79 research outputs found
Standardized Consent Forms for Surgical Procedures: An Intervention to Improve the Resident-led Informed Consent Process
Objectives and Goals:
To provide high quality, consistent consent forms for common surgical procedures and improve resident workflow by creating and implementing standardized printed consents for common surgical procedures.
These consents will be used by residents consenting patients in the ED or inpatient setting.
Consents shall include standardized procedure descriptions, risks and benefits of the procedure, and alternative treatment option descriptions, risks and benefitshttps://jdc.jefferson.edu/patientsafetyposters/1057/thumbnail.jp
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
Symmetry-breaking Effects for Polariton Condensates in Double-Well Potentials
We study the existence, stability, and dynamics of symmetric and anti-symmetric states of quasi-one-dimensional polariton condensates in double-well potentials, in the presence of nonresonant pumping and nonlinear damping. Some prototypical features of the system, such as the bifurcation of asymmetric solutions, are similar to the Hamiltonian analog of the double-well system considered in the realm of atomic condensates. Nevertheless, there are also some nontrivial differences including, e.g., the unstable nature of both the parent and the daughter branch emerging in the relevant pitchfork bifurcation for slightly larger values of atom numbers. Another interesting feature that does not appear in the atomic condensate case is that the bifurcation for attractive interactions is slightly sub-critical instead of supercritical. These conclusions of the bifurcation analysis are corroborated by direct numerical simulations examining the dynamics of the system in the unstable regime.MICINN (Spain) project FIS2008- 0484
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
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
Real-space collapse of a polariton condensate
Microcavity polaritons are two-dimensional bosonic fluids with strong nonlinearities,
composed of coupled photonic and electronic excitations. In their condensed form, they
display quantum hydrodynamic features similar to atomic Bose–Einstein condensates, such as
long-range coherence, superfluidity and quantized vorticity. Here we report the unique
phenomenology that is observed when a pulse of light impacts the polariton vacuum: the fluid
which is suddenly created does not splash but instead coheres into a very bright spot. The
real-space collapse into a sharp peak is at odd with the repulsive interactions of polaritons
and their positive mass, suggesting that an unconventional mechanism is at play. Our
modelling devises a possible explanation in the self-trapping due to a local heating of the
crystal lattice, that can be described as a collective polaron formed by a polariton condensate.
These observations hint at the polariton fluid dynamics in conditions of extreme intensities
and ultrafast times
Highly nonlinear trion-polaritons in a monolayer semiconductor
Highly nonlinear optical materials with strong effective photon-photon interactions are required for ultrafast and quantum optical signal processing circuitry. Here we report strong Kerr-like nonlinearities by employing efficient optical transitions of charged excitons (trions) observed in semiconducting transition metal dichalcogenides (TMDCs). By hybridising trions in monolayer MoSe2 at low electron densities with a microcavity mode, we realise trion-polaritons exhibiting significant energy shifts at small photon fluxes due to phase space filling. We find the ratio of trion- to neutral exciton–polariton interaction strength is in the range from 10 to 100 in TMDC materials and that trion-polariton nonlinearity is comparable to that in other polariton systems. The results are in good agreement with a theory accounting for the composite nature of excitons and trions and deviation of their statistics from that of ideal bosons and fermions. Our findings open a way to scalable quantum optics applications with TMDCs
Ultrafast-nonlinear ultraviolet pulse modulation in an AlInGaN polariton waveguide operating up to room temperature
Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. These rely on a strong intensity dependent (nonlinear) refractive index capable of modulating optical pulses on sub-picosecond timescales and on length scales suitable for integrated photonics. Currently there is no platform that can provide this for the UV spectral range where broadband spectra generated by nonlinear modulation can pave the way to new on-chip ultrafast (bio-) chemical spectroscopy devices. We introduce an AlInGaN waveguide supporting highly nonlinear UV hybrid light-matter states (exciton-polaritons) up to room temperature. We experimentally demonstrate ultrafast nonlinear spectral broadening of UV pulses in a compact 100 micrometer long device and measure a nonlinearity 1000 times that in common UV nonlinear materials and comparable to non-UV polariton devices. Our demonstration, utilising the mature AlInGaN platform, promises to underpin a new generation of integrated UV nonlinear light sources for advanced spectroscopy and measurement
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