5,494 research outputs found
Optically induced transparency in bosonic cascade lasers
Bosonic cascade lasers are terahertz (THz) lasers based on stimulated
radiative transitions between bosonic condensates of excitons or
exciton-polaritons confined in a trap. We study the interaction of an incoming
THz pulse resonant in frequency with the transitions between neighboring energy
levels of the cascade. We show that at certain optical pump conditions the
cascade becomes transparent to the incident pulse: it neither absorbs nor
amplifies it, in the mean field approximation. The populations of intermediate
levels of the bosonic cascade change as the THz pulse passes, nevertheless. In
comparison, a fermionic cascade laser does not reveal any of these properties.Comment: 4 pages, 5 figure
Magnetic Field Control of the Optical Spin Hall Effect
We investigate theoretically the effect of an external magnetic field on
polarization patterns appearing in quantum microcavities due to the optical
spin Hall effect (OSHE). We show that increase of the magnetic field
perpendicular to the plane of the cavity resulting in the increase of the
Zeeman splitting leads to the transition from azimuthal separation of
polarizations to their radial separation. This effect can be straightforwardly
detected experimentally.Comment: 9 pages, 6 figure
Switching waves in multi-level incoherently driven polariton condensates
We show theoretically that an open-dissipative polariton condensate confined
within a trapping potential and driven by an incoherent pumping scheme gives
rise to bistability between odd and even modes of the potential. Switching from
one state to the other can be controlled via incoherent pulsing which becomes
an important step towards construction of low-powered opto-electronic devices.
The origin of the effect comes from modulational instability between odd and
even states of the trapping potential governed by the nonlinear
polariton-polariton interactions
Parity solitons in nonresonantly driven-dissipative condensate channels
We study analytically and numerically the condensation of a
driven-dissipative exciton-polariton system using symmetric nonresonant pumping
geometries. We show that the lowest condensation threshold solution carries a
definite parity as a consequence of the symmetric excitation profile. At higher
pump intensities competition between the two parities can result in critical
quenching of one and saturation of the other. Using long pump channels, we show
that the competition of the condensate parities gives rise to a different type
of topologically stable defect propagating indefinitely along the condensate.
The defects display repulsive interactions and are characterized by a sustained
wavepacket carrying a pair of opposite parity domain walls in the condensate
channel
Optomechanics with Cavity Polaritons: Dissipative Coupling and Unconventional Bistability
We study a hybrid system formed from an optomechanical resonator and a cavity
mode strongly coupled to an excitonic transition inside a quantum well. We show
that due to the mixing of cavity photon and exciton states, the emergent
quasiparticles - polaritons - possess coupling to the mechanical mode of both
dispersive and dissipative nature. We calculate the occupancies of polariton
modes and reveal bistable behavior, which deviates from conventional Kerr
nonlinearity or dispersive coupling cases due to the dissipative coupling. The
described system serves as a good candidate for future polaritonic devices and
solid state quantum information processing.Comment: 5 pages, 4 figure
Tunable single photon emission from dipolaritons
We study a system comprising of a double quantum well embedded in a
micropillar optical cavity, where strong coupling between a direct exciton,
indirect exciton, and cavity photon is achieved. We show that the resulting
hybrid quasiparticles - dipolaritons - can induce strong photon correlations
and lead to anti-bunched behaviour of the cavity output field. The origin of
the observed single photon emission is attributed to unconventional photon
blockade. Moreover, we find that the second-order equal time correlation
function can be tuned over a large range using an electric field
applied to the structure, or changing the frequency of the pump. This allows
for an on-the-flight control of cavity output properties, and is important for
the future generation of tunable single photon emission sources.Comment: 10 pages, 5 figure
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
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
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