230 research outputs found
Gap plasmon polariton structure for very efficient micro to nano scale interfacing
The seamless transition between micro-scale photonics and nano-scale
plasmonics requires the mitigation between different waveguiding mechanisms as
well as between few orders of magnitude in the field lateral size, down to a
small fraction of a wavelength. By exploiting gap plasmon polariton waves both
at the micro and nano scale, very high power transfer efficiency (>60%) can be
achieved using an ultrashort (few microns) non adiabatic tapered gap plasmon
waveguide. Same mechanism may be used to harvest impinging light waves and
direct them into a nano hole or slit, to exhibit an anomalous transmission -
without the conventional periodic structures. The special interplay of
plasmonic and oscillating modes is analyzed.Comment: Submitted to PRL. Part of the work was presented at IPRA-2005
conference, paper JWA
Tooth-shaped plasmonic waveguide filters with nanometeric sizes
A novel nanometeric plasmonic filter in a tooth-shaped Metal-Insulator-Metal
waveguide is proposed and demonstrated numerically. An analytic model based on
the scattering matrix method is given. The result reveals that the single
tooth-shaped filter has a wavelength filtering characteristic and an
ultra-compact size in the length of a few hundred nanometers, compared to
grating-like SPPs filters. Both analytic and simulation results show that the
wavelength of the trough of the transmission has linear and nonlinear
relationships with the tooth depth and the tooth width, respectively. The
waveguide filter could be utilized to develop ultra-compact photonic filters
for high integration.Comment: 16 pages, 5 figure
Numerical Modeling of a Teeth-shaped Nano-plasmonic Waveguide Filter
In this paper, tooth-shaped and multiple-teeth-shaped plasmonic filters in
the metal-insulator-metal (MIM) waveguides are demonstrated numerically. By
introducing a three-port waveguide splitter, a modified model based on the
multiple-beam-interference and the scattering matrix is given. The ransmittance
spectrum as a function of teeth width, depth, period and period number are
respectively addressed. The result shows the new structure not only performs
the filtering function as well as MIM grating-like structures, but also is of
submicrometer size for ultra-high integration and relatively easy fabrication.Comment: 21pages, 7 figure
Ring-Like Solitons in Plasmonic Fiber Waveguide Composed of Metal-Dielectric Multilayers
We design a plasmonic fiber waveguide (PFW) composed of coaxial cylindrical
metal-dielectric multilayers in nanoscale, and constitute the corresponding
dynamical equations describing the modes of propagation in the PFW with the
Kerr nonlinearity in the dielectric layers. The physics is connected to the
discrete matrix nonlinear Schr\"{o}dinger equations, from which the highly
confined ring-like solitons in scale of subwavelength are found both for the
visible light and the near-infrared light in the self-defocusing condition.
Moreover, the confinement could be further improved when increasing the
intensity of the input light due to the cylindrical symmetry of the PFW, which
means both the width and the radius of the ring are reduced.Comment: 4 figures, submitte
A comparative study of semiconductor-based plasmonic metamaterials
Recent metamaterial (MM) research faces several problems when using
metal-based plasmonic components as building blocks for MMs. The use of
conventional metals for MMs is limited by several factors: metals such as gold
and silver have high losses in the visible and near-infrared (NIR) ranges and
very large negative real permittivity values, and in addition, their optical
properties cannot be tuned. These issues that put severe constraints on the
device applications of MMs could be overcome if semiconductors are used as
plasmonic materials instead of metals. Heavily doped, wide bandgap oxide
semiconductors could exhibit both a small negative real permittivity and
relatively small losses in the NIR. Heavily doped oxides of zinc and indium
were already reported to be good, low loss alternatives to metals in the NIR
range. Here, we consider these transparent conducting oxides (TCOs) as
alternative plasmonic materials for many specific applications ranging from
surface-plasmon-polariton waveguides to MMs with hyperbolic dispersion and
epsilon-near-zero (ENZ) materials. We show that TCOs outperform conventional
metals for ENZ and other MM-applications in the NIR.Comment: 16 pages, 7 figure
Scattering mechanism in a step-modulated subwavelength metal slit: a multi-mode multi-reflection analysis
In this paper, the scattering/transmission inside a step-modulated
subwavelength metal slit is investigated in detail. We firstly investigate the
scattering in a junction structure by two types of structural changes. The
variation of transmission and reflection coefficients depending on structural
parameters are analyzed. Then a multi-mode multi-reflection model based on ray
theory is proposed to illustrate the transmission in the step-modulated slit
explicitly. The key parts of this model are the multi-mode excitation and the
superposition procedure of the scatterings from all possible modes, which
represent the interference and energy transfer happened at interfaces. The
method we use is an improved modal expansion method (MEM), which is a more
practical and efficient version compared with the previous one [Opt. Express
19, 10073 (2011)]. In addition, some commonly used methods, FDTD, scattering
matrix method, and improved characteristic impedance method, are compared with
MEM to highlight the preciseness of these methods.Comment: 25 pages, 9 figure
Plasmonic mode converter for controlling optical impedance and nanoscale light-matter interaction
To enable multiple functions of plasmonic nanocircuits, it is of key
importance to control the propagation properties and the modal distribution of
the guided optical modes such that their impedance matches to that of nearby
quantum systems and desired light-matter interaction can be achieved. Here, we
present efficient mode converters for manipulating guided modes on a plasmonic
two-wire transmission line. The mode conversion is achieved through varying the
path length, wire cross section and the surrounding index of refraction.
Instead of pure optical interference, strong near-field coupling of surface
plasmons results in great momentum splitting and modal profile variation. We
theoretically demonstrate control over nanoantenna radiation and discuss the
possibility to enhance nanoscale light-matter interaction. The proposed
converter may find applications in surface plasmon amplification, index sensing
and enhanced nanoscale spectroscopy.Comment: 14 pages, 6 figure
Titanium nitride as a plasmonic material for visible and near-infrared wavelengths
The search for alternative plasmonic materials with improved optical properties, easier fabrication and integration capabilities over those of the traditional materials such as silver and gold could ultimately lead to real-life applications for plasmonics and metamaterials. In this work, we show that titanium nitride could perform as an alternative plasmonic material in the visible and near-infrared regions. We demonstrate the excitation of surface-plasmon-polaritons on titanium nitride thin films and discuss the performance of various plasmonic and metamaterial structures with titanium nitride as the plasmonic component. We also show that titanium nitride could provide performance that is comparable to that of gold for plasmonic applications and can significantly outperform gold and silver for transformation-optics and some metamaterial applications in the visible and near-infrared regions. (C) 2012 Optical Society of Americ
Surface Plasmon mediated near-field imaging and optical addressing in nanoscience
We present an overview of recent progress in plasmonics. We focus our study
on the observation and excitation of surface plasmon polaritons (SPPs) with
optical near-field microscopy. We discuss in particular recent applications of
photon scanning tunnelling microscope (PSTM) for imaging of SPP propagating in
metal and dielectric wave guides. We show how near-field scanning optical
microscopy (NSOM) can be used to optically and actively address remotely
nano-objects such as quantum dots. Additionally we compare results obtained
with near-field microscopy to those obtained with other optical far-field
methods of analysis such as leakage radiation microscopy (LRM)
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