264 research outputs found
Mie plasmons: modes volumes, quality factors and coupling strengths (Purcell factor) to a dipolar emitter
Using either quasi-static approximation or exact Mie expansion, we
characterize the localized surface plasmons supported by a metallic spherical
nanoparticle. We estimate the quality factor and define the effective
volume of the mode in a such a way that coupling strength with a
neighbouring dipolar emitter is proportional to the ratio (Purcell
factor). The role of Joule losses, far-field scattering and mode confinement in
the coupling mechanism are introduced and discussed with simple physical
understanding, with particular attention paid to energy conservation.Comment: (in press) International Journal of Optics (2011
Purcell factor for point-like dipolar emitter coupling to 2D-plasmonic waveguides
We theoretically investigate the spontaneous emission of a point--like
dipolar emitter located near a two--dimensional (2D) plasmonic waveguide of
arbitrary form. We invoke an explicite link with the density of modes of the
waveguide describing the electromagnetic channels into which the emitter can
couple. We obtain a closed form expression for the coupling to propagative
plasmon, extending thus the Purcell factor to plasmonic configurations.
Radiative and non-radiative contributions to the spontaneous emission are also
discussed in details
Meta-material photonic funnels for sub-diffraction light compression and propagation
We present waveguides with photonic crystal cores, supporting energy
propagation in subwavelength regions with a mode structure similar to that in
telecom fibers. We design meta-materials for near-, mid-, and far-IR
frequencies, and demonstrate efficient energy transfer to and from regions
smaller than 1/25-th of the wavelength. Both positive- and negative-refractive
index light transmissions are shown. Our approach, although demonstrated here
in circular waveguides for some specific frequencies, is easily scalable from
optical to IR to THz frequency ranges, and can be realized in a variety of
waveguide geometries. Our design may be used for ultra high-density energy
focusing, nm-resolution sensing, near-field microscopy, and high-speed
all-optical computing.Comment: 4 pages, 3 figures, texify read
Near-field properties of plasmonic nanostructures with high aspect ratio
Using the Green's dyad technique based on cuboidal meshing, we compute the
electromagnetic field scattered by metal nanorods with high aspect ratio. We
investigate the effect of the meshing shape on the numerical simulations. We
observe that discretizing the object with cells with aspect ratios similar to
the object's aspect ratio improves the computations, without degrading the
convergency. We also compare our numerical simulations to finite element method
and discuss further possible improvements
Pre-determining the location of electromigrated gaps by nonlinear optical imaging
In this paper we describe a nonlinear imaging method employed to spatially
map the occurrence of constrictions occurring on an electrically-stressed gold
nanowire. The approach consists at measuring the influence of a tightly focused
ultrafast pulsed laser on the electronic transport in the nanowire. We found
that structural defects distributed along the nanowire are efficient nonlinear
optical sources of radiation and that the differential conductance is
significantly decreased when the laser is incident on such electrically-induced
morphological changes. This imaging technique is applied to pre-determined the
location of the electrical failure before it occurs.Comment: 3 figure
Interference of surface plasmon polaritions controlled by the phase of incident light
Interference patterns of surface plasmon polaritons(SPPs) are observed in the
extraordinary optical transmission through subwavelength holes in optically
thick metal plate. It is found that the phase of incident light can be
transferred to SPPs. We can control the destructive and constructive
interference of SPPs by modulating the relative phase between two incident
beams. Using a slightly displaced Mach-Zehnder interferometer, we also observe
a SPPs interference pattern composed of bright and dark stripes.Comment: 3pages,5figure
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