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 Devices Employing Extreme Light Concentration written by Ragip Pala and published by Stanford University. This book was released on 2010 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of integrated electronic and photonic circuits has led to remarkable data processing and transport capabilities that permeate almost every facet of our daily lives. Scaling these devices to smaller and smaller dimensions has enabled faster, more power efficient and inexpensive components but has also brought about a myriad of new challenges. One very important challenge is the growing size mismatch between electronic and photonic components. To overcome this challenge, we will need to develop radically new device technologies that can facilitate information transport between nanoscale components at optical frequencies and form a bridge between the world of nano-electronic and micro-photonics. Plasmonics is an exciting new field of science and technology that aims to exploit the unique optical properties of metallic nanostructures to gain a new level of control over light-matter interactions. The use of nanometallic (plasmonic) structures may help bridge the size gap between the two technologies and enable an increased synergy between chip-scale electronics and photonics. In the first part of this dissertation we analyze the performance of a surface plasmon-polariton all-optical switch that combines the unique physical properties of small molecules and metallic (plasmonic) nanostructures. The switch consists of a pair of gratings defined on an aluminum film coated with a thin layer of photochromic (PC) molecules. The first grating couples a signal beam consisting of free space photons to SPPs that interact effectively with the PC molecules. These molecules can reversibly be switched between transparent and absorbing states using a free space optical pump. In the transparent (signal "on") state, the SPPs freely propagate through the molecular layer, and in the absorbing (signal "off") state, the SPPs are strongly attenuated. The second grating serves to decouple the SPPs back into a free space optical beam, enabling measurement of the modulated signal with a far-field detector. We confirm and quantify the switching behavior of the PC molecules by using a surface plasmon resonance spectroscopy. The quantitative experimental and theoretical analysis of the nonvolatile switching behavior guides the design of future nanoscale optically or electrically pumped optical switches. In the second part of the dissertation we provide a critical assessment of the opportunities for use of plasmonic nanostructures in thin film solar cell technology. Thin-film solar cells have attracted significant attention as they provide a viable pathway towards reduced materials and processing costs. Unfortunately, the materials quality and resulting energy conversion efficiencies of such cells is still limiting their rapid large-scale implementation. The low efficiencies are a direct result of the large mismatch between electronic and photonic length scales in these devices; the absorption depth of light in popular PV semiconductors tends to be longer than the electronic (minority carrier) diffusion length in deposited thin-film materials. As a result, charge extraction from optically thick cells is challenging due to carrier recombination in the bulk of the semiconductor. We discuss how light absorption could be improved in ultra-thin layers of active material making use of large scattering cross sections of plasmonic structures. We present a combined computational-experimental study aimed at optimizing plasmon-enhanced absorption using periodic and non-periodic metal nanostructure arrays.
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 Chiral Nanophotonics written by Martin Schäferling and published by Springer. This book was released on 2016-11-11 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the physics behind the optical properties of plasmonic nanostructures focusing on chiral aspects. It explains in detail how the geometry determines chiral near-fields and how to tailor their shape and strength. Electromagnetic fields with strong optical chirality interact strongly with chiral molecules and, therefore, can be used for enhancing the sensitivity of chiroptical spectroscopy techniques. Besides a short review of the latest results in the field of plasmonically enhanced enantiomer discrimination, this book introduces the concept of chiral plasmonic near-field sources for enhanced chiroptical spectroscopy. The discussion of the fundamental properties of these light sources provides the theoretical basis for further optimizations and is of interest for researchers at the intersection of nano-optics, plasmonics and stereochemistry.
Download or read book Near Field Mediated Photon Electron Interactions written by Nahid Talebi and published by Springer Nature. This book was released on 2019-11-16 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the use of novel electron microscopy techniques to further our understanding of the physics behind electron–light interactions. It introduces and discusses the methodologies for advancing the field of electron microscopy towards a better control of electron dynamics with significantly improved temporal resolutions, and explores the burgeoning field of nanooptics – the physics of light–matter interaction at the nanoscale – whose practical applications transcend numerous fields such as energy conversion, control of chemical reactions, optically induced phase transitions, quantum cryptography, and data processing. In addition to describing analytical and numerical techniques for exploring the theoretical basis of electron–light interactions, the book showcases a number of relevant case studies, such as optical modes in gold tapers probed by electron beams and investigations of optical excitations in the topological insulator Bi2Se3. The experiments featured provide an impetus to develop more relevant theoretical models, benchmark current approximations, and even more characterization tools based on coherent electron–light interactions.
Download or read book Plasmon enhanced light matter interactions written by Peng Yu and published by Springer Nature. This book was released on 2022-03-01 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights cutting-edge research in surface plasmons, discussing the different types and providing a comprehensive overview of their applications. Surface plasmons (SPs) receive special attention in nanoscience and nanotechnology due to their unique optical, electrical, magnetic, and catalytic properties when operating at the nanoscale. The excitation of SPs in metal nanostructures enables the manipulation of light beyond the diffraction limit, which can be utilized for enhancing and tailoring light-matter interactions and developing ultra-compact high-performance nanophotonic devices for various applications. With clear and understandable illustrations, tables, and descriptions, this book provides physicists, materials scientists, chemists, engineers, and their students with a fundamental understanding of surface plasmons and device applications as a basis for future developments.
Download or read book Near Field Characterization of Plasmonic Nanostructures with Electron Energy Loss Spectroscopy written by and published by . This book was released on 2014 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Plasmon Nanophotonics written by Mark L. Brongersma and published by Springer. This book was released on 2007-09-18 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses a new class of photonic devices, known as surface plasmon nanophotonic structures. The book highlights several exciting new discoveries, while providing a clear discussion of the underlying physics, the nanofabrication issues, and the materials considerations involved in designing plasmonic devices with new functionality. Chapters written by the leaders in the field of plasmonics provide a solid background to each topic.
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 Near Field Optics and Surface Plasmon Polaritons written by Satoshi Kawata and published by Springer Science & Business Media. This book was released on 2001-06-20 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This up-to-date overview describes in detail the physics of localized surface plasmon polaritons excited near fine metallic structures and the principles of near-field optics and microscopy related to this localized field. It also covers wider fields, from local spectroscopy to atom manipulation.
Download or read book Optical Properties of Nanostructured Metallic Systems written by Sergio G. Rodrigo and published by Springer Science & Business Media. This book was released on 2011-10-08 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: The common belief is that light is completely reflected by metals. In reality they also exhibit an amazing property that is not so widely known: under some conditions light flows along a metallic surface as if it were glued to it. Physical phenomena related to these light waves, which are called Surface Plasmon Polaritons (SPP), have given rise to the research field of plasmonics. This thesis explores four interesting topics within plasmonics: extraordinary optical transmission, negative refractive index metamaterials, plasmonic devices for controlling SPPs, and field enhancement phenomena near metal nanoparticles.
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 Optical Properties of Metallic Nanoparticles written by Andreas Trügler and published by Springer. This book was released on 2016-03-29 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the fascinating world of plasmonics and physics at the nanoscale, with a focus on simulations and the theoretical aspects of optics and nanotechnology. A research field with numerous applications, plasmonics bridges the gap between the micrometer length scale of light and the secrets of the nanoworld. This is achieved by binding light to charge density oscillations of metallic nanostructures, so-called surface plasmons, which allow electromagnetic radiation to be focussed down to spots as small as a few nanometers. The book is a snapshot of recent and ongoing research and at the same time outlines our present understanding of the optical properties of metallic nanoparticles, ranging from the tunability of plasmonic resonances to the ultrafast dynamics of light-matter interaction. Beginning with a gentle introduction that highlights the basics of plasmonic interactions and plasmon imaging, the author then presents a suitable theoretical framework for the description of metallic nanostructures. This model based on this framework is first solved analytically for simple systems, and subsequently through numerical simulations for more general cases where, for example, surface roughness, nonlinear and nonlocal effects or metamaterials are investigated.
Download or read book Singular and Chiral Nanoplasmonics written by Svetlana Boriskina and published by CRC Press. This book was released on 2014-10-27 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmonics has already revolutionized molecular imaging, cancer research, optical communications, sensing, spectroscopy, and metamaterials development. This book is a collective effort by several research groups to push the frontiers of plasmonics research into the emerging area of harnessing and generation of photon angular momentum on micro- and nanoscales. It offers a glimpse into the ongoing research efforts to develop new types of plasmonic vortex–pinning platforms and chiral nanostructures for light harvesting, bio(chemical) sensing, drug discovery, and nanoscale energy transfer.
Download or read book Plasmonic Nanoguides and Circuits written by Sergey Bozhevolnyi and published by CRC Press. This book was released on 2019-05-08 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the authors concentrate on the surface Plasmon (SP) waveguide configurations ensuring nanoscale confinement and review the current status of this rapidly emerging field, considering different configurations being developed for nanoscale plasmonic guides and circuits. Both fundamental physics and application aspects of plasmonics are reviewed in detail by the world's leading experts. A unique feature of this book is its strong focus on a particular subfield of plasmonics dealing with subwavelength (nanoscale) waveguiding, an area which is especially important in view of the explosively growing interest in plasmonic interconnects and nanocircuits.
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 From Classical to Quantum Plasmonics in Three and Two Dimensions written by Thomas Christensen and published by Springer. This book was released on 2017-01-11 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis provides a comprehensive introduction to two active research directions within the field of plasmonics: (i) nonclassical, or quantum, aspects of the plasmonic response; and (ii) two-dimensional plasmonics, a recent innovation in the field stimulated by the advent of two-dimensional materials. It discusses the fundamentals of this field in detail, and explores several current research directions. Nonclassical plasmonics has been spurred on in recent years by the tremendous technological progress in nanofabrication and optical characterization; today, it is possible to investigate the plasmonic features of nanostructures with characteristic features in the few nanometer range. The book describes and analyzes the breakdown of the classical theory under these conditions and explores several alternatives and extensions. The unique electronic and dimensional features of novel two-dimensional materials, such as graphene, lie at the core of plasmonics' most rapidly developing subfield; two-dimensional plasmonics. This thesis provides a clear and comprehensive exposition of the central features for interested researchers looking for an entry point to this riveting area.
