583 research outputs found
Omnidirectionally Bending to the Normal in epsilon-near-Zero Metamaterials
Contrary to conventional wisdom that light bends away from the normal at the
interface when it passes from high to low refractive index media, here we
demonstrate an exotic phenomenon that the direction of electromagnetic power
bends towards the normal when light is incident from arbitrary high refractive
index medium to \epsilon-near-zero metamaterial. Moreover, the direction of the
transmitted beam is close to the normal for all angles of incidence. In other
words, the electromagnetic power coming from different directions in air or
arbitrary high refractive index medium can be redirected to the direction
almost parallel to the normal upon entering the \epsilon-near-zero
metamaterial. This phenomenon is counterintuitive to the behavior described by
conventional Snell's law and resulted from the interplay between
\epsilon-near-zero and material loss. This property has potential applications
in communications to increase acceptance angle and energy delivery without
using optical lenses and mechanical gimbals
Resonant Transmission of Electromagnetic Fields through Subwavelength Zero- Slits
We theoretically investigate the transmission of electromagnetic radiation
through a metal plate with a zero- metamaterial slit, where the
permittivity tends towards zero over a given bandwidth. Our analytic results
demonstrate that the transmission coefficient can be substantial for a broad
range of slit geometries, including subwavelength widths that are many
wavelengths long. This novel resonant effect has features quite unlike the
Fabry-P\'{e}rot-like resonances that have been observed in conductors with deep
channels. We further reveal that these high impedance ultranarrow
zero- channels can have significantly {\it greater} transmission
compared to slits with no wave impedance difference across them
A Case of Mistaken Identity: Biomarkers for High Risk Premalignant Breast Lesions
Discusses projects to develop biomarkers to predict atypical hyperplasias that may progress to invasive breast cancer. This presentation is part of the retreat mini-symposium entitled: Biomarker Discovery and Targeted Therapeutics in Cancer
Magnetic field and temperature sensing with atomic-scale spin defects in silicon carbide
Quantum systems can provide outstanding performance in various sensing
applications, ranging from bioscience to nanotechnology. Atomic-scale defects
in silicon carbide are very attractive in this respect because of the
technological advantages of this material and favorable optical and radio
frequency spectral ranges to control these defects. We identified several,
separately addressable spin-3/2 centers in the same silicon carbide crystal,
which are immune to nonaxial strain fluctuations. Some of them are
characterized by nearly temperature independent axial crystal fields, making
these centers very attractive for vector magnetometry. Contrarily, the
zero-field splitting of another center exhibits a giant thermal shift of -1.1
MHz/K at room temperature, which can be used for thermometry applications. We
also discuss a synchronized composite clock exploiting spin centers with
different thermal response.Comment: 8 pages, 7 figure
Perfect Absorption in Ultrathin Epsilon-Near-Zero Metamaterials Induced by Fast-Wave Non-Radiative Modes
Above-light-line surface plasmon polaritons can arise at the interface
between a metal and epsilon-near-zero metamaterial. This unique feature induces
unusual fast-wave non-radiative modes in a epsilon-near-zero material/metal
bilayer. Excitation of this peculiar mode leads to wide-angle perfect
absorption in low-loss ultrathin metamaterials. The ratio of the perfect
absorption wavelength to the thickness of the epsilon-near-zero metamaterial
can be as high as 10^4; the electromagnetic energy can be confined in a layer
as thin as {\lambda}/10000. Unlike conventional fast-wave leaky modes, these
fast-wave non-radiative modes have quasi-static capacitive features that
naturally match with the space-wave field, and thus are easily accessible from
free space. The perfect absorption wavelength can be tuned from mid- to
far-infrared by tuning the epsilon = 0 wavelength while keeping the thickness
of the structure unchanged
Mode Bifurcation and Fold Points of Complex Dispersion Curves for the Metamaterial Goubau Line
In this paper the complex dispersion curves of the four lowest-order
transverse magnetic modes of a dielectric Goubau line () are
compared with those of a dispersive metamaterial Goubau line. The vastly
different dispersion curve structure for the metamaterial Goubau line is
characterized by unusual features such as mode bifurcation, complex fold
points, both proper and improper complex modes, and merging of complex and real
modes
Guided Modes of Elliptical Metamaterial Waveguides
The propagation of guided electromagnetic waves in open elliptical
metamaterial waveguide structures is investigated. The waveguide contains a
negative-index media core, where the permittivity, and permeability
are negative over a given bandwidth. The allowed mode spectrum for these
structures is numerically calculated by solving a dispersion relation that is
expressed in terms of Mathieu functions. By probing certain regions of
parameter space, we find the possibility exists to have extremely localized
waves that transmit along the surface of the waveguide
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