50 research outputs found
A low-loss photonic silica nanofiber for higher-order modes
Optical nanofibers confine light to subwavelength scales, and are of interest
for the design, integration, and interconnection of nanophotonic devices. Here
we demonstrate high transmission (> 97%) of the first family of excited modes
through a 350 nm radius fiber, by appropriate choice of the fiber and precise
control of the taper geometry. We can design the nanofibers so that these modes
propagate with most of their energy outside the waist region. We also present
an optical setup for selectively launching these modes with less than 1%
fundamental mode contamination. Our experimental results are in good agreement
with simulations of the propagation. Multimode optical nanofibers expand the
photonic toolbox, and may aid in the realization of a fully integrated
nanoscale device for communication science, laser science or other sensing
applications.Comment: 12 pages, 5 figures, movies available onlin
Ultrahigh Transmission Optical Nanofibers
We present a procedure for reproducibly fabricating ultrahigh transmission
optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode
transmissions of 99.95 0.02%, which represents a loss from tapering of
2.6 10 dB/mm when normalized to the entire stretch. When
controllably launching the next family of higher-order modes on a fiber with
195 mm stretch, we achieve a transmission of 97.8 2.8%, which has a loss
from tapering of 5.0 10 dB/mm when normalized to the
entire stretch. Our pulling and transfer procedures allow us to fabricate
optical nanofibers that transmit more than 400 mW in high vacuum conditions.
These results, published as parameters in our previous work, present an
improvement of two orders of magnitude less loss for the fundamental mode and
an increase in transmission of more than 300% for higher-order modes, when
following the protocols detailed in this paper. We extract from the
transmission during the pull, the only reported spectrogram of a fundamental
mode launch that does not include excitation to asymmetric modes; in stark
contrast to a pull in which our cleaning protocol is not followed. These
results depend critically on the pre-pull cleanliness and when properly
following our pulling protocols are in excellent agreement with simulations.Comment: 32 pages, 10 figures, accepted to AIP Advance
Nonlinear Polariton Fluids in a Flatband Reveal Discrete Gap Solitons
Phase frustration in periodic lattices is responsible for the formation of
dispersionless flat bands. The absence of any kinetic energy scale makes flat
band physics critically sensitive to perturbations and interactions. We report
here on the experimental investigation of the nonlinear dynamics of cavity
polaritons in the gapped flat band of a one-dimensional Lieb lattice. We
observe the formation of gap solitons with quantized size and very abrupt
edges, signature of the frozen propagation of switching fronts. This type of
gap solitons belongs to the class of truncated Bloch waves, and had only been
observed in closed systems up to now. Here the driven-dissipative character of
the system gives rise to a complex multistability of the nonlinear domains
generated in the flat band. These results open up interesting perspective
regarding more complex 2D lattices and the generation of correlated photon
phases.Comment: 6 pages, 4 figures + supplemental material (6 pages, 6 figures
Measuring topological invariants in polaritonic graphene
Topological materials rely on engineering global properties of their bulk
energy bands called topological invariants. These invariants, usually defined
over the entire Brillouin zone, are related to the existence of protected edge
states. However, for an important class of Hamiltonians corresponding to 2D
lattices with time-reversal and chiral symmetry (e.g. graphene), the existence
of edge states is linked to invariants that are not defined over the full 2D
Brillouin zone, but on reduced 1D sub-spaces. Here, we demonstrate a novel
scheme based on a combined real- and momentum-space measurement to directly
access these 1D topological invariants in lattices of semiconductor
microcavities confining exciton-polaritons. We extract these invariants in
arrays emulating the physics of regular and critically compressed graphene
sucht that Dirac cones have merged. Our scheme provides a direct evidence of
the bulk-edge correspondence in these systems, and opens the door to the
exploration of more complex topological effects, for example involving disorder
and interactions.Comment: Suppl. Mat. added; improved data/error analysi
Reconfigurable photon localization by coherent drive and dissipation in photonic lattices
7 pags., 4 figs.The engineering of localized modes in photonic structures is one of the main targets of modern photonics. An efficient strategy to design these modes is to use the interplay of constructive and destructive interference in periodic photonic lattices. This mechanism is at the origin of the defect modes in photonic bandgaps, bound states in the continuum, and compact localized states in flat bands. Here, we show that in lattices of lossy resonators, the addition of external optical drives with a controlled phase enlarges the possibilities of manipulating interference effects and allows for the design of novel types of localized modes. Using a honeycomb lattice of coupled micropillars resonantly driven with several laser spots at energies within its photonic bands, we demonstrate the localization of light in at-will geometries down to a single site. These localized modes are fully reconfigurable and have the potentiality of enhancing nonlinear effects and of controlling light-matter interactions with single site resolution.Ministerio de Ciencia, Innovación y Universidades (PGC2018-094792-B-100); Consejo Superior de Investigaciones CientÃficas (PTI-001);
Comunidad de Madrid (CAM 2020 Y2020/TCS-6545); Narodowe Centrum Nauki (DEC-2019/32/T/ST3/00332); Agence Nationale de la Recherche
(ANR-11-LABX-0007, ANR-16-CE30-0021, ANR-16-IDEX-0004 ULNE, ANR-QUAN-0003-05); European Research Council (820392, 865151, 949730),
Région Hauts-de-France
Topological gap solitons in a 1D non-Hermitian lattice
Nonlinear topological photonics is an emerging field aiming at extending the
fascinating properties of topological states to the realm where interactions
between the system constituents cannot be neglected. Interactions can indeed
trigger topological phase transitions, induce symmetry protection and
robustness properties for the many-body system. Moreover when coupling to the
environment via drive and dissipation is also considered, novel collective
phenomena are expected to emerge. Here, we report the nonlinear response of a
polariton lattice implementing a non-Hermitian version of the
Su-Schrieffer-Heeger model. We trigger the formation of solitons in the
topological gap of the band structure, and show that these solitons demonstrate
robust nonlinear properties with respect to defects, because of the underlying
sub-lattice symmetry. Leveraging on the system non-Hermiticity, we engineer the
drive phase pattern and unveil bulk solitons that have no counterpart in
conservative systems. They are localized on a single sub-lattice with a spatial
profile alike a topological edge state. Our results demonstrate a tool to
stabilize the nonlinear response of driven dissipative topological systems,
which may constitute a powerful resource for nonlinear topological photonics