve as molecular sensors and nano-photonic devices; however, it is well known that particle morphology and the plasmon resonance alone do not uniquely reflect the details of the local field distribution. Here, I demonstrate the use interferometric s-SNOM for imaging of the near-fields associated with plasmonic resonances of crystalline triangular silver nano-prisms in the visible spectral range. I subsequently show the extension of the concept of a localized plasmon into the mid-IR spectral range with the characterization of near-fields of silver nano-rods. Strong spatial field variation on lengths scales as short as 20 nm is observed associated with the dipolar and quadrupolar modes of both systems with details sensitively depending on the nanoparticle structure and environment. In light of recent publications predicting distinct spectral characteristics of thermal electromagnetic near-fields, I demonstrate the extension of s-SNOM techniques through the implementation of a heated atomic force microscope (AFM) tip acting as its own intrinsic light source for the characterization of thermal near-fields. Here, I detail the spectrally distinct and orders of magnitude enhanced resonant spectral near-field energy density associated with vibrational, phonon, and phonon-polariton modes. Modeling the thermal light scattering by the AFM, the scattering cross-section for thermal light may be related to the electromagnetic local density of states (EM-LDOS) above a surface. Lastly, the unique capability of s-SNOM techniques to characterize phase separation phenomena in correlated electron systems is discussed. This measurement capability provides new microscopic insight into the underlying mechanisms of the rich phase transition behavior exhibited by these materials. As a specific example, the infrared s-SNOM mapping of the metal-insulator transition and the associated nano-domain formation in individual VO2 micro-crystals subject to substrate stress is presented. Our results have important implications for the interpretation of the investigations of conventional polycrystalline thin films where the mutual interaction of constituent crystallites may affect the nature of phase separation processes.
Download or read book Photo Thermal Spectroscopy with Plasmonic and Rare Earth Doped Nano Materials written by Ali Rafiei Miandashti and published by Springer. This book was released on 2018-12-30 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the theoretical foundations of and experimental techniques in photothermal heating and applications involving nanoscale heat generation using gold nanostructures embedded in various media. The experimental techniques presented involve a combination of nanothermometers doped with rare-earth atoms, plasmonic heaters and near-field microscopy. The theoretical foundations are based on the Maxwell’s and heat diffusion equations. In particular, the working principle and application of AlGaN:Er3+ film, Er2O3 nanoparticles and β-NaYF4:Yb3+,Er3+ nanocrystals for nanothermometry based on Er3+ emission are discussed. The relationship between superheated liquid and bubble formation for optically excited nanostructures and the effects of the surrounding medium and solution properties on light absorption and scattering are presented. The application of Er2O3 and β-NaYF4:Yb3+,Er3+ nanocrystals to study the temperature of optically heated gold nanoparticles is also presented. In closing, the book presents a new thermal imaging technique combining near-field microscopy and Er3+ photoluminescence spectroscopy to monitor the photothermal heating and steady-state sub-diffraction local temperature of optically excited gold nanostructures.
Download or read book Optical Characterization of Plasmonic Nanostructures Near Field Imaging of the Magnetic Field of Light written by Denitza Denkova and published by Springer. This book was released on 2016-04-20 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on a means of obtaining, for the first time, full electromagnetic imaging of photonic nanostructures. The author also develops a unique practical simulation framework which is used to confirm the results. The development of innovative photonic devices and metamaterials with tailor-made functionalities depends critically on our capability to characterize them and understand the underlying light-matter interactions. Thus, imaging all components of the electromagnetic light field at nanoscale resolution is of paramount importance in this area. This challenge is answered by demonstrating experimentally that a hollow-pyramid aperture probe SNOM can directly image the horizontal magnetic field of light in simple plasmonic antennas – rod, disk and ring. These results are confirmed by numerical simulations, showing that the probe can be approximated, to first order, by a magnetic point-dipole source. This approximation substantially reduces the simulation time and complexity and facilitates the otherwise controversial interpretation of near-field images. The validated technique is used to study complex plasmonic antennas and to explore new opportunities for their engineering and characterization.
Download or read book Plasmonic Platform for Super resolution Imaging and Applications in Biological and Nanoenergetic Systems written by Biyan Chen and published by . This book was released on 2017 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmonics, taking advantages of coupling photons to free electrons in metals, enables prominent electromagnetic field enhancements by concentrating light into subwavelength scales, allowing super resolution imaging, enhancement of fluorescence and photothermal heating. In this dissertation, a plasmonic grating platform prepared by nano-imprint lithography was introduced for imagingnanostructures, biological materials, and diagnostics of nanoenergetic systems. First, a glancing angledeposition technique was developed to combine periodic gratings with nano-protrusion for single moleculesuper-resolution imaging for dye-labeled DNA/RNA duplex in wide dye concentrations. The combination of the plasmonic probes and localization microscopy can resolve features as small as 65 nm. Then, the subwavelength nanoparticles with various shapes were studied by different super-resolution approaches. Further, the plasmonic grating microchips facilitate a robust in-situ diagnostic platform for the laser-induced photothermal heating and combustion of aluminum nanoparticles (Al NPs)-fluoropolymer nanoenergetic films. A fluorescence-based temperature sensor with temperature-sensitive dye was developed for dynamic thermal mapping at the nanoscale. The plasmonic grating enables visualization and initialization of localized nano-flames whose temperatures were obtained by two-color pyrometry. Scattering measurements enabled precise identification of individual Al NPs over a large field of view, leading to 3D reconstruction of combustion events
Download or read book Nonlinear Spectroscopy written by Società italiana di fisica and published by Elsevier Science & Technology. This book was released on 1977 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plasmonic Nano imaging and Nanofabrication written by Satoshi Kawata and published by SPIE-International Society for Optical Engineering. This book was released on 2005 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of SPIE present the original research papers presented at SPIE conferences and other high-quality conferences in the broad-ranging fields of optics and photonics. These books provide prompt access to the latest innovations in research and technology in their respective fields. Proceedings of SPIE are among the most cited references in patent literature.
Download or read book Spatiotemporally Resolved Photoemission from Plasmonic Nanoparticles written by Jianxiong Li and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Streaked photoemission from nanostructured surfaces and nanoparticles by attosecond extreme ultraviolet (XUV) pulses into an infrared (IR) or visible streaking pulse allows for sub-femtosecond resolution of the plasmonically enhanced streaking-pulse electric field. It holds promise for the temporally and spatially resolved imaging of the dielectric response near nanostructures. In this dissertation, I present four distinct yet interconnected aspects of numerically modeling plasmonic reconstruction by the photoemission from nanoparticles. First, I present a theoretical model of simulating the IR-streaked XUV photoemission spectra, by calculating (a) the plasmonic field induced by IR pulses within Mie theory, and (b) the T-matrix elements for photoemission using a quantum-mechanical model. The simulation results show significant oscillation-amplitude enhancements and phase shifts, comparing to calculations without the induced plasmonic field. These observable effects can be traced to the dielectric properties of the nanoparticles, demonstrating the applicability of streaking spectroscopy to the investigation of induced plasmonic effect near nanoparticles and nanostructured surfaces. Second, based on this model, I propose a scheme for the reconstruction of plasmonic near-fields at isolated nanoparticles from streaked photoelectron spectra. The success of this proposed scheme is demonstrated by the accurate imaging of the IR-streaking-pulse-induced plasmonic fields at the surface of gold nanospheres and nanoshells with sub-femtosecond temporal and sub-nanometer spatial resolution. Third, I further improve the physical accuracy of the model, by developing a semi-classical approach, ACCTIVE, to solve the time-dependent Schrödinger's equation in spatially inhomogeneous electromagnetic fields. I demonstrate the validation of this method by studying electron final-state wavefunctions in Coulomb and laser fields, before applying these improved final photoelectron states to streaked photoemission from hydrogen atoms. The results show excellent quantitative agreement with direct solution of the Schrödinger's equation. Implementing this method to simulating the streaked photoemission from Au nanospheres shows better agreement in plasmonic-field reconstruction for low energy photoelectrons than previous strong-field-approximation simulations. Finally, I extend the previous work and explore the non-linear optical response of nanoparticles observed in momentum imaging experiments at the Kansas State University Department of Physics. My Mie simulations, by including intensity-dependent index of refraction, show a significant non-linear effect in SiO2-core-Au-shell nanoparticles in response to 1010 - 1012 TW/cm2 intensity and 780 nm central wavelength IR pulses. This effect is responsible for the change in the experimentally observed photoelectron "cut-off" energies, as a function of the external pulse intensity, suggesting the non-linear optical response to be a significant factor in strong-field photoemission from plasmonic nanoparticles.
Download or read book Nanoscale Spectroscopy with Applications written by Sarhan M. Musa and published by CRC Press. This book was released on 2018-10-08 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the key concepts of nanoscale spectroscopy methods used in nanotechnologies in a manner that is easily digestible for a beginner in the field. It discusses future applications of nanotechnologies in technical industries. It also covers new developments and interdisciplinary research in engineering, science, and medicine. An overview of nanoscale spectroscopy for nanotechnologies, the book describes the technologies with an emphasis on how they work and on their key benefits. It also serves as a reference for veterans in the field.
Download or read book Collective Plasmon Modes in Gain Media written by V.A.G. Rivera and published by Springer. This book was released on 2014-09-03 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book represents the first detailed description, including both theoretical aspects and experimental methods, of the interaction of rare-earth ions with surface plasmon polariton from the point of view of collective plasmon-photon interactions via resonance modes (metal nanoparticles or nanostructure arrays) with quantum emitters (rare-earth ions). These interactions are of particular interest for applications to optical telecommunications, optical displays, and laser solid state technologies. Thus, our main goal is to give a more precise overview of the rapidly emerging field of nanophotonics by means of the study of the quantum properties of light interaction with matter at the nanoscale. In this way, collective plasmon-modes in a gain medium result from the interaction/coupling between a quantum emitter (created by rare-earth ions) with a metallic surface, inducing different effects such as the polarization of the metal electrons (so-called surface plasmon polariton - SPP), a field enhancement sustained by resonance coupling, or transfer of energy due to non-resonant coupling between the metallic nanostructure and the optically active surrounding medium. These effects counteract the absorption losses in the metal to enhance luminescence properties or even to control the polarization and phase of quantum emitters. The engineering of plasmons/SPP in gain media constitutes a new field in nanophotonics science with a tremendous technological potential in integrated optics/photonics at the nanoscale based on the control of quantum effects. This book will be an essential tool for scientists, engineers, and graduate and undergraduate students interested not only in a new frontier of fundamental physics, but also in the realization of nanophotonic devices for optical telecommunication.
Download or read book Nano Optics for Enhancing Light Matter Interactions on a Molecular Scale written by Baldassare Di Bartolo and published by Springer. This book was released on 2012-12-03 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents a considerable number of interrelated contributions dealing with the new scientific ability to shape and control matter and electromagnetic fields on a sub-wavelength scale. The topics range from the fundamental ones, such as photonic metamateriials, plasmonics and sub-wavelength resolution to the more applicative, such as detection of single molecules, tomography on a micro-chip, fluorescence spectroscopy of biological systems, coherent control of biomolecules, biosensing of single proteins, terahertz spectroscopy of nanoparticles, rare earth ion-doped nanoparticles, random lasing, and nanocoax array architecture. The various subjects bridge over the disciplines of physics, biology and chemistry, making this volume of interest to people working in these fields. The emphasis is on the principles behind each technique and on examining the full potential of each technique. The contributions that appear in this volume were presented at a NATO Advanced Study Institute that was held in Erice, Italy, 3-18 July, 2011. The pedagogical aspect of the Institute is reflected in the topics presented in this volume.
Download or read book Plasmonic and Near Field Phenomena in Low Dimensional Nanostructures written by Bor-Yuan Jiang and published by . This book was released on 2018 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmonics aims to combine the advantages of nanometer scale electronics with the high operating frequency (terahertz and beyond) of photonics. Control of plasmon propagation can be achieved in a two-dimensional electron gas (2DEG) by tuning the electronic properties of the 1D nanostructures it contains, which act as scatters for plasmons. Plasmonic response of these nanostructures, however, happens on a length scale much smaller than the wavelength of free space electromagnetic radiation and cannot be studied with conventional optical microscopy. Instead, we resolve these nanoscopic phenomena using near-field optical microscopy, which has a spatial resolution of $\sim 20\,\mathrm{nm}$. In this dissertation, we first describe the working principles of near-field optical microscopy, then analyze the plasmonic phenomena we observed around several 1D nanostructures, including a potential well in monolayer graphene, domain walls in bilayer graphene, and a low-conductivity gap in a 2DEG. In Chapter 1, we give an overview of the basic properties of surface plasmons and graphene, followed by a brief explanation of the operating principles of near-field optical microscopy. In Chapter 2, we study theoretically the electromagnetic interaction between a sub-wavelength particle (the 'probe') and a material surface (the 'sample'). The interaction is shown to be governed by a series of resonances corresponding to surface polariton modes localized near the probe. The resonance parameters depend on the dielectric function and geometry of the probe, as well as the surface reflectivity of the material. Calculation of such resonances is carried out for several types of axisymmetric probes: spherical, spheroidal, and pear-shaped. For spheroids an efficient numerical method is developed, capable of handling cases of large or strongly momentum-dependent surface reflectivity. Application of the method to highly resonant materials such as aluminum oxide (by itself or covered with graphene) reveals a rich structure of multi-peak spectra and nonmonotonic approach curves, i.e., the probe-sample distance dependence. These features also strongly depend on the probe shape and optical constants of the model. For less resonant materials such as silicon oxide, the dependence is weak, so that the spheroidal model is reliable. The calculations are done within the quasistatic approximation with radiative damping included perturbatively. In Chapter 3, we show that surface plasmons of a two-dimensional Dirac metal such as graphene can be reflected by line-like perturbations hosting one-dimensional electron states. The reflection originates from a strong enhancement of the local optical conductivity caused by optical transitions involving these bound states. We propose that the bound states can be systematically created, controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared nanoimaging, we obtain experimental evidence for the locally enhanced conductivity of graphene induced by a carbon nanotube gate, which supports this theoretical concept. In Chapter 4, we show that topological bound states confined to the domain walls in bilayer graphene are the source of the wall's strong coupling to surface plasmons observed in infrared nanoimaging experiments. These domain walls separate regions of $\mathrm{AB}$ and $\mathrm{BA}$ interlayer stacking and have attracted attention as novel examples of structural solitons, topological electronic boundaries, and nanoscale plasmonic scatterers. The optical transitions among the topological chiral modes and the band continua enhance the local conductivity, which leads to plasmon reflection by the domain walls. The imaging reveals two kinds of plasmonic standing-wave interference patterns, which we attribute to shear and tensile domain walls. We compute the electronic structure of both wall varieties and show that the tensile wall contains additional confined bands which produce a structure-specific contrast of the local conductivity, in agreement with the experiment. The coupling between the confined modes and the surface plasmon scattering unveiled in this work is expected to be common to other topological electronic boundaries found in van der Waals materials. This coupling provides a qualitatively new pathway toward controlling plasmons in nanostructures. In Chapter 5, we present a comprehensive study of the reflection of normally incident plasmon waves from a low-conductivity 1D junction in a 2D conductive sheet. Rigorous analytical results are derived in the limits of wide and narrow junctions. Two types of phenomena determine the reflectance, the cavity resonances within the junction and the capacitive coupling between the leads. The resonances give rise to alternating strong and weak reflection but are vulnerable to plasmonic damping. The capacitive coupling, which is immune to damping, induces a near perfect plasmon reflection in junctions narrower than $1/10$ of the plasmon wavelength. Our results are important for 2D plasmonic circuits utilizing slot antennas, split gates or nanowire gates. They are also relevant for the implementation of nanoscale terahertz detectors, where optimal light absorption coincides with the maximal junction reflectance.
Download or read book Plasmonic Control of Light Emission written by Young Chul Jun and published by Stanford University. This book was released on 2010 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced light-matter interactions in light-confining structures (such as optical cavities) have been extensively investigated for both fundamental studies and practical applications. Plasmonic nanostructures, which can confine and manipulate light down to ~1 nm scale, are becoming increasingly important. Many areas of optical physics and devices can benefit from such extreme light concentration and manipulation. For example, fluorescent molecule or quantum dot (QD) emission can be strongly modified and controlled via surface plasmon polariton (SPP) coupling. In this dissertation, we present our theoretical and experimental studies on QD emission in metal nanogap structures that can provide extreme field concentration, enhancing light-matter interactions significantly. We start with a theoretical analysis of dipole emission in metal-dielectric-metal (MDM) waveguide structures. We look at both infinite (i.e. planar) and finite thickness MDM structures. We find that both structures exhibit strong spontaneous emission enhancements due to the tight confinement of modes between two metallic plates and that light emission is dominated by gap SPP coupling. For planar structures we present analytical solutions for the enhanced dipole decay rate, while for finite thickness MDM structures (i.e. nanoslits) we present results from numerical simulations. Next, we present our experiments on the SPP coupling of CdSe/ZnS QD emission in metal nanoslits. First, we observed clear lifetime and polarization state changes of QD emission with slit width due to gap SPP excitation. Second, with optimized side grooves (i.e. combined slit-groove and hole-groove structures), we collimated QD emission vertically into a very narrow angle, achieving an unprecedented level of directionality control, and visualized it with confocal scanning microscopy. Third, by using two metal plates as electrodes, we dynamically modulated the QD emission intensity and wavelength with external voltage. Finally, we extend our dipole emission calculation to several slot waveguide structures. We consider light emission in metal slots, metal-oxide-Si slots, and Si slot waveguides. We find that large spontaneous emission enhancements can be obtained over a broad range of wavelengths and that light emission is strongly funneled into slot waveguide modes. These represent broadband waveguide QED (quantum electro-dynamics) systems, which have unique merits for on-chip light sources and quantum information processing. These theoretical and experimental studies show that the SPP coupling of light emission is a very promising way to control light emission properties and may find broad application in spectroscopy, sensing, optoelectronics, and integrated optics.
Download or read book Nanoscale Photonic Imaging written by Tim Salditt and published by Springer. This book was released on 2020-07-17 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Open Access volume, edited and authored by a team of world-leading researchers, provides a broad overview of advanced photonic methods for nanoscale visualization, as well as describing a range of fascinating in-depth studies. Introductory chapters cover the most relevant physics and basic methods that young researchers need to master in order to work effectively in the field of nanoscale photonic imaging, from physical first principles, to instrumentation, to mathematical foundations of imaging and data analysis. Subsequent chapters demonstrate how these cutting edge methods are applied to a variety of systems, including complex fluids and biomolecular systems, for visualizing their structure and dynamics, in space and on timescales extending over many orders of magnitude down to the femtosecond range. Progress in nanoscale photonic imaging in Göttingen has been the sum total of more than a decade of work by a wide range of scientists and mathematicians across disciplines, working together in a vibrant collaboration of a kind rarely matched. This volume presents the highlights of their research achievements and serves as a record of the unique and remarkable constellation of contributors, as well as looking ahead at the future prospects in this field. It will serve not only as a useful reference for experienced researchers but also as a valuable point of entry for newcomers.
Download or read book Super Resolution Imaging of Plasmonic Near fields written by Yuting Miao and published by . This book was released on 2021 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmonic nano-objects have shown great potential in enhancing sensing, energy transfer and computing, and there has been much e↵ort to optimize plasmonic systems and exploit their field enhancement properties. Super-resolution imaging with quantum dots (QDs) is a promising method to probe plasmonic near-fields. However, due to the strong coupling between QDs and plasmons, this technique is hindered by the formation of distorted point spread functions (PSFs) and QD mislocalizations. Chapter 4 of this dissertation investigates the coupling between QDs and 'L-shaped' gold nanostructures, and demonstrates both theoretically and experimentally that this strong coupling can induce polarization- / wavelength-dependent changes to the apparent QD emission intensity, polarization and position. From the magnitude and direction of the PSF shift under emission polarization modulation, the coupling strength can be extracted, and the true PSF location can be back-calculated from tabulated theoretical and experimental values. This discovery helps to better apply super-resolution imaging techniques to detect the plasmonic near-fields.Besides using fluorescence intensity as the local-field intensity indicator, photophysical properties of the emitter (e.g. on-time ratio) have shown to be a great candidate as well. Super-resolution fluctuation imaging (SOFI) has great potential in extracting the photophysical properties of emitters with super-resolution. In chapter 5, I discuss an open-source, modular SOFI analysis package we built for both reconstructing super-resolved plasmonic near-fields and engaging the SOFI community with a wide range of applications. Chapter 6 demonstrates how we characterize the photophysical properties of a specific fluorescent protein suitable for SOFI analysis. Our work provides a practical method with higher precision for plasmonic near-field mapping, which benefits many applications like biosensing and optical quantum computing.
Download or read book Plasmonics in the Near infrared written by Kevin Tetz and published by . This book was released on 2006 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of nanophotonics is finding myriad applications in telecommunications and information technology, microscopy, lighting, and sensing. There is general interest in highly confined and nanoscale optical modes for a number of these applications, with a particular interest in structures that confine electromagnetic fields and energy in volumes smaller than the free space wavelength. Plasmonics, the utilization of coupled photon-plasmon waves in systems with free electrons, in micro- and nanoscale geometric structures has attracted significant recent attention for these purposes. In this dissertation we explore surface plasmon-polariton (SPP) fields, on nanostructured metal-dielectric boundaries, at frequencies in the near-infrared portion of the electromagnetic spectrum. To couple to these SPP modes from free-space propagating light, arrays of nanoholes etched in metal films are employed. We then utilize a variety of experimental techniques that investigate the physics of SPPs in space, time, and frequency. Various physical phenomena, including enhanced transmission effects and resonantly excited and propagating surface electromagnetic modes, are observed, studied, and explained. We begin by discussing the basics of SPP excitation and modal propagation properties and present an analytical investigation of gain assisted propagation. We next investigate the spatial and spectral frequency dependent transmission through nanohole arrays. We present novel experimental and analytic results of polarization dependent Fano-type lineshape profiles present in enhanced transmission due to SPP excitation. We further present a method for excitation and direct imaging of SPPs from nanohole arrays and demonstrate coupling to a variety of modes with different in-plane propagating wavevector components. This method is extended to incorporate ultrashort laser pulse excitation and enables space-time imaging of ultrashort SPP fields, both in spatial amplitude and phase, with femtosecond time scale resolution. We ultimately describes the application of this work to the making of a highly parallelized sensor to measure chemical reactions at a surface by generating spatially resolved, reaction dependent, spatial and spectral frequency information.
Download or read book A Short Course on Topological Insulators written by János K. Asbóth and published by Springer. This book was released on 2016-02-22 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This course-based primer provides newcomers to the field with a concise introduction to some of the core topics in the emerging field of topological insulators. The aim is to provide a basic understanding of edge states, bulk topological invariants, and of the bulk--boundary correspondence with as simple mathematical tools as possible. The present approach uses noninteracting lattice models of topological insulators, building gradually on these to arrive from the simplest one-dimensional case (the Su-Schrieffer-Heeger model for polyacetylene) to two-dimensional time-reversal invariant topological insulators (the Bernevig-Hughes-Zhang model for HgTe). In each case the discussion of simple toy models is followed by the formulation of the general arguments regarding topological insulators. The only prerequisite for the reader is a working knowledge in quantum mechanics, the relevant solid state physics background is provided as part of this self-contained text, which is complemented by end-of-chapter problems.
Download or read book Contribution to Photochemical Imaging of Complex Plasmonic Fields written by Yinping Zhang and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmonic oligomers are near-field coupled assemblies of metallic nanoparticles. Both their scattering/absorption spectra and the spatial distribution of the electromagnetic field can be tailored through the hybridization of plasmonic modes hosted by individual particles. Such a control on the field distribution open new routes to deliver light at a deep subwavelength scale in targeted locations (“hot spots”). However, active control of hot spots in plasmonic oligomers and their observation in the near field are highly challenging. In this thesis, we propose to use a two-photon absorption process in photosensitive azobenzene-containing polymer in the near infrared to imprint from the far field the near field distribution around linear trimer nanoantenna, triangle trimer nanoantenna and bowtie dimer nanoantenna, respectively. This work shows that bonding and anti-bonding gap modes under these simple plasmonic oligomers can be selectively excited by remotely controlled through the angle of incident and the polariztion state of light, resulting in controlled hot spot locations. Two-photon absorption by azobenzene-containing photopolymer turns out to be a reliable approach for investigating confined plasmonic fields in the near infrared with a 20 nm resolution.
