Influence of interactions with noncondensed particles on the coherence of a one-dimensional polariton condensate

Schmutzler, Johannes; Kazimierczuk, T.; Bayraktar, Ömer; Aßmann, Marc; Bayer, М.; Brodbeck, Sebastian; Kamp, M.; Schneider, Christian; Höfling, Sven

doi:10.1103/physrevb.89.115119

Cited by 24 publications

(21 citation statements)

References 32 publications

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“…It is significantly smaller than that of a quasiequilibrium condensate formed under a nonresonant excitation [39]. That is well expected as the decoherence in a resonantly pumped system is mainly due to the scattering on phonons, whereas nonresonantly pumped condensates lose their coherence through the interaction with an exciton reservoir that is inevitably excited in the latter case [40,41].…”

Section: Methodsmentioning

confidence: 81%

Nonlinear route to intrinsic Josephson oscillations in spinor cavity-polariton condensates

et al. 2014

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The intrinsic Josephson effect is observed in a two-component polariton condensate in a strained planar microcavity under a resonant pulsed excitation such that only one of the two linearly polarized eigenstates is pumped from the outside. On reaching the threshold density, the polariton-polariton interaction involves a spontaneous breaking of the symmetry between spin-up and spin-down polaritons. As a result, the condensate acquires nearly circular polarization while the pump is strong and then passes to the Josephson oscillation regime since the pump weakens.

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Section: Methodsmentioning

confidence: 81%

Nonlinear route to intrinsic Josephson oscillations in spinor cavity-polariton condensates

et al. 2014

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“…The relaxation of the created hot excitons involves multiple-scattering processes, which destroy the coherence and phase of the excitation; this ensures that these properties are not inherited by the condensate, in contrast to the resonant excitation case. At the same time, the incoherent reservoir causes additional decoherence [14], forming a repulsive potential [15] which shapes the condensate spatially and spectrally. Moreover, it significantly affects the excitation spectrum of the condensate [16].…”

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confidence: 99%

Ghost Branch Photoluminescence From a Polariton Fluid Under Nonresonant Excitation

et al. 2015

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An expanding polariton condensate is investigated under pulsed nonresonant excitation with a small laser pump spot. Far above the condensation threshold we observe a pronounced increase in the dispersion curvature, with a subsequent linearization of the spectrum and strong luminescence from a ghost branch orthogonally polarized with respect to the linearly polarized condensate emission. Polarization of both branches is understood in terms of spin-dependent polariton-polariton scattering. The presence of the ghost branch has been confirmed in time-resolved measurements. The effects of disorder and dissipation in the photoluminescence of polariton condensates and their excitations are discussed. DOI: 10.1103/PhysRevLett.115.186401 PACS numbers: 71.36.+c, 67.10.-j, 71.35.Lk, 78.67.De Exciton polaritons are composite bosons consisting of strongly coupled microcavity photons and quantumwell excitons. They are able to form a novel class of condensates (for recent reviews see, e.g., [1,2]). Despite their nonequilibrium and dissipative nature, they behave as condensates of weakly interacting bosons. Collective phenomena like condensation [3], off-diagonal long-range order [4,5], topological excitations [6], or superfluid features in the propagation of polariton flows [7] have been demonstrated in such systems. A spectacular consequence of the parametric scattering in polariton gases is the appearance of nonparabolic scattering bands, including normal branches (NBs) and ghost branches (GBs), where the latter are populated by the virtual off-branch excitonpolaritons [7,8]. Excitations of polariton condensates are expected to be characterized by linearized dispersions of the Bogoliubov-like spectra [9]. The fluid excitations at low momenta are expected to behave as collective sound waves rather than as single particles. Recently, the linear dispersion NB and the GB of a resonantly pumped polariton condensate [10] have been observed in a four-wave mixing experiment.The experiment providing direct access to the dispersion of excitations of spontaneously formed condensates in polariton systems is photoluminescence (PL) under nonresonant excitation. The nonresonant pumping can be realized with either a detuned laser or the current injection [11,12]. In the nonresonant pumping scheme, incoherent excitons are generated and then relax, subsequently feeding the reservoir and governing the dynamics of the system [13]. The relaxation of the created hot excitons involves multiple-scattering processes, which destroy the coherence and phase of the excitation; this ensures that these properties are not inherited by the condensate, in contrast to the resonant excitation case. At the same time, the incoherent reservoir causes additional decoherence [14], forming a repulsive potential [15] which shapes the condensate spatially and spectrally. Moreover, it significantly affects the excitation spectrum of the condensate [16]. Bogoliubov dispersions have been reported in this excitation scheme; however, no fingerprints of the GB have been...

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“…6(c) In both scenarios the optically created potential interacts twofold with the incoming condensate: First the incoming flow is redirected due to repulsive Coulomb interaction with the background carriers, and second the potential barrier operates also as a gain medium, which gives rise to strong condensate emission in up to 15 μm distance from the source of the directed condensate flow. Nevertheless, the barrier remains separated in space from the condensate flow, which might be beneficial concerning the loss of coherence of a condensate mediated by the local presence of background carriers [40].…”

Section: Resultsmentioning

confidence: 99%

All-optical flow control of a polariton condensate using nonresonant excitation

et al. 2015

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The precise adjustment of the polariton condensate flow under incoherent excitation conditions is an indispensable prerequisite for polariton-based logic gate operations. In this report, an all-optical approach for steering the motion of a polariton condensate using only nonresonant excitation is demonstrated. We create arbitrarily shaped functional potentials by means of a spatial light modulator, which allow for tailoring the condensate state and guiding a propagating condensate along reconfigurable pathways. Additional numerical simulations confirm the experimental observations and elucidate the interaction effects between background carriers and polariton condensates.

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Influence of interactions with noncondensed particles on the coherence of a one-dimensional polariton condensate

Cited by 24 publications

References 32 publications

Nonlinear route to intrinsic Josephson oscillations in spinor cavity-polariton condensates

Nonlinear route to intrinsic Josephson oscillations in spinor cavity-polariton condensates

Ghost Branch Photoluminescence From a Polariton Fluid Under Nonresonant Excitation

All-optical flow control of a polariton condensate using nonresonant excitation

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