2,525 research outputs found
Quantum Exciton-Polariton Networks through Inverse Four-Wave Mixing
We demonstrate the potential of quantum operation using lattices of
exciton-polaritons in patterned semiconductor microcavities. By introducing an
inverse four-wave mixing scheme acting on localized modes, we show that it is
possible to develop non-classical correlations between individual condensates.
This allows a concept of quantum exciton-polariton networks, characterized by
the appearance of multimode entanglement even in the presence of realistic
levels of dissipation.Comment: 5 pages, 4 figures, pre-review version of manuscrip
Spontaneous and Superfluid Chiral Edge States in Exciton-Polariton Condensates
We present a scheme of interaction-induced topological bandstructures based
on the spin anisotropy of exciton-polaritons in semiconductor microcavities. We
predict theoretically that this scheme allows the engineering of topological
gaps, without requiring a magnetic field or strong spin-orbit interaction
(transverse electric-transverse magnetic splitting). Under non-resonant
pumping, we find that an initially topologically trivial system undergoes a
topological transition upon the spontaneous breaking of phase symmetry
associated with polariton condensation. Under resonant coherent pumping, we
find that it is also possible to engineer a topological dispersion that is
linear in wavevector -- a property associated with polariton superfluidity.Comment: 6 pages, 4 figure
Exciton-Polariton Oscillations in Real Space
We introduce and model spin-Rabi oscillations based on exciton-polaritons in
semiconductor microcavities. The phase and polarization of oscillations can be
controlled by resonant coherent pulses and the propagation of oscillating
domains gives rise to phase-dependent interference patterns in real space. We
show that interbranch polariton-polariton scattering controls the propagation
of oscillating domains, which can be used to realize logic gates based on an
analogue variable phase.Comment: 6 page
Stochastic Gross-Pitaevskii Equation for the Dynamical Thermalization of Bose-Einstein Condensates
We present a theory for the description of energy relaxation in a
nonequilibrium condensate of bosonic particles. The approach is based on
coupling to a thermal bath of other particles (e.g., phonons in a crystal, or
noncondensed atoms in a cold atom system), which are treated with a Monte Carlo
type approach. Together with a full account of particle-particle interactions,
dynamic driving, and particle loss, this offers a complete description of
recent experiments in which Bose-Einstein condensates are seen to relax their
energy as they propagate in real space and time. As an example, we apply the
theory to the solid-state system of microcavity exciton polaritons, in which
nonequilibrium effects are particularly prominent.Comment: Manuscript: 5 pages (Main Text) + 2 figures + 4 pages (Supplemental
Material). Proofs versio
Multivalley engineering in semiconductor microcavities
We consider exciton-photon coupling in semiconductor microcavities in which
separate periodic potentials have been embedded for excitons and photons. We
show theoretically that this system supports degenerate ground-states appearing
at non-zero in-plane momenta, corresponding to multiple valleys in reciprocal
space, which are further separated in polarization corresponding to a
polarization-valley coupling in the system. Aside forming a basis for
valleytronics, the multivalley dispersion is predicted to allow for spontaneous
momentum symmetry breaking and two-mode squeezing under non-resonant and
resonant excitation, respectively.Comment: Manuscript: 7 pages, 7 figures, published in Scientific Reports 7,
45243 (2017
Incoherent excitation and switching of spin states in exciton-polariton condensates
We investigate, theoretically and numerically, the spin dynamics of a
two-component exciton-polariton condensate created and sustained by
non-resonant spin-polarized optical pumping of a semiconductor microcavity.
Using the open-dissipative mean-field model, we show that the existence of well
defined phase-locked steady states of the condensate may lead to efficient
switching and control of spin (polarization) states with a non-resonant
excitation. Spatially inhomogeneous pulsed excitations can cause symmetry
breaking in the pseudo-spin structure of the condensate and lead to formation
of non-trivial spin textures. Our model is universally applicable to two weakly
coupled polariton condensates, and therefore can also describe the behaviour of
condensate populations and phases in 'double-well' type potentials
The Design for a Nanoscale Single-Photon Spin Splitter
We propose using the effective spin-orbit interaction of light in
Bragg-modulated cylindrical waveguides for the effcient separation of spin-up
and spin-down photons emitted by a single photon emitter. Due to the spin and
directional dependence of photonic stopbands in the waveguides, spin-up (down)
photon propagation in the negative (positive) direction along the waveguide
axis is blocked while the same photon freely propagates in the opposite
direction.Comment: 5 pages, 3 figure
Spontaneous Pattern Formation in a Polariton Condensate
Polariton condensation can be regarded as a self-organization phenomenon,
where phase ordering is established among particles in the system. In such
condensed systems, further ordering can possibly occur in the particle density
distribution, under particular experimental conditions. In this work we report
on spontaneous pattern formation in a polariton condensate under non-resonant
optical pumping. The slightly elliptical ring-shaped excitation laser we employ
is such to force condensation to occur in a single-energy state with periodic
boundary conditions, giving rise to a multi-lobe standing wave patterned state
Monolithic Arrays of Grating-Surface-Emitting Diode Lasers and Quantum Well Modulators for Optical Communications
The electro-optic switching properties of injection-coupled coherent 2-D grating-surface-emitting laser arrays with multiple gain sections and quantum well active layers are discussed and demonstrated. Within such an array of injection-coupled grating-surface-emitting lasers, a single gain section can be operated as intra-cavity saturable loss element that can modulate the output of the entire array. Experimental results demonstrate efficient sub-nanosecond switching of high power grading-surface-emitting laser arrays by using only one gain section as an intra-cavity loss modulator
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