1,435 research outputs found
A near-field study on the transition from localized to propagating plasmons on 2D nano-wedges
In this manuscript we report on a near-feld study of two-dimensional
plasmonic gold nano-wedges using electron energy loss spectroscopy in
combination with scanning transmission electron microscopy, as well as
discontinuous Galerkin time-domain computations. With increasing nano-wedge
size, we observe a transition from localized surface plasmons on small
nano-wedges to non-resonant propagating surface plasmon polaritons on large
nano-wedges. Furthermore we demonstrate that nano-wedges with a groove cut can
support localized as well as propagating plasmons in the same energy range
Observation of topological transport quantization by dissipation in fast Thouless pumps
Quantized dynamics is essential for natural processes and technological
applications alike. The work of Thouless on quantized particle transport in
slowly varying potentials (Thouless pumping) has played a key role in
understanding that such quantization may be caused not only by discrete
eigenvalues of a quantum system, but also by invariants associated with the
nontrivial topology of the Hamiltonian parameter space. Since its discovery,
quantized Thouless pumping has been believed to be restricted to the limit of
slow driving, a fundamental obstacle for experimental applications. Here, we
introduce non-Hermitian Floquet engineering as a new concept to overcome this
problem. We predict that a topological band structure and associated quantized
transport can be restored at driving frequencies as large as the system's band
gap. The underlying mechanism is suppression of non-adiabatic transitions by
tailored, time-periodic dissipation. We confirm the theoretical predictions by
experiments on topological transport quantization in plasmonic waveguide
arrays
Observation of a topological edge state stabilized by dissipation
Robust states emerging at the boundary of a system constitute a hallmark for
topological band structures. Other than in closed systems, topologically
protected states can occur even in systems with a trivial band structure, if
exposed to suitably modulated losses. Here, we study the dissipation-induced
emergence of a topological band structure in a non-Hermitian one-dimensional
lattice system, realized by arrays of plasmonic waveguides with tailored loss.
We obtain direct evidence for a topological edge state that resides in the
center of the band gap. By tuning dissipation and hopping, the formation and
breakdown of an interface state between topologically distinct regions is
demonstrated.Comment: 9 pages, 6 figure
Manipulation of Airy surface plasmon beams
We demonstrate experimentally the manipulation of Airy surface plasmon beams in a linear potential. For this purpose, we fabricate dielectric-loaded plasmonic structures with a graded refractive index by negative-tone gray-scale electron beam lithography. Using such carefully engineered potentials, we show that the bending of an Airy surface plasmon beam can be fully reversed by the potential.We acknowledge support from the Australian Research
Council and the Australian National Computational
Infrastructure
Direct laser-written optomechanical membranes in fiber Fabry-Perot cavities
Integrated micro and nanophotonic optomechanical experiments enable the
manipulation of mechanical resonators on the single phonon level. Interfacing
these structures requires elaborate techniques limited in tunability,
flexibility, and scaling towards multi-mode systems. Here, we demonstrate a
cavity optomechanical experiment using 3D-laser-written polymer membranes
inside fiber Fabry-Perot cavities. Vacuum coupling strengths of ~ 30 kHz to the
fundamental megahertz mechanical mode are reached. We observe optomechanical
spring tuning of the mechanical resonator by tens of kHz exceeding its
linewidth at cryogenic temperatures. The extreme flexibility of the laser
writing process allows for a direct integration of the membrane into the
microscopic cavity. The direct fiber coupling, its scaling capabilities to
coupled resonator systems, and the potential implementation of dissipation
dilution structures and integration of electrodes make it a promising platform
for fiber-tip integrated accelerometers, optomechanically tunable multi-mode
mechanical systems, or directly fiber-coupled systems for microwave to optics
conversion.Comment: 10 pages, 5 figure
Negative-index bi-anisotropic photonic metamaterial fabricated by direct laser writing and silver shadow evaporation
We present the blueprint for a novel negative-index metamaterial. This
structure is fabricated via three-dimensional two-photon direct laser writing
and silver shadow evaporation. The comparison of measured linear optical
spectra with theory shows good agreement and reveals a negative real part of
the refractive index at around 3.85 micrometer wavelength - despite the fact
that the metamaterial structure is bi-anisotropic due to the lack of inversion
symmetry along its surface normal.Comment: 8 pages, 3 figure
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