Observation of the Transition from Lasing Driven by a Bosonic to a Fermionic Reservoir in a GaAs Quantum Well Microcavity

Brodbeck, Sebastian; Suchomel, Holger; Amthor, M.; Steinl, T.; Kamp, M.; Schneider, Christian; Höfling, Sven

doi:10.1103/physrevlett.117.127401

Cited by 6 publications

(9 citation statements)

References 27 publications

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“…Figure 2(a) shows the current as a function of the optical pump power, at constant voltage, for two different devices. Linear or sublinear dependence on the illumination power was observed in a very similar structure [20] when there was no extended polariton condensate in the ground state. We see sublinear behavior, as expected from the classical circuit model discussed in Appendix B, when we have a quasicondensate localized at the pump spot, e.g., as seen in the data of Device 1 at low power in Figure 2(a), where a clear saturation is seen.…”

Section: Resultsmentioning

confidence: 69%

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Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate

et al. 2018

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We show that when a monopolar current is passed through an n-i-n structure, superlinear photocurrent response occurs when there is a polariton condensate. This is in sharp contrast to the previously observed behavior for a standard semiconductor laser. Theoretical modeling shows that this is due to a stimulated exciton-exciton scattering process in which one exciton relaxes into the condensate, while another one dissociates into an electron-hole pair.Polariton condensation is now a well established effect [1][2][3]. The polaritons, which can be viewed as dressed photons with effective mass and repulsive interactions, undergo Bose-Einstein condensation and show many of the effects of bosonic stimulation and superfluidity [4,5], including rapidly flowing to the ground state of whatever potential profile they occupy [6]. Polariton condensates can range from strongly nonequilibrium all the way to equilibrium [7,8]. Many previous experiments have focused either on purely optical behavior, in which an optical pump produces optical emission from a polariton condensate; a small number have studied the production of a polariton condensate using electrical injection of free carriers in p-i-n structures [9][10][11]. In this paper, we show a unique effect of a polariton condensate acting the other way, in which the condensate strongly affects an electrical current. We show that the macroscopic coherence of the polariton wave function dramatically affects the electrical transport, even though the electrical current itself is incoherent. arXiv:1710.10920v3 [cond-mat.quant-gas] 18 Jun 2018 2 I. EXPERIMENTAL METHOD Figure 1(a) shows the structure of the samples used in our experiments. The central, activeregion consists of a pillar, typically 100 µm × 100 µm, which has two distributed-Bragg-reflector (DBR) mirrors, making up an optical cavity. Photons in the microcavity interact with excitons in the quantum wells placed at the antinodes of an optical mode. This part of the structure is the same as that used in previous experiments [6,7,[12][13][14] which showed long lifetime ( > ∼ 200 ps) and longdistance transport of polaritons (hundreds of microns to millimeters). Our pillar structure is similar to those studied by other groups [15,16], but the long lifetime of the polaritons in our structure allows the polaritons to move across the pillar and find the global potential-energy minima. As reported in Ref.[6] and shown here, in our structures the strain at the edges of the pillar leads to energy minima for the polaritons along the sides which trap the polariton condensate. Figure 1(c) shows a typical intrinsic energy profile for the polaritons, and Figure 1(d) shows the formation of the condensate in these edge traps when the laser light is focused tightly at the center of the pillar, about 40 µm from where the condensate forms at the edges. As discussed in Ref.[6], disconnected condensates initially form at the corners of the pillar and then lock to a monoenergetic condensate extending across the pillar as the polariton density ...

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Section: Resultsmentioning

confidence: 69%

“…[17][18][19], but in almost all cases with vertical injection; Ref. [20] also studied lateral injection, similar to our geometry, as discussed below.…”

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confidence: 86%

Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate

et al. 2018

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“…of polaritons may evolve into a standard semiconductor laser [19,20,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

“…However, the GB is absent in most of the PL experiments [1,6,30,[32][33][34][35][36][41][42][43][44][45]. There are only a few exceptions that reported observation of GB, which are the experiments done in extremely high density regime [40] or in a strongly disordered system [49] where polaritons were forced to scatter into the GB.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence and gain/absorption spectra of a driven-dissipative electron-hole-photon condensate

2018

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We investigate theoretically nonequilibrium effects on photoluminescence and gain/absorption spectra of a driven-dissipative exciton-polariton condensate, by employing the combined Hartree-Fock-Bogoliubov theory with the generalized random phase approximation extended to the Keldysh formalism. Our calculated photoluminescence spectra is in semiquantitative agreement with experiments, where features such as a blue shift of the emission from the condensate, the appearance of the dispersionless feature of a diffusive Goldstone mode, and the suppression of the dispersive profile of the mode are obtained. We show that the nonequilibrium nature of the exciton-polariton condensate strongly suppresses the visibility of the Bogoliubov dispersion in the negative energy branch (ghost branch) in photoluminescence spectra. We also show that the trace of this branch can be captured as a hole burning effect in gain/absorption spectra. Our results indicate that the nonequilibrium nature of the exciton-polariton condensate strongly reduces quantum depletion, while a scattering channel to the ghost branch is still present.PACS numbers: 03.75. Ss, ("X" in the right panel of Fig. 3(b)), where E bind X is the exciton binding energy. This allows us to define the detuning parameter between the cavity photon and the exciton state, (See the right panel of Fig. 3(b).) δ = ω cav − ω X .(3)

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“…Lagoudakis et al 9 showed exciton-polaritons can interact with carriers when free electrons and holes are introduced in the same in the same QW with the excitons or in a neighboring QW. Brodbeck et al 10 distinguished photon lasing from polariton lasing by monitoring the free carrier reservoir in a GaAs-based quantum well microcavity. It is expected to see some peculiar optical features when exciton-polaritons and free carriers are confined together.…”

Section: Introductionmentioning

confidence: 99%

Interaction between stimulated current injection and polariton condensate

Ozden¹,

Myers²,

Steger³

et al. 2018

Physics and Simulation of Optoelectronic Devices XXVI

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In this paper, we see a strong effect of the injected current on the light emission from the polariton condensate in an n-i-n structure, when we monitor the luminescence intensity under applied bias at various pump powers. We present here three thresholds for nonlinear increase of the intensity. We show that small changes of the incoherent injected current lead to stimulated enhancement of the coherent light emission from free carriers. We conclude that the polariton condensatecurrent system is a highly nonlinear electro-optical system.

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Observation of the Transition from Lasing Driven by a Bosonic to a Fermionic Reservoir in a GaAs Quantum Well Microcavity

Cited by 6 publications

References 27 publications

Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate

Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate

Photoluminescence and gain/absorption spectra of a driven-dissipative electron-hole-photon condensate

Interaction between stimulated current injection and polariton condensate

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