Single vortex-antivortex pair in an exciton-polariton condensate
Single vortex-antivortex pair in an exciton-polariton condensate
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DOI：
10.1038/nphys1841
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发表时间：
2011-02-01
期刊：
影响因子：
19.6
通讯作者：
Yamamoto, Yoshihisa
中科院分区：
文献类型：
--
作者：
Roumpos, Georgios;Fraser, Michael D.;Yamamoto, Yoshihisa
在非零温度下的均匀二维系统中，不可能有无限范围的有序（1，2）。然而，对于玻色液体在这样的条件下，超流相预测（3-5）。在这种超流状态下，束缚涡-反涡对主导着热力学和相相干性质。据信，当描述其有序状态的参数具有两个自由度时，几个系统共享这种行为（6）。这一理论已经在其中一些实验中得到验证（7-12），但是还没有直接的实验观测到包含一个束缚涡旋-反涡旋对的准凝聚体。在这里，我们提出了一个实验技术，可以确定一个单一的涡旋-反涡旋对在二维激子极化激元凝聚。该对是通过泵浦激光的不均匀光斑轮廓产生的，并且在使用迈克尔逊干涉法获得的时间积分相位图中被揭示。基于开放耗散Gross-Pitaevskii方程的数值模拟表明，与原子凝聚体相比，这种非平衡系统中的电子对演化明显不同（13）。
In a homogeneous two-dimensional system at non-zero temperature there can be no ordering of infinite range(1,2). However, for a Bose liquid under such conditions, a superfluid phase is predicted(3-5). Bound vortex-antivortex pairs dominate the thermodynamics and phase coherence properties in this superfluid regime. It is believed that several systems share this behaviour when the parameter describing their ordered state has two degrees of freedom(6). This theory has been tested for some of them(7-12), but there has been no direct experimental observation of a quasi-condensate that includes a bound vortex-antivortex pair. Here we present an experimental technique that can identify a single vortex-antivortex pair in a two-dimensional exciton-polariton condensate. The pair is generated through the inhomogeneous spot profile of the pumping laser, and is revealed in the time-integrated phase maps acquired using Michelson interferometry. Numerical modelling based on the open-dissipative Gross-Pitaevskii equation suggests that the pair evolution is distinctly different in this non-equilibrium system compared with atomic condensates(13).