World Scientific Handbook of Metamaterials and Plasmonics

The following sections are included:

• Preface by Main Editor
• Preface by Volume Editor
• Contents

This chapter presents homogenization principles for metamaterials and dielectric mixtures. The focus is on the principles with which homogenization brings forth emergence: such qualitatively new properties in the effective characterization that are not present in the constituent components that make the medium. The classical Maxwell Garnett mixing result is paralleled with the deterministic scattering problem of a composite sphere, and the resulting equivalence is exploited in translating known mixing results to scattering and absorption properties of simple scatterers and vice versa. Emphasis is given to the way mixing can lead to situations where the composite obeys an unexpected dispersion behavior that is not directly predictable from the knowledge of the dispersion of the component materials. The characteristics of the localized resonances and their dependence on geometrical and structural parameters in plasmonic nanoparticles are analyzed. Theoretical bounds for the effective permittivity of mixtures are discussed as well as situations in which these bounds can allow enhanced polarization and percolation effects. Finally, anisotropic and in particular hyperbolic media are modelled with a special application to radially anisotropic (RA) particles which may display surprising macroscopic effects like, for example, anomalous absorption.

Here, we present an overview of recent developments in the characterization of electromagnetic and quantum metamaterials using effective medium methods. It is highlighted that both electromagnetic and electronic systems can be homogenized in a unified manner based on the introduction of an effective Hamiltonian operator that describes the time evolution of the macroscopic initial states as well as the stationary states of the relevant system. Furthermore, it is shown that in some circumstances quadratic forms of the fields, such as the energy, can be exactly determined using the effective medium theory.

Hyperbolic metamaterials were originally introduced to overcome the diffraction limit of optical imaging. Soon thereafter, it was realized that hyperbolic metamaterials demonstrate a number of novel phenomena resulting from the broadband singular behavior of their density of photonic states. These novel phenomena and applications include super-resolution imaging, new stealth technologies, enhanced quantum electrodynamic effects, thermal hyperconductivity, superconductivity and interesting gravitation theory analogs. Here, we briefly review typical material systems which exhibit hyperbolic behavior and outline important applications of hyperbolic metamaterials.

Extraordinary transmission of electromagnetic waves through periodic arrays of electrically small apertures has attracted the attention of many researchers since the discovery of such phenomenon at the end of the 1990s. The explanation of the existence of such frequency-selective enhanced transmission behavior has been linked to the interaction of the impinging uniform plane wave with the so-called (spoof) surface plasmon-polaritons supported by the periodically structured surface. However, an alternative model has also been proposed in the literature which is based on the consideration of the unit cell of the periodic system as a waveguide discontinuity problem. This problem is very common in the classical microwave-engineering literature and is usually treated under the standpoint of equivalent-circuit modelling. Circuit models have a number of obvious advantages related to their analytical or quasi-analytical nature. Thus, the computational effort is negligible when compared with standard numerical approaches. But, more importantly, these models provide a simplified conceptual frame that makes the understanding of the underlying physical phenomena easier. This chapter provides a review of circuit–like models available in the literature to deal with the transmission of electromagnetic waves through periodically structured screens.

The following sections are included:

• Introduction
• Metasurface Mathematical Synthesis
• Scattering Particle Synthesis and Implementation
• Discussions
• Conclusion
• Appendix
• References

This chapter discusses most general linear bianisotropic metasurfaces and reviews various homogenization models and methods to synthesize metasurfaces with desired reflection and transmission properties. In the last part, we give several examples of metasurface synthesis, illustrating a general approach to realizing the desired and optimized response. The focus is on understanding and selecting physical properties of unit cells which are most suitable for realizing the desired response of metasurfaces, and on finding appropriate topologies and dimensions of the unit cells.

The ability to engineer and control the electromagnetic scattering from material bodies is of great importance in modern science and technology. In this chapter, we review some of the most exciting recent advances in this topic, enabled or inspired by metamaterials and plasmonics. We discuss, from a fundamental perspective, how to drastically suppress or enhance the scattering cross-section of a given object, as well as how to increase the lifetime of scattering resonances and the directivity of the scattering pattern. The possibility to control scattering processes “at the extreme” with metamaterials may find application in many diverse practical scenarios, including cloaking and invisibility, light trapping, energy harvesting, biochemical sensing and enhanced light–matter interaction at the micro- and nanoscale.

This chapter reviews a novel, rapidly developing field of modern light science named all-dielectric nanophotonics. This branch of nanophotonics is based on the properties of high-index dielectric nanoparticles which allow for controlling both magnetic and electric responses of a nanostructured matter. Here, we discuss optical properties of high-index dielectric nanoparticles, methods of their fabrication, and recent advances in practical applications, including the quantum source emission engineering, Fano resonances in all-dielectric nanoclusters, surface enhanced spectroscopy and sensing, coupled-resonator optical waveguides, metamaterials and metasurfaces, and nonlinear nanophotonics.

In this chapter, we give an overview of the various approaches for making tunable metamaterials and focus in more detail on several particular examples.

The following sections are included:

• Introduction
• Solitons in Metamaterials
• Bright Spatial Solitons in Hyperbolic Metamaterials
• Nonlinear Plasmonic Aspects of Metamaterials
• Acknowledgment
• References

Metamaterial catheter receivers for high-resolution internal magnetic resonance imaging (MRI) of the biliary system are described. The clinical goal, early detection and staging of bile duct cancer, is first introduced. Current approaches to diagnosis are then described, with an emphasis on MRI, and the advantages of internal imaging with an endoscopically-delivered receiver are highlighted. Magneto-inductive (MI) waveguides — linear arrays of magnetically-coupled L-C resonators — are proposed as a solution. MI waves and waveguides are reviewed, thin-film MI cables are introduced as a low-loss and stable format that can easily be mounted on a flexible catheter and the layouts needed for an inherently safe receiver are described. Experiments designed to demonstrate endoscopic compatibility, confirm safe operation and demonstrate high-resolution imaging are then presented. Frequency scaling is discussed, and experimental receivers are shown to out-perform surface coil arrays in vitro, over a limited field of view.

Microwave sensors based on the symmetry properties of transmission lines loaded with metamaterial resonators are reviewed in this chapter. In most microwave sensors based on resonant elements, the physical variable to be measured modifies the resonance frequency, phase or quality factor of the sensing resonant structure. In this chapter, a novel sensing principle, based on the disruption of symmetry, is studied. The proposed sensors are implemented by loading a transmission line either with symmetric resonators (typically, although not exclusively, resonant elements useful for the implementation of metamaterials) or with symmetric configurations of resonator pairs. In the unperturbed state, the whole structure (line and resonator/s) is symmetric, and it is designed to exhibit either an all-pass behavior (Type I sensors) or a single transmission zero (Type II sensors). Conversely, when symmetry is broken by the physical effect to be sensed (e.g. a linear or angular displacement, dielectric loading, etc.), a notch appears in Type I sensors, whereas a split-off (i.e. two transmission zeros) emerges in Type II sensors. Hence, Type I and Type II sensors can be designated as resonance-based and frequency-splitting sensors, respectively. These sensors are of special interest as comparators and are robust against changes in environmental conditions. Potential applications include contactless linear and angular displacement and velocity sensors, alignment sensors, permittivity sensors, etc.

The following section is included:

• Index