36,910 research outputs found
Strongly coupled slow-light polaritons in one-dimensional disordered localized states
Cavity quantum electrodynamics advances the coherent control of a single
quantum emitter with a quantized radiation field mode, typically piecewise
engineered for the highest finesse and confinement in the cavity field. This
enables the possibility of strong coupling for chip-scale quantum processing,
but till now is limited to few research groups that can achieve the precision
and deterministic requirements for these polariton states. Here we observe for
the first time coherent polariton states of strong coupled single quantum dot
excitons in inherently disordered one-dimensional localized modes in slow-light
photonic crystals. Large vacuum Rabi splittings up to 311 {\mu}eV are observed,
one of the largest avoided crossings in the solid-state. Our tight-binding
models with quantum impurities detail these strong localized polaritons,
spanning different disorder strengths, complementary to model-extracted pure
dephasing and incoherent pumping rates. Such disorder-induced slow-light
polaritons provide a platform towards coherent control, collective
interactions, and quantum information processing.Comment: 17 pages, 5 figures and supplementary informatio
Optical meta-atom for localization of light with quantized energy
The capacity to confine light into a small region of space is of paramount
importance in many areas of modern science. Here, we suggest a mechanism to
store a quantized "bit" of light - with a very precise amount of energy - in an
open core-shell plasmonic structure ("meta-atom") with a nonlinear optical
response. Notwithstanding the trapped light state is embedded in the radiation
continuum, its lifetime is not limited by the radiation loss. Interestingly, it
is shown that the interplay between the nonlinear response and volume plasmons
enables breaking fundamental reciprocity restrictions, and coupling very
efficiently an external light source to the meta-atom. The collision of an
incident optical pulse with the meta-atom may be used to release the trapped
radiation "bit".Comment: Article in press in Nature Communications (29/09/2015). Attached:
Supplementary Movies 1 and 2 (small size version
A survey of localization in wireless sensor network
Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network
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