8,255 research outputs found
Unidirectional sub-diffraction waveguiding based on optical spin-orbit coupling in subwavelength plasmonic waveguides
Subwavelength plasmonic waveguides show the unique ability of strongly
localizing (down to the nanoscale) and guiding light. These structures are
intrinsically two-way optical communication channels, providing two opposite
light propagation directions. As a consequence, when light is coupled to these
planar integrated devices directly from the top (or bottom) surface using
strongly focused beams, it is equally shared into the two opposite propagation
directions. Here, we show that symmetry can be broken by using incident
circularly polarized light, on the basis of a spin-orbital angular momentum
transfer directly within waveguide bends. We predict that up to 94 \% of the
incoupled light is directed into a single propagation channel of a gap plasmon
waveguide. Unidirectional propagation of strongly localized optical energy, far
beyond the diffraction limit, becomes switchable by polarization, with no need
of intermediate nano-antennas/scatterers as light directors. This study may
open new perspectives in a large panel of scientific domains, such as
nanophotonic circuitry, routing and sorting, optical nanosensing, nano-optical
trapping and manipulation
Far-field mapping of the longitudinal magnetic and electric optical fields
In this letter, we demonstrate the experimental mapping of the longitudinal
magnetic and electric optical fields with a standard scanning microscope that
involves a high numerical aperture far-field objective. The imaging concept
relies upon the insertion of an azimuthal or a radial polarizer within the
detection path of the microscope which acts as an optical electromagnetic
filter aimed at transmitting selectively to the detector the signal from the
magnetic or electric longitudinal fields present in the detection volume,
respectively. The resulting system is thus versatile, non invasive, of high
resolution, and shows high detection efficiencies. Magnetic optical properties
of physical and biological micro and nano-structures may thus be revealed with
a far-field microscope
Predictability of Fixed-Job Priority Schedulers on Heterogeneous Multiprocessor Real-Time Systems
The multiprocessor Fixed-Job Priority (FJP) scheduling of real-time systems
is studied. An important property for the schedulability analysis, the
predictability (regardless to the execution times), is studied for
heterogeneous multiprocessor platforms. Our main contribution is to show that
any FJP schedulers are predictable on unrelated platforms. A convenient
consequence is the fact that any FJP schedulers are predictable on uniform
multiprocessors
Almost harmonic spinors
We show that any closed spin manifold not diffeomorphic to the two-sphere
admits a sequence of volume-one-Riemannian metrics for which the smallest
non-zero Dirac eigenvalue tends to zero. As an application, we compare the
Dirac spectrum with the conformal volume.Comment: minor modifications of the published versio
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