Electromagnetic metamaterials

Super-resolution imaging using a three-dimensional metamaterials nanolens

by Evin Gultepe

Published in Applied Physics Letters, 2010  http://link.aip.org/link/?APPLAB/96/023114/1

Super-resolution imaging beyond Abbe's diffraction limit can be achieved by utilizing an optical medium or... more Super-resolution imaging beyond Abbe's diffraction limit can be achieved by utilizing an optical medium or “metamaterial” that can either amplify or transport the decaying near-field evanescent waves that carry subwavelength features of objects. Earlier approaches at optical frequencies mostly utilized the amplification of evanescent waves in thin metallic films or metal-dielectric multilayers, but were restricted to very small thicknesses (<<lambda, wavelength) and accordingly short object-image distances, due to losses in the material. Here, we present an experimental demonstration of super-resolution imaging by a low-loss three-dimensional metamaterial nanolens consisting of aligned gold nanowires embedded in a porous alumina matrix. This composite medium possesses strongly anisotropic optical properties with negative permittivity in the nanowire axis direction, which enables the transport of both far-field and near-field components with low-loss over significant distances (>6 lambda), and over a broad spectral range. We demonstrate the imaging of large objects, having subwavelength features, with a resolution of at least lambda/4 at near-infrared wavelengths. The results are in good agreement with a theoretical model of wave propagation in anisotropic media.

FDTD analysis of coupled microstrip lines separated by a DNG slab

by Debdeep Sarkar

Effects of a DNG slab sandwiched between two coupled microstrip line on forward and backward coupling are reported in... more Effects of a DNG slab sandwiched between two coupled microstrip line on forward and backward coupling are reported in this paper. For analysis of the problem, an efficient hybrid formulation of FDTD is proposed that uses Z-transform for Drude model to represent negative permittivity and auxiliary differential equation for Lorentz model in modeling
negative permeability.

Compact Two Pole Bandpass Filter Implemented Using Via-free Composite Right/Left Handed Transmission Line with Radial Stubs

by Raghvendra Kumar Chaudhary

41th European Microwave Conference (EuMC), pp. 571 - 574, 9 Oct. - 14 Oct., 2011, Manchester, United Kingdom (UK).

This paper suggests the design of a compact two-pole bandpass filter based on the via-free composite right/left-handed... more This paper suggests the design of a compact two-pole bandpass filter based on the via-free composite right/left-handed (CRLH) metamaterial transmission line (TL) structure with radial stubs. The BPF design uses these sub-wavelength resonators (CRLH unit cells) along with admittance inverters to control the coupling. It is found that the suggested method enables up to 70% size reduction from the conventional filters such as the parallel coupled type which is designed on the basis of the half-wavelength resonance. The proposed technique is validated by experimental results.

Planar Db Boundary Placed in a Chiral and Chiral Nihility Metamaterial

by Aftab Naqvi

Domain compression via anisotropic metamaterials designed by coordinate transformations

by Ozlem Ozgun

Form-Invariance of Maxwell's Equations in Waveguide Cross-Section Transformations

by Ozlem Ozgun

Efficient finite element solution of low‐frequency scattering problems via anisotropic metamaterial layers

by Ozlem Ozgun

Utilization of anisotropic metamaterial layers in waveguide miniaturization and transitions

by Ozlem Ozgun

Electromagnetic metamorphosis: Reshaping scatterers via conformal anisotropic metamaterial coatings

by Ozlem Ozgun

Reconfigurable gradient index using VO2 memory metamaterials

by Brian Chapler

M.D. Goldflam, T. Driscoll, B .Chapler, O. Khatib, N. Marie Jokerst, S. Palit, D.R. Smith, Bong-Jun Kim, Giwan Seo, Hyun-Tak Kim, M. Di Ventra, and D.N. Basov

We demonstrate tuning of a metamaterial device that incorporates a form of spatial gradient control. Electrical tuning... more We demonstrate tuning of a metamaterial device that incorporates a form of spatial gradient control. Electrical tuning of the metamaterial is achieved through a vanadium dioxide layer which interacts with an array of split ring resonators. We achieved a spatial gradient in the magnitude of permittivity, writeable using a single transient electrical pulse. This induced gradient in our devices observed on spatial scales on the order of one wavelength at 1 THz. Thus, we show the viability of elements for use in future devices with potential applications in beam forming and communications.

Active Maxwell-Garnett composite with the unit refractive index

by Sergey Moiseev

Published in: Physica B: Condensed Matter, 2010, Volume 405, Issue 14, Pages 3042-3045.

'Reports on physics findings from Russian Academy of Science provide new insights' dedicated to S.Moiseev’s work was published by News of Science (News of Science, August 29, 2010 - http://www.verticalnews.com/premium_newsletters/News-of-Science/2010-08-29/60737NOS.html) and Physics Week (Physics Week, August 24, 2010 - http://www.verticalnews.com/premium_newsletters/Physics-Week/2010-08-24/60737PH.html).

Optical properties of a three-dimensional composite medium consisting of an amplifying matrix with inclusion of silver... more Optical properties of a three-dimensional composite medium consisting of an amplifying matrix with inclusion of silver nanoparticles of various shapes are investigated theoretically. Behaviour of the amplification coefficient of active component required for compensating energy dissipation at metal inclusions is studied. Results of exact electrodynamical calculations of conditions for obtaining the unit refractive index and that performed using electrostatic approximation (Maxwell-Garnett approach) are compared

On the problems of transparency of metal-dielectric composite media with dissipative and amplifying components

by Sergey Moiseev

Co-authored with E. A. Pashinina, S. V. Sukhov.
Published in: Quantum Electron., 2007, V.37, N. 5, pp. 446-452.

Two models of metal-dielectric composite media are used to study the optical properties of their active (amplifying)... more Two models of metal-dielectric composite media are used to study the optical properties of their active (amplifying) components under conditions of compensation for the absorption of external electromagnetic radiation appearing due to the presence of metal inclusions. It is shown that the electrostatic approximation for describing the concentrated composite media (a metal nanosphere in a dielectric shell) and bulk composite media (a system of metal nanocylinders in a dielectric matrix) can be applied only in a small range of geometrical and optical parameters. Precise electrodynamic calculations give much smaller gains in the active component required to compensate for absorption, which can be useful for developing 'transparent' composite materials with unique optical properties or 'invisible' composite particles.