Tracking Dark Excitons with Exciton Polaritons in Semiconductor Microcavities

Schmidt, Daniel; Berger, Bernd; Kahlert, Marius; Bayer, М.; Schneider, Christian; Höfling, Sven; Sedov, Evgeny; Kavokin, A. V.; Aßmann, Marc

doi:10.1103/physrevlett.122.047403

Cited by 22 publications

(11 citation statements)

References 43 publications

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“…Thus, polariton condensation is necessarily accompanied by the formation of an incoherent uncondensed excitonic reservoir [8]. Such a reservoir can also manifest itself indirectly in experiments via its repulsive interactions with polaritons [19][20][21][22], allowing the creation of on-demand trapping potentials by spatially selective laser excitation [23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Bogoliubov excitations of a polariton condensate in dynamical equilibrium with an incoherent reservoir

Pieczarka,

Bleu,

Estrecho

et al. 2021

Preprint

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The classic Bogoliubov theory of weakly interacting Bose gases rests upon the assumption that nearly all the bosons condense into the lowest quantum state at sufficiently low temperatures. Here we develop a generalized version of Bogoliubov theory for the case of a driven-dissipative excitonpolariton condensate with a large incoherent uncondensed component, or excitonic reservoir. We argue that such a reservoir can consist of both excitonic high-momentum polaritons and optically dark superpositions of excitons across different optically active layers, such as multiple quantum wells in a microcavity. In particular, we predict interconversion between the dark and bright (lightcoupled) excitonic states that can lead to a dynamical equilibrium between the condensate and reservoir populations. We show that the presence of the reservoir fundamentally modifies both the energy and the amplitudes of the Bogoliubov quasiparticle excitations due to the non-Galileaninvariant nature of polaritons. Our theoretical findings are supported by our experiment, where we directly detect the Bogoliubov excitation branches of an optically trapped polariton condensate in the high-density regime. By analyzing the measured occupations of the excitation branches, we extract the Bogoliubov amplitudes across a range of momenta and show that they agree with our generalized theory.

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Section: Introductionmentioning

confidence: 99%

Bogoliubov excitations of a polariton condensate in dynamical equilibrium with an incoherent reservoir

Pieczarka,

Bleu,

Estrecho

et al. 2021

Preprint

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“…In the microcavity structures, the reservoir determines many important properties of the polariton radiation such as the threshold of the polariton laser, multistability, etc., see e.g., Refs. [7][8][9][10][11][12] .…”

Section: Introductionmentioning

confidence: 99%

“…Recently a new approach of tracking dark excitons in the reservoir with exciton polaritons was suggested 11 . This method is based on polariton bistability revealed the long-lived (> 20 ns) exciton reservoir in microcavity exciton-polariton systems.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and control of nonradiative excitons - free carriers mixture in GaAs/AlGaAs quantum wells

Kurdyubov,

Trifonov,

Gribakin

et al. 2021

Preprint

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Dynamics of nonradiative excitons with large in-plane wave vectors forming a so-called reservoir is experimentally studied in a high-quality semiconductor structure containing a 14-nm shallow GaAs/Al0.03Ga0.97As quantum well by means of the non-degenerate pump-probe spectroscopy. The exciton dynamics is visualized via the dynamic broadening of the heavy-hole and light-hole exciton resonances caused by the exciton-exciton scattering. Under the non-resonant excitation free carriers are optically generated. In this regime the exciton dynamics is strongly affected by the excitoncarrier scattering. In particular, if the carriers of one sign are prevailing, they efficiently deplete the reservoir of the nonradiative excitons inducing their scattering into the light cone. A simple model of the exciton dynamics is developed, which considers the energy relaxation of photocreated electrons and holes, their coupling into excitons, and exciton scattering into the light cone. The model well reproduces the exciton dynamics observed experimentally both at the resonant and nonresonant excitation. Moreover, it correctly describes the profiles of the photoluminescence pulses studied experimentally. The efficient exciton-electron interaction is further experimentally verified by the control of the exciton density in the reservoir when an additional excitation creates electrons depleting the reservoir.

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“…Dark, or spin-forbidden (J = ±2), excitons are injected in the system at nonresonant excita-tion together with bright (J = ±1) exciton populations (overall, there are four exciton branches per each quantum well filled from the relaxing charge carriers). Current studies show that such dark reservoir can be highly populated [31] and long-lived [32]. Its influence on polariton properties however is mostly unexplored.…”

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confidence: 99%