54 research outputs found
Broadband light coupling to dielectric slot waveguides with tapered plasmonic nanoantennas
We propose and theoretically verify an efficient mechanism of broadband
coupling between incident light and on-chip dielectric slot waveguide by
employing a tapered plasmonic nanoantenna. Nanoantenna receives free space
radiation and couples it to a dielectric slot waveguide with the efficiency of
up to 20% in a broad spectral range, having a small footprint as compared with
the currently used narrowband dielectric grating couplers. We argue that the
frequency selective properties of such nanoantennas also allow for using them
as ultrasmall on-chip multiplexer/demultiplexer devices
Tuneable plasmonics enabled by capillary oscillations of liquid-metal nanodroplets
Plasmonics allows manipulating light at the nanoscale, but has limitations
due to the static nature of nanostructures and lack of tuneability. We propose
and theoretically analyse a room-temperature liquid-metal nanodroplet that
changes its shape, and therefore tunes the plasmon resonance frequency, due to
capillary oscillations. We show the possibility to tune the capillary
oscillation frequency of the nanodroplet and to drive the oscillations
electrically or mechanically. Employed as a tuneable nanoantenna, the
nanodroplet may find applications in sensors, imaging, microscopy, and
medicine
Transverse magneto-optical Kerr effect in subwavelength dielectric gratings
We demonstrate theoretically a large transverse magneto-optical Kerr effect
(TMOKE) in subwavelength gratings consisting of alternating magneto-insulating
and nonmagnetic dielectric nanostripes. The reflectivity of the grating reaches
at the frequencies corresponding to the maximum of the TMOKE response.
The combination of a large TMOKE response and high reflectivity is important
for applications in D imaging, magneto-optical data storage, and magnonics
Rigorous numerical study of strong microwave photon-magnon coupling in all-dielectric magnetic multilayers
We demonstrate theoretically a strong local enhancement of the intensity of
the in-plane microwave magnetic field in multilayered structures made from a
magneto-insulating yttrium iron garnet (YIG) layer sandwiched between two
non-magnetic layers with a high dielectric constant matching that of YIG. The
enhancement is predicted for the excitation regime when the microwave magnetic
field is induced inside the multilayer by the transducer of a stripline
Broadband Ferromagnetic Resonance (BFMR) setup. By means of a rigorous
numerical solution of the Landau-Lifshitz-Gilbert equation consistently with
the Maxwell's equations, we investigate the magnetisation dynamics in the
multilayer. We reveal a strong photon-magnon coupling, which manifests itself
as anti-crossing of the ferromagnetic resonance (FMR) magnon mode supported by
the YIG layer and the electromagnetic resonance mode supported by the whole
multilayered structure. The frequency of the magnon mode depends on the
external static magnetic field, which in our case is applied tangentially to
the multilayer in the direction perpendicular to the microwave magnetic field
induced by the stripline of the BFMR setup. The frequency of the
electromagnetic mode is independent of the static magnetic field. Consequently,
the predicted photon-magnon coupling is sensitive to the applied magnetic field
and thus can be used in magnetically tuneable metamaterials based on
simultaneously negative permittivity and permeability achievable thanks to the
YIG layer. We also suggest that the predicted photon-magnon coupling may find
applications in microwave quantum information systems
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