263 research outputs found
Transforming Fabry-Perot resonances into a Tamm mode
We propose a novel photonic structure composed of metal nanolayer, Bragg
mirror and metal nanolayer. The structure supports resonances that are
transitional between Fabry-Perot and Tamm modes. When the dielectric contrast
of the DBR is removed these modes are a pair of conventional Fabry-Perot
resonances. They spectrally merge into a Tamm mode at high contrast. Such
behavior differs from the results for structures supporting Tamm modes reported
earlier. The optical properties of the structure in the frequency range of the
DBR stop band, including highly beneficial 50% transmittivity through thick
structures, are determined by the introduced in the paper hybrid resonances.
The results can find a wide range of photonic applications.Comment: 5 pages, 4 figure
Abatement of Computational Issues Associated with Dark Modes in Optical Metamaterials
Optical fields in metamaterial nanostructures can be separated into bright
modes, whose dispersion is typically described by effective medium parameters,
and dark fluctuating fields. Such combination of propagating and evanescent
modes poses a serious numerical complication due to poorly conditioned systems
of equations for the amplitudes of the modes. We propose a numerical scheme
based on a transfer matrix approach, which resolves this issue for a parallel
plate metal-dielectric metamaterial, and demonstrate its effectiveness.Comment: 7 pages, 6 figure
Giant Surface Plasmon Induced Drag Effect (SPIDEr) in Metal Nanowires
Here, for the first time we predict a giant surface plasmon-induced drag
effect (SPIDEr), which exists under conditions of the extreme nanoplasmonic
confinement. Under realistic conditions, in nanowires, this giant SPIDEr
generates rectified THz potential differences up to 10 V and extremely strong
electric fields up to 10^5-10^6 V/cm. The SPIDEr is an ultrafast effect whose
bandwidth for nanometric wires is 20 THz. The giant SPIDEr opens up a new field
of ultraintense THz nanooptics with wide potential applications in
nanotechnology and nanoscience, including microelectronics,nanoplasmonics, and
biomedicine.Comment: 5 pages, 3 figure
Spontaneous emission of electric and magnetic dipoles in the vicinity of thin and thick metal
Strong modification of spontaneous emission of Eu3+ ions placed in close
vicinity to thin and thick gold and silver films was clearly demonstrated in a
microscope setup separately for electric and magnetic dipole transitions. We
have shown that the magnetic transition was very sensitive to the thickness of
the gold substrate and behaved distinctly different from the electric
transition. The observations were described theoretically based on the dyadic
Green's function approach for layered media and explained through modified
image models for the near and far-field emissions. We established that there
exists a "near-field event horizon", which demarcates the distance from the
metal at which the dipole emission is taken up exclusively in the near field.Comment: 11 pages, 7 figure
Toward Full Spatio-Temporal Control on the Nanoscale
We introduce an approach to implement full coherent control on nanometer
length scales. It is based on spatio-temporal modulation of the surface plasmon
polariton (SPP) fields at the thick edge of a nanowedge. The SPP wavepackets
propagating toward the sharp edge of this nanowedge are compressed and
adiabatically concentrated at a nanofocus, forming an ultrashort pulse of local
fields. The one-dimensional spatial profile and temporal waveform of this pulse
are completely coherently controlled.Comment: 4 pages, 3 figures Figures were replace
Optical control of scattering, absorption and lineshape in nanoparticles
We find exact conditions for the enhancement or suppression of internal and/or scattered fields in any smooth particle and the determination of their spatial distribution or angular momentum through the combination of simple fields. The incident fields can be generated by a single monochromatic or broad band light source, or by several sources, which may also be impurities embedded in the nanoparticle. We can design the lineshape of a particle introducing very narrow features in its spectral response
Energy transfer between a biological labelling dye and gold nanorods
We have demonstrated energy transfer between a biological labelling dye (Alexa Fluor 405) and gold nanorods experimentally and theoretically. The fluorescence lifetime imaging microscopy and density matrix method are used to study a hybrid system of dye and nanorods under one- and two-photon excitations. Energy transfer between dye and nanorods via the dipole–dipole interaction is found to cause a decrease in the fluorescence lifetime change. Enhanced energy transfer from dye to nanorods is measured in the presence of an increased density of nanorods. This study has potential applications in fluorescence lifetime-based intra-cellular sensing of bio-analytes as well as nuclear targeting cancer therap
Theory of Refraction, Ray-Wave Tilt, Hidden Momentum, and Apparent Topological Phases in Isotropy-Broken Materials based on Electromagnetism of Moving Media
One of the problems of physics arguably greater in stature than even
mathematical Hilberts problems is the mysterious nature of electromagnetic
momentum in materials. In this paper we show that the difference between the
Minkowski and Abraham momenta, which is composed of the Roentgen and Shockley
hidden momenta, is directly related to the phenomenon of refraction and the
tilt of rays from the wavefront propagation direction. We demonstrate that
individual electromagnetic waves with non-unit indices of refraction n appear
as quasistatic high-k waves to an observer in the proper frames of the waves.
When Lorentz transformed into the material rest frames these high-k waves are
Fresnel-Fizeau dragged from rest to their phase velocities and acquire
longitudinal hidden momentum and related refractive properties. On the material
level all electromagnetic waves belong to Fresnel wave surfaces topologically
classified according to hyperbolic phases by Durach and determined from the
electromagnetic material parameters. To moving observers, material parameters
appear modified, which leads not only to the alterations of Fresnel wave
surfaces, but even the topological classes of the materials may appear
differently in moving frames. We discuss the phenomenon of the electromagnetic
momentum tilt, defined as non-zero angle between Abraham and Minkowski momenta
or equivalently between the rays and the wavefront propagation direction. We
show that momentum tilt is only possible in isotropy-broken media, where E and
H fields can be longitudinally polarized in presence of electric and magnetic
bound charge waves. The momentum tilt can be understood as differential
aberration of rays and waves when observed in material rest frame.Comment: 21 pages, 6 figure
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