119 research outputs found
Filling the Void: A Low Cost, High-Yield Method to Addressing Incidental Findings in Trauma Patients
In this study we:
Report the incidence of incidental findings in a suburban trauma center treating primarily blunt and elderly trauma
Propose simple solutions to increase the rate of disclosure to patientshttps://jdc.jefferson.edu/patientsafetyposters/1070/thumbnail.jp
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Vortices in resonant polariton condensates in semiconductor microcavities
Covering general theoretical concepts and the research to date, this book demonstrates that Bose-Einstein condensation is a truly universal phenomenon
Polarization bistability and resultant spin rings in semiconductor microcavities
The transmission of a pump laser resonant with the lower polariton branch of
a semiconductor microcavity is shown to be highly dependent on the degree of
circular polarization of the pump. Spin dependent anisotropy of
polariton-polariton interactions allows the internal polarization to be
controlled by varying the pump power. The formation of spatial patterns, spin
rings with high degree of circular polarization, arising as a result of
polarization bistability, is observed. A phenomenological model based on spin
dependent Gross-Pitaevskii equations provides a good description of the
experimental results. Inclusion of interactions with the incoherent exciton
reservoir, which provides spin-independent blueshifts of the polariton modes,
is found to be essential.Comment: 5 pages, 3 figure
Logic Gates with Bright Dissipative Polariton Solitons in Bragg-Cavity Systems
Optical solitons are an ideal platform for the implementation of communication lines, since they can be packed extremely close one to another without risking partial loss of the encoded information due to their interaction. On the other hand, soliton-soliton interactions are needed to implement computations and achieve all-optical information processing. Here we study how bright dissipative polariton solitons interact and exploit their interaction to implement AND and OR gates with state of the art technology. Moreover, we show that soliton-soliton interaction can be used to determine the sign of {\alpha}2, the parameter describing the interaction between polaritons with opposite spin
Spatial patterns of dissipative polariton solitons in semiconductor microcavities
We report propagating bound microcavity polariton soliton arrays consisting of multipeak structures
either along (x) or perpendicular (y) to the direction of propagation. Soliton arrays of up to five solitons are
observed, with the number of solitons controlled by the size and power of the triggering laser pulse. The
breakup along the x direction occurs when the effective area of the trigger pulse exceeds the characteristic
soliton size determined by polariton-polariton interactions. Narrowing of soliton emission in energymomentum
space indicates phase locking between adjacent solitons, consistent with numerical modeling
which predicts stable multihump soliton solutions. In the y direction, the breakup originates from
inhomogeneity across the wave front in the transverse direction which develops into a stable array only in
the solitonic regime via phase-dependent interactions of propagating fronts
Lattices of quantized vortices in polariton superfluids
In this review, we will focus on the description of the recent studies conducted in the
quest for the observation of lattices of quantized vortices in resonantly injected polariton
superfluids. In particular, we will show how the implementation of optical traps for
polaritons allows for the realization of vortex–antivortex lattices in confined geometries
and how the development of a flexible method to inject a controlled orbital angular
momentum (OAM) in such systems results in the observation of patterns of same-sign
vortices
Effect of the GaAsP shell on optical properties of self-catalyzed GaAs nanowires grown on silicon
We realize growth of self-catalyzed core-shell GaAs/GaAsP nanowires (NWs) on
Si substrates using molecular-beam epitaxy. Transmission electron microscopy
(TEM) of single GaAs/GaAsP NWs confirms their high crystal quality and shows
domination of the zinc-blende phase. This is further confirmed in optics of
single NWs, studied using cw and time-resolved photoluminescence (PL). A
detailed comparison with uncapped GaAs NWs emphasizes the effect of the GaAsP
capping in suppressing the non-radiative surface states: significant PL
enhancement in the core-shell structures exceeding 2000 times at 10K is
observed; in uncapped NWs PL is quenched at 60K whereas single core-shell
GaAs/GaAsP NWs exhibit bright emission even at room temperature. From analysis
of the PL temperature dependence in both types of NW we are able to determine
the main carrier escape mechanisms leading to the PL quench
Observation of bright polariton solitons in a semiconductor microcavity
Microcavity polaritons are composite half-light half-matter quasi-particles,
which have recently been demonstrated to exhibit rich physical properties, such
as non-equilibrium Bose-Einstein condensation, parametric scattering and
superfluidity. At the same time, polaritons have some important advantages over
photons for information processing applications, since their excitonic
component leads to weaker diffraction and stronger inter-particle interactions,
implying, respectively, tighter localization and lower powers for nonlinear
functionality. Here we present the first experimental observations of bright
polariton solitons in a strongly coupled semiconductor microcavity. The
polariton solitons are shown to be non-diffracting high density wavepackets,
that are strongly localised in real space with a corresponding broad spectrum
in momentum space. Unlike solitons known in other matter-wave systems such as
Bose condensed ultracold atomic gases, they are non-equilibrium and rely on a
balance between losses and external pumping. Microcavity polariton solitons are
excited on picosecond timescales, and thus have significant benefits for
ultrafast switching and transfer of information over their light only
counterparts, semiconductor cavity lasers (VCSELs), which have only nanosecond
response time
Role of supercurrents on vortices formation in polariton condensates
Observation of quantized vortices in non-equilibrium polariton condensates
has been reported either by spontaneous formation and pinning in the presence
of disorder or by imprinting them onto the signal or idler of an optical
parametric oscillator (OPO). Here, we report a detailed analysis of the
creation and annihilation of polariton vortex-antivortex pairs in the signal
state of a polariton OPO by means of a short optical Gaussian pulse at a
certain finite pump wave-vector. A time-resolved, interferometric analysis of
the emission allows us to extract the phase of the perturbed condensate and to
reveal the dynamics of the supercurrents created by the pulsed probe. This flow
is responsible for the appearance of the topological defects when
counter-propagating to the underlying currents of the OPO signal.Comment: 8 pages, 5 figure
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