Enhanced coherence between condensates formed resonantly at different times

Hayat, Alex; Lange, Christoph; Rozema, Lee A.; Chang, Rockson; Potnis, Shreyas; Driel, H. M. van; Steinberg, Aephraim M.; Steger, Mark; Snoke, D. W.; Pfeiffer, L. N.; West, K. W.

doi:10.1364/oe.22.030559

Cited by 2 publications

(2 citation statements)

References 34 publications

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“…Their bosonic nature, together with their low effective mass and reduced density of states, facilitates their condensation in a macroscopic coherent phase that presents high similarities to Bose-Einstein condensates (BECs) [4]. Coherence is a key ingredient of condensates, and has been intensely studied both in atomic BECs [5], and in polariton condensates [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The coherence has been mostly investigated in realspace, by studying interference effects, either for static condensates [11,24,25] or for moving ones when they meet in real-space [10,26].…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of the coherence in polariton condensates

et al. 2018

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We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real-and reciprocal-space allows us to fully monitor the condensates' dynamics. We obtain fringes in reciprocal-space as a result of the interference between polariton wavepackets (WPs) traveling with the same speed. The periodicity of these fringes is inversely proportional to the spatial distance between the interfering WPs. In a similar fashion, we obtain interference fringes in real-space when WPs traveling in opposite directions meet. The visibility of both real-and reciprocal-space interference fringes rapidly decreases with increasing temperature and vanishes. A theoretical description of the phase transition, considering the coexistence of condensed and non-condensed particles, for an out-of-equilibrium condensate such as ours is still missing. Yet a comparison with theories developed for atomic condensates allows us to infer a critical temperature for the BEC-like transition when the visibility goes to zero.

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Section: Introductionmentioning

confidence: 99%

Temperature dependence of the coherence in polariton condensates

et al. 2018

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“…Moreover, the very short lifetime of cavity-polaritons can in principle guarantee extremely fast operation rates. For these reasons, in recent years significant efforts have been devoted to the dynamical control of polaritonic systems and several proposals have been made to implement switches, spin-switches, transistors, and resonant tunneling diodes on cavity-polariton systems [1][2][3][4][5][6][7][8][9].…”

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confidence: 99%

Ultrafast Stark-Induced Polaritonic Switches

et al. 2014

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A laser pulse, several meV red-detuned from the excitonic line of a quantum well, has been shown to induce an almost instantaneous and rigid shift of the lower and upper polariton branches. Here we demonstrate that through this shift, ultra-fast all-optical control of the polariton population in a semiconductor microcavity should be achievable. In the proposed setup a Stark field is used to bring the lower polariton branch in or out of resonance with a quasi-resonant continuous-wave laser, thereby favoring or inhibiting the injection of polaritons into the cavity. Moreover we show that this technique allows for the implementation of optical switches with extremely high repetition rates.PACS numbers: 42.50. Pq, 42.79.Ta, 71.36.+c Systems made of quantum wells embedded in semiconductor microcavities, where light and matter are strongly coupled, provide a versatile area for the study of fundamental physics and new states of matter such as outof-equilibrium polariton condensates. Due to the strong non-linear interaction between polaritons, they also have great potential for the implementation of next-generation all-optical computational technologies. Moreover, the very short lifetime of cavity-polaritons can in principle guarantee extremely fast operation rates. For these reasons, in recent years significant efforts have been devoted to the dynamical control of polaritonic systems and several proposals have been made to implement switches, spin-switches, transistors, and resonant tunneling diodes on cavity-polariton systems [1-9].The general idea underlying all these proposals is to use exciton-exciton/polariton-polariton interactions to control the blueshift of the lower-polariton branch directly with the driving laser and, in this way, to manipulate the number of polaritons in a given spatial location and given energy state of a microcavity. The main disadvantage of this technique is that when the duration of the laser pulses used to trigger the desired operations is in the sub-picosecond regime, the corresponding bandwidth is of the order of the Rabi splitting of the system. Therefore, the effect of short pulses is not only to inject polaritons, but also to excite exciton reservoirs with relatively long lifetimes that relax into polaritons and considerably slow down the dynamics of the system. As a result, the dynamical control of polariton systems has not yet reached the ps or sub-ps regime.Instead, the idea underlying the present work is to shift the energy of the polariton branches using the Stark effect produced by a laser far red-detuned from the excitonic line. It has been recently shown [10] that the dynamic Stark effect can be used to shift both the lower polariton (LP) and the upper polariton (UP) branches almost rigidly, with the shift lasting only for the duration of the Stark pulse (typically less than a ps). This ultra-fast control is possible because the Stark pulse does not excite reservoirs of long-lived particles.In this letter, we propose a setup where a continuouswave laser (CW) is used to r...

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Enhanced coherence between condensates formed resonantly at different times

Cited by 2 publications

References 34 publications

Temperature dependence of the coherence in polariton condensates

Temperature dependence of the coherence in polariton condensates

Ultrafast Stark-Induced Polaritonic Switches

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