5,340 research outputs found
Slow-light enhancement of Beer-Lambert-Bouguer absorption
We theoretically show how slow light in an optofluidic environment
facilitates enhanced light-matter interactions, by orders of magnitude. The
proposed concept provides strong opportunities for improving existing
miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption
measurements widely employed in analytical chemistry.Comment: 4 pages including 4 figures. Accepted for AP
Mode-Field Radius of Photonic Crystal Fibers Expressed by the V-parameter
We numerically calculate the equivalent mode-field radius of the fundamental
mode in a photonic crystal fiber (PCF) and show that this is a function of the
V-parameter only and not the relative hole size. This dependency is similar to
what is found for graded-index standard fibers and we furthermore show that the
relation for the PCF can be excellently approximated with the same general
mathematical expression. This is to our knowledge the first semi-analytical
description of the mode-field radius of a PCF.Comment: Accepted for Opt. Let
Predicting macrobending loss for large-mode area photonic crystal fibers
We report on an easy-to-evaluate expression for the prediction of the
bend-loss for a large mode area photonic crystal fiber (PCF) with a triangular
air-hole lattice. The expression is based on a recently proposed formulation of
the V-parameter for a PCF and contains no free parameters. The validity of the
expression is verified experimentally for varying fiber parameters as well as
bend radius. The typical deviation between the position of the measured and the
predicted bend loss edge is within measurement uncertainty.Comment: Accepted for Optics Expres
Low-loss criterion and effective area considerations for photonic crystal fibers
We study the class of endlessly single-mode all-silica photonic crystal
fibers with a triangular air-hole cladding. We consider the sensibility to
longitudinal nonuniformities and the consequences and limitations for realizing
low-loss large-mode area photonic crystal fibers. We also discuss the
dominating scattering mechanism and experimentally we confirm that both macro
and micro-bending can be the limiting factor.Comment: Accepted for Journal of Optics A - Pure and Applied Optic
Plasmon-exciton polaritons in 2D semiconductor/metal interfaces
The realization and control of polaritons is of paramount importance in the
prospect of novel photonic devices. Here, we investigate the emergence of
plasmon-exciton polaritons in hybrid structures consisting of a two-dimensional
(2D) transition metal dichalcogenide (TMDC) deposited onto a metal substrate or
coating a metallic thin-film. We determine the polaritonic spectrum and show
that, in the former case, the addition of a top dielectric layer, and, in the
latter, the thickness of the metal film,can be used to tune and promote
plasmon-exciton interactions well within the strong coupling regime. Our
results demonstrate that Rabi splittings exceeding 100 meV can be readily
achieved in planar dielectric/TMDC/metal structures under ambient conditions.
We thus believe that this work provides a simple and intuitive picture to
tailor strong coupling in plexcitonics, with potential applications for
engineering compact photonic devices with tunable optical properties.Comment: 6 pages, including 5 figures and reference
Improved large-mode area endlessly single-mode photonic crystal fibers
We numerically study the possibilities for improved large-mode area endlessly
single mode photonic crystal fibers for use in high-power delivery
applications. By carefully choosing the optimal hole diameter we find that a
triangular core formed by three missing neighboring air holes considerably
improves the mode area and loss properties compared to the case with a core
formed by one missing air hole. In a realized fiber we demonstrate an
enhancement of the mode area by ~30 % without a corresponding increase in the
attenuation.Comment: 3 pages including 3 eps-figures. Accepted for Optics Letter
Modal cut-off and the V-parameter in photonic crystal fibers
We address the long-standing unresolved problem concerning the V-parameter in
a photonic crystal fiber (PCF). Formulate the parameter appropriate for a
core-defect in a periodic structure we argue that the multi-mode cut-off occurs
at a wavelength lambda* which satisfies V_PCF(lambda*)=pi. Comparing to
numerics and recent cut-off calculations we confirm this result.Comment: 3 pages including 2 figures. Accepted for Optics Letter
Low-loss photonic crystal fibers for transmission systems and their dispersion properties
We report on a single-mode photonic crystal fiber with attenuation and
effective area at 1550 nm of 0.48 dB/km and 130 square-micron, respectively.
This is, to our knowledge, the lowest loss reported for a PCF not made from VAD
prepared silica and at the same time the largest effective area for a low-loss
(< 1 dB/km) PCF. We briefly discuss the future applications of PCFs for data
transmission and show for the first time, both numerically and experimentally,
how the group velocity dispersion is related to the mode field diameterComment: 5 pages including 3 figures + 1 table. Accepted for Opt. Expres
Photonic crystal fiber with a hybrid honeycomb cladding
We consider an air-silica honeycomb lattice and demonstrate a new approach to
the formation of a core defect. Typically, a high or low-index core is formed
by adding a high-index region or an additional air-hole (or other low-index
material) to the lattice, but here we discuss how a core defect can be formed
by manipulating the cladding region rather than the core region itself.
Germanium-doping of the honeycomb lattice has recently been suggested for the
formation of a photonic band-gap guiding silica-core and here we experimentally
demonstrate how an index-guiding silica-core can be formed by fluorine-doping
of the honeycomb lattice.Comment: 5 pages including 3 figures. Accepted for Optics Expres
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