Electromagnetic transparency and slow light in an isotropic 3D optical metamaterial, due to Fano-like coupling of Mie resonances in excitonic nano-sphere inclusions

A three dimensional isotropic metamaterial is proposed and theoretically studied, which is composed of excitonic spherical nanoparticles in a dielectric host and exhibits electromagnetic transparency and slow light effects in optical regime. The approach is different from the conventional methods of realizing classical Electromagnetically Induced Transparency (EIT) or plasmon induced transparency effects, which are usually based on the interaction of dark and bright states of the medium plasmonic constituents. Instead, it is based on the Fano-like coupling of Mie resonances in the spherical inclusions, resulting from sharp and strong excitonic resonance of the particles. Using the Extended Maxwell Garnett effective medium approximation for calculating the effective electromagnetic parameters of the proposed metamaterial structure, it is shown that EIT-like effects can be produced, such as steep normal dispersion profiles within narrow transparency windows, resulting in high values of group index of refraction on the order of several thousands and figure of merit values around 10, near the excitonic resonance of the nanoparticle inclusions in UV region.     

Photonic crystal fibers with high and flattened dispersion

We investigate the dispersion property of space filling mode of photonic crystal structures and find a new type of dispersion—structure induced dispersion. By incorporating this new source of dispersion we designed PCF with large normal dispersion ~ 350 ps²/km. Our simulation indicates the dispersion of such fiber changes less than 3% in 1.4-1.7 μm wavelength range and we also show that our design is insensitive to the structure changes.     

Frequency characteristics of the dark and bright surface solitons at a nonlinear metamaterial interface

We investigate the generation and properties of dark and bright surface waves at the interface of a conventional medium and a metamaterial. It is shown that the stable dark and bright surface solitons can coexist even when the nonlinear Kerr coefficients of the two media are negative, completely different from those at the interface between two conventional media. Most importantly, both the dark and bright surface solitons exist only within a certain range of the effective refractive index of the metamaterial, greatly depending on the frequency of the electromagnetic wave propagating in it. Therefore, the generation conditions for surface solitons, and the properties of the generated surface solitons such as the peak positions and the intensity of the dark and bright surface solitons, can be controlled by adjusting the structure parameters of the metamaterial and/or the frequency of the electromagnetic wave.     

Low Refractive Metamaterials for Gain Enhancement of Horn Antenna

A flat metamaterials (MTMs) structure with low refractive index is proposed as a cover in a high-gain horn antenna configuration. The MTMs is composed of two-layer metallic grids and slices of foam. For the characterization of the MTMs, the low refraction property is studied and the effective refractive index n ≈ 0.08 (12.0 GHz) is retrieved. The antenna gain and the radiation pattern are calculated. Because of the electromagnetic wave congregating effect of the MTMs, the gain of the horn with MTMs greatly increases (about 4 dB from 11.8 GHz–12.8 GHz) when compared with the conventional type. We conducted the experiments to verify the simulation results. The idea has a good potential application to the feed design of parabolas.     

Modelling and Analysis of Ω-shaped Double Negative Material-assisted Microwave Sensor

A novel Ω-shaped double negative (DNG) material-assisted microwave sensor is presented, and modelled using a full wave electromagnetic commercial simulator CST. Simulating results show that the amplified evanescent wave is sensitive to the permittivity of dielectric material in the detecting zone. Meanwhile, mechanism of the evanescent wave amplification is explained. Comparing with conventional microwave resonant sensor, the Ω-shaped DNG materials-assisted microwave sensor allows for much higher sensitivity.      

Camouflage devices with simplified material parameters based on conformal transformation acoustics

Owing to the recent fascinating advances in transformation acoustics, it is possible to design the distribution of refractive index of attractive devices that can manipulate acoustic waves in almost any manner. Furthermore, if the transformation is conformal, the resultant devices can be made with ordinary isotropic materials instead of exotic anisotropic metamaterials. In this paper, we use conformal transformation acoustics to design camouflage devices with layered homogeneous structures, which can acoustically generate illusions of objects. We demonstrate two devices: one is called shifter that makes an object appearing at different places from the actual location; another is called combiner that makes two objects at separated locations looking like only one object.     

A Compact Zeroth‐Order Resonant Antenna on Vialess CPW Single Layer

In this letter, a novel zeroth‐order resonant (ZOR) antenna on vialess co‐planar waveguide (CPW) is proposed. It is based on a composite right/left‐handed CPW transmission line. To achieve a compact size, this antenna utilizes the ZOR condition, and its reactive parameters determine the resonant frequency. Each unit cell is composed of a metallic top patch and meander lines. Since it is realized on the CPW single layer, the proposed antenna has the benefits of being a compact size and easy to fabricate. The bandwidth of 6.8% and efficiency of 62% are experimentally achieved. Its bandwidth is enhanced compared with other ZOR antennas.     

Costas Soukoulis: An outline of his research work

I present a summary of Costas Soukoulis' research work and I point out the most significant of his contributions. His recent work on the Casimir interaction, in which I was involved, is summarized.     

Transformation Optics: From Classic Theory and Applications to its New Branches

In the modern world, the ability to manipulate and control electromagnetic waves has greatly changed people's lives. Novel optical and electromagnetic phenomena and devices will lead to new scientific trends and techniques in the future. The exploration of new theories of optical design and new materials for optical engineering has attracted great attention in recent years. Transformation optics (TO) provides a new way to design optical devices with extraordinary predesigned functions such as invisibility cloaks and electromagnetic wormholes. As the development of artificial electromagnetic media (e.g. metamaterials and metasurfaces) progresses, many of these novel optical devices designed by TO have been experimentally demonstrated and used in specific applications. Starting from the basic theory of transformation optics, we review its applications, extensions, new branches and recent developments in this paper.