Macroscopic quantum self-trapping and Josephson oscillations of exciton polaritons
Macroscopic quantum self-trapping and Josephson oscillations of exciton polaritons
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DOI：
10.1038/nphys2609
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发表时间：
2013-05-01
期刊：
影响因子：
19.6
通讯作者：
Bloch, J.
中科院分区：
文献类型：
--
作者：
Abbarchi, M.;Amo, A.;Bloch, J.
两个宏观量子态通过隧道势垒的耦合引起约瑟夫森现象（1），如拉比振荡（2），交流。和直流效应（3），或宏观自陷，取决于隧穿还是相互作用占主导地位（4）。非线性约瑟夫森物理首先在超流氦（5）和原子凝聚体（6，7）中观察到，但在光子系统中仍然无法实现，因为它需要大的光子-光子相互作用。在这里，我们报告了两个耦合的极化激元凝聚体的非线性约瑟夫森振荡的观察限制在光子分子形成的两个重叠的微柱蚀刻在半导体微腔（8）。在低密度下，我们观察到两个站点之间的粒子隧穿相干振荡。在高密度下，相互作用淬灭粒子的转移，诱导其中一个微柱中的极化激元的宏观自捕获（9，10）。有限的寿命导致从自陷到π相振荡的动力学转变。我们的研究结果为光子系统中高度非线性区域的实验研究开辟了道路，例如混沌（11-13）或破环分叉（14，15）。
The coupling of two macroscopic quantum states through a tunnel barrier gives rise to Josephson phenomena(1) such as Rabi oscillations(2), the a.c. and d.c. effects(3), or macroscopic self-trapping, depending on whether tunnelling or interactions dominate(4). Nonlinear Josephson physics was first observed in superfluid helium(5) and atomic condensates(6,7), but it has remained inaccessible in photonic systems because it requires large photon-photon interactions. Here we report on the observation of nonlinear Josephson oscillations of two coupled polariton condensates confined in a photonic molecule formed by two overlapping micropillars etched in a semiconductor microcavity(8). At low densities we observe coherent oscillations of particles tunnelling between the two sites. At high densities, interactions quench the transfer of particles, inducing the macroscopic self-trapping of polaritons in one of the micropillars(9,10). The finite lifetime results in a dynamical transition from self-trapping to oscillations with pi phase. Our results open the way to the experimental study of highly nonlinear regimes in photonic systems, such as chaos(11-13) or symmetry-breaking bifurcations(14,15).