273 research outputs found
Enhanced surface plasmon polariton propagation induced by active dielectrics
We present numerical simulations for the propagation of surface plasmon
polaritons in a dielectric-metal-dielectric waveguide using COMSOL multiphysics
software. We show that the use of an active dielectric with gain that
compensates metal absorption losses enhances substantially plasmon propagation.
Furthermore, the introduction of the active material induces, for a specific
gain value, a root in the imaginary part of the propagation constant leading to
infinite propagation of the surface plasmon. The computational approaches
analyzed in this work can be used to define and tune the optimal conditions for
surface plasmon polariton amplification and propagation
Manipulating polarized light with a planar slab of Black Phosphorus
Wave polarization contains valuable information for electromagnetic signal
processing and the ability to manipulate it can be extremely useful in photonic
devices. In this work, we propose designs comprised of one of the emerging and
interesting two-dimensional media: Black Phosphorus. Due to substantial
in-plane anisotropy, a single slab of Black Phosphorus can be very efficient
for manipulating the polarization state of electromagnetic waves. We
investigate Black Phosphorus slabs that filter the fields along one direction,
or polarization axis rotation, or convert linear polarization to circular.
These slabs can be employed as components in numerous mid-IR integrated
devices
Epsilon-near-zero behavior from plasmonic Dirac point: Theory and realization using two-dimensional materials
The electromagnetic response of a two-dimensional metal embedded in a periodic array of a dielectric host
can give rise to a plasmonic Dirac point that emulates epsilon-near-zero (ENZ) behavior. This theoretical result is
extremely sensitive to structural features like periodicity of the dielectricmedium and thickness imperfections.We
propose that such a device can actually be realized by using graphene as the two-dimensional metal and materials
like the layered semiconducting transition-metal dichalcogenides or hexagonal boron nitride as the dielectric
host. We propose a systematic approach, in terms of design characteristics, for constructing metamaterials with
linear, elliptical, and hyperbolic dispersion relations which produce ENZ behavior, normal or negative diffractio
Emergence and dynamical properties of stochastic branching in the electronic flows of disordered Dirac solids
Graphene as well as more generally Dirac solids constitute two dimensional
materials where the electronic flow is ultra relativistic. When a Dirac solid
is deposited on a different substrate surface with roughness, a local random
potential develops through an inhomogeneous charge impurity distribution. This
external potential affects profoundly the charge flow and induces a chaotic
pattern of current branches that develops through focusing and defocusing
effects produced by the randomness of the surface. An additional bias voltage
may be used to tune the branching pattern of the charge carrier currents. We
employ analytical and numerical techniques in order to investigate the onset
and the statistical properties of carrier branches in Dirac solids. We find a
specific scaling-type relationship that connects the physical scale for the
occurrence of branches with the characteristic medium properties, such as
disorder and bias field. We use numerics to test and verify the theoretical
prediction as well as a perturbative approach that gives a clear indication of
the regime of validity of the approach. This work is relevant to device
applications and may be tested experimentally
Epsilon-near-zero behavior from plasmonic Dirac point: Theory and realization using two-dimensional materials
The electromagnetic response of a two-dimensional metal embedded in a periodic array of a dielectric host
can give rise to a plasmonic Dirac point that emulates epsilon-near-zero (ENZ) behavior. This theoretical result is
extremely sensitive to structural features like periodicity of the dielectricmedium and thickness imperfections.We
propose that such a device can actually be realized by using graphene as the two-dimensional metal and materials
like the layered semiconducting transition-metal dichalcogenides or hexagonal boron nitride as the dielectric
host. We propose a systematic approach, in terms of design characteristics, for constructing metamaterials with
linear, elliptical, and hyperbolic dispersion relations which produce ENZ behavior, normal or negative diffractio
- …