113,113 research outputs found
Multi-plasmon absorption in graphene
We show that graphene possesses a strong nonlinear optical response in the
form of multi-plasmon absorption, with exciting implications in classical and
quantum nonlinear optics. Specifically, we predict that graphene nano-ribbons
can be used as saturable absorbers with low saturation intensity in the
far-infrared and terahertz spectrum. Moreover, we predict that two-plasmon
absorption and extreme localization of plasmon fields in graphene nano-disks
can lead to a plasmon blockade effect, in which a single quantized plasmon
strongly suppresses the possibility of exciting a second plasmon
High-sensing properties of magnetic plasmon resonances in double- and triple-rod structures
We numerically investigated the magnetic plasmon resonances in double-rod and
triple-rod structures (DRSs and TRSs, respectively) for sensing applications.
According to the equivalent circuit model, one magnetic plasmon mode was
induced in the DRS. Due to the hybridization effect, two magnetic plasmon modes
were obtained in the TRS. Compared with the electric plasmon resonance in a
single-rod structure (SRS), the electromagnetic fields near the DRS and TRS
were much more localized in the dielectric surrounding the structures at the
resonance wavelengths. This caused the magnetic plasmon resonance wavelengths
to become very sensitive to refractive index changes in the environment medium.
As a result, a large figure of merit that is much larger than the electric
plasmon modes of SRS could be obtained in the magnetic plasmon modes of DRS and
TRS. These magnetic plasmon mode properties enable the use of DRSs and TRSs as
sensing elements with remarkable performance
Graphene Terahertz Plasmon Oscillators
In this paper we propose and discuss coherent terahertz sources based on
charge density wave (plasmon) amplification in two dimensional graphene. The
coupling of the plasmons to interband electron-hole transitions in population
inverted graphene layers can lead to plasmon amplification through stimulated
emission. Plasmon gain values in graphene can be very large due to the small
group velocity of the plasmons and the strong confinement of the plasmon field
in the vicinity of the graphene layer. We present a transmission line model for
plasmon propagation in graphene that includes plasmon dissipation and plasmon
interband gain due to stimulated emission. Using this model, we discuss design
for terahertz plasmon oscillators and derive the threshold condition for
oscillation taking into account internal losses and also losses due to external
coupling. The large gain values available at terahertz frequencies in graphene
can lead to integrated oscillators that have dimensions in the 1-10 micron
range.Comment: To appear in IEEE Transactions on Nanotechnology (TNANO
Plasmon geometric phase and plasmon Hall shift
The collective plasmonic modes of a metal comprise a pattern of charge
density and tightly-bound electric fields that oscillate in lock-step to yield
enhanced light-matter interaction. Here we show that metals with non-zero Hall
conductivity host plasmons with a fine internal structure: they are
characterized by a current density configuration that sharply departs from that
of ordinary zero Hall conductivity metals. This non-trivial internal structure
dramatically enriches the dynamics of plasmon propagation, enabling plasmon
wavepackets to acquire geometric phases as they scatter. Strikingly, at
boundaries these phases accumulate allowing plasmon waves that reflect off to
experience a non-reciprocal parallel shift along the boundary displacing the
incident and reflected plasmon trajectories. This plasmon Hall shift, tunable
by Hall conductivity as well as plasmon wavelength, displays the chirality of
the plasmon's current distribution and can be probed by near-field photonics
techniques. Anomalous plasmon dynamics provide a real-space window into the
inner structure of plasmon bands, as well as new means for directing plasmonic
beams
Quantum emitters coupled to surface plasmons of a nano-wire: A Green function approach
We investigate a system consisting of a single, as well as two emitters
strongly coupled to surface plasmon modes of a nano-wire using a Green function
approach. Explicit expressions are derived for the spontaneous decay rate into
the plasmon modes and for the atom-plasmon coupling as well as a
plasmon-mediated atom-atom coupling. Phenomena due to the presence of losses in
the metal are discussed. In case of two atoms, we observe Dicke sub- and
superradiance resulting from their plasmon-mediated interaction. Based on this
phenomenon, we propose a scheme for a deterministic two-qubit quantum gate. We
also discuss a possible realization of interesting many-body Hamiltonians, such
as the spin-boson model, using strong emitter-plasmon coupling.Comment: 12 pages, 16 figure
Plasmon Resonances in Nanoparticles, Their Applications to Magnetics and Relation to the Riemann Hypothesis
The review of the mathematical treatment of plasmon resonances as an
eigenvalue problem for specific boundary integral equations is presented and
general properties of plasmon spectrum are outlined. Promising applications of
plasmon resonances to magnetics are described. Interesting relation of
eigenvalue treatment of plasmon resonances to the Riemann hypothesis is
discussed.Comment: 10 pages; misprints corrected, some explanations added. Physica B
(2011
- …