Negatively Charged Quantum Well Polaritons in a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>GaAs</mml:mi><mml:mi>/</mml:mi><mml:mi>AlAs</mml:mi></mml:math>Microcavity: An Analog of Atoms in a Cavity

Rapaport, Ronen; Harel, R.; Cohen, E.; Ron, A.; Linder, E.; Pfeiffer, L. N.

doi:10.1103/physrevlett.84.1607

Cited by 50 publications

(55 citation statements)

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“…An additional effect that can modify the cavity dispersion in this regime is the appearance of a trion state coupled to the cavity modes. 22 In this case the stimulated scattering of polaritons can be accompanied by dissociation of trions while the effect remains qualitatively similar. Further we shall neglect the trions for simplicity.…”

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confidence: 83%

“…The advantage of this scattering mechanism with respect to previously discussed ones is that ͑i͒ the matrix element of electron-exciton scattering is quite large, 21,22 ͑ii͒ the electron has a much lighter mass than an exciton, thus the energy relaxation of a polariton from the bottleneck region to the ground state requires fewer scattering events than for polariton-polariton or polariton-phonon scattering. These advantages are found to be strong enough to restore fast polariton relaxation and allow the polaritons to condense into their traped state.…”

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confidence: 99%

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Polariton lasing by exciton-electron scattering in semiconductor microcavities

et al. 2002

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The relaxation bottleneck present in the dispersion relation of exciton polaritons in semiconductor microcavities has prevented the realization of low threshold lasing based on exciton-polariton condensation. Here we show theoretically that the introduction of a cold electron gas into such structures induces efficient electronpolariton scattering. This process allows the condensation of the polaritons accumulated at the bottleneck to the final emitting state with a transition time of a few picoseconds, opening the way to a new generation of low-threshold light-emitting devices. DOI: 10.1103/PhysRevB.65.153310 PACS number͑s͒: 78.47.ϩp, 42.50.Ϫp, 42.65.Ϫk, 71.36.ϩc The observation of the strong coupling of light with excitons in semiconductor microcavities 1 has generated much speculation regarding the possibility for low-threshold optical devices.2,3 Realization of such devices based on the Bosonic character of the optical eigenmodes ͑exciton polaritons 4 ͒ of these structures would be a revolutionary step in semiconductor optics. However, Bose condensation of exciton polaritons has not yet been observed. One of the main obstacles is set by a bottleneck in the polariton relaxation rate.5-7 As a result, the emission of the microcavity under nonresonant excitation remains weak and nondirectional.Here we propose an original relaxation mechanism based on the scattering of polaritons with free electrons. This allows polaritons to relax efficiently from the bottleneck region to the lowest energy state once free electrons are introduced into the active region either via doping or by photoexcitation. This opens the way to realization of lowthreshold laserlike devices based on cavity polaritons.The basic principle of a polariton laser is illustrated in Fig. 1͑a͒ using the dispersion curve of the lower branch exciton polaritons in a typical microcavity. The strong-coupling regime creates a trap containing a small number of polariton states at energies below all other states in the semiconductor. This polariton trap is sharp with a depth equal to nearly half the splitting ⍀ between the two polariton modes. Polaritons in the trap are half photon and half exciton, and have properties suitable for the Bose condensation of exciton polaritons once sufficiently populated. Recombination from this state in the Bose condensation regime is coherent, monochromatic, and sharply directed, characteristic of laser emission. The relaxation of polaritons into the kϭ0 state is found to be stimulated if the population of the final state is larger than 1. The amplification process proposed here is physically very different from the classical lasing process.9 In particular, the threshold to lasing which in conventional lasers is conditional on the inversion of population is only dependent on the lifetime of the ground state in the polariton laser. As soon as relaxation to the ground state of the trap becomes faster than the radiative recombination from this state, optical amplification is achieved. Note that the absorption and re-absorption...

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Polariton lasing by exciton-electron scattering in semiconductor microcavities

et al. 2002

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“…Recently, there has been a lot of interest in polaritons formed from photons confined in cavities: such cavity polaritons have now been observed for confined photons coupled to atoms, 3 to two-dimensional excitons in quantum wells, 4 to bulk excitons, 5 to excitons in films of organic semiconductors, 6,7 and to charged exciton complexes. 8 Since polaritons are photons coupled to other excitations, they are bosons, and so are candidates for Bose condensation. 9 Recent observations [10][11][12][13][14] of bosonic behavior for cavity polaritons have renewed interest in this idea.…”

Section: Introductionmentioning

confidence: 99%

Bose condensation of cavity polaritons beyond the linear regime: The thermal equilibrium of a model microcavity

Eastham¹,

Littlewood²

2001

Phys. Rev. B

154

199

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We consider a generalization of the Dicke model. This model describes localized, physically separated, saturable excitations, such as excitons bound on impurities, coupled to a single long-lived mode of an optical cavity. We consider the thermal equilibrium of this model at a fixed total number of excitons and photons. We find a phase in which both the cavity field and the excitonic polarization are coherent. This phase corresponds to a Bose condensate of cavity polaritons, generalized to allow for the fermionic internal structure of the excitons. It is separated from the normal state by an unusual reentrant phase boundary. We calculate the excitation energies of the model, and hence the optical absorption spectra of the cavity. In the condensed phase the absorption spectrum is gapped. The presence of this gap distinguishes the polariton condensate from the normal state and from a conventional laser, even when the inhomogeneous linewidth of the excitons is so large that there is no observable polariton splitting in the normal state.

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“…In the first case, it was demonstrated with coupled planar microcavities [13][14][15][16] or by confining the optical mode in more than one dimension [5,17]. The coupling of a single cavity mode to many exciton states has been achieved through the monolayer thickness variation of GaAs/AlAs QWs [18], with QWs of different thicknesses [19] or when coupling to the charged exciton transition [20,21].…”

Section: Introductionmentioning

confidence: 99%

Multiple polariton modes originating from the coupling of quantum wells in planar microcavity

et al. 2015

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We report on the observation of multiple polariton modes, originating from an electronic coupling between quantum wells inside a planar microcavity. A series of excitonic transitions are measured for a bare quantum well stack and are precisely identified to electron-hole transitions originating from the coupling of the wells. When the quantum well stacks are placed at the antinode of a high Q-factor microcavity, a series of anticrossings is observed, which is characteristic of a multiplicity of polariton modes. This behavior is simulated using a coupled oscillator model accounting for the cavity mode and all allowed excitonic transitions.

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Negatively Charged Quantum Well Polaritons in aGaAs/AlAsMicrocavity: An Analog of Atoms in a Cavity

Abstract: The negatively charged exciton (X-) is observed to strongly couple with the microcavity- (MC-)confined photons in a GaAs quantum well containing a two-dimensional electron gas with 0 Show more

Cited by 50 publications

References 15 publications

Polariton lasing by exciton-electron scattering in semiconductor microcavities

Polariton lasing by exciton-electron scattering in semiconductor microcavities

Bose condensation of cavity polaritons beyond the linear regime: The thermal equilibrium of a model microcavity

Multiple polariton modes originating from the coupling of quantum wells in planar microcavity

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