Xiang Bo, Li Yiliu, Spencer M S, Dai Yanan, Bai Yusong, Basov Dmitri N, Zhu X-Y
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Department of Physics and Astronomy, Columbia University, New York, New York 10027, USA.
J Chem Phys. 2024 Apr 28;160(16). doi: 10.1063/5.0202341.
An exciton-polariton condensate is a hybrid light-matter state in the quantum fluid phase. The photonic component endows it with characters of spin, as represented by circular polarization. Spin-polarization can form stochastically for quasi-equilibrium exciton-polariton condensates at parallel momentum vector k|| ∼ 0 from bifurcation or deterministically for propagating condensates at k|| > 0 from the optical spin-Hall effect (OSHE). Here, we report deterministic spin-polarization in exciton-polariton condensates at k|| ∼ 0 in microcavities containing methylammonium lead bromide perovskite (CH3NH3PbBr3) single crystals under non-resonant and linearly polarized excitation. We observe two energetically split condensates with opposite circular polarizations and attribute this observation to the presence of strong birefringence, which introduces a large OSHE at k|| ∼ 0 and pins the condensates in a particular spin state. Such spin-polarized exciton-polariton condensates may serve not only as circularly polarized laser sources but also as effective alternatives to ultracold atom Bose-Einstein condensates in quantum simulators of many-body spin-orbit coupling processes.
激子极化激元凝聚体是处于量子流体相的一种混合光物质态。光子成分赋予它自旋特性，以圆偏振表示。对于在平行动量矢量(k_{\parallel}\sim0)处通过分岔形成的准平衡激子极化激元凝聚体，自旋极化可随机形成；而对于在(k_{\parallel}>0)处传播的凝聚体，自旋极化可通过光学自旋霍尔效应（OSHE）确定性地形成。在此，我们报道了在包含甲基溴化铅钙钛矿（(CH_3NH_3PbBr_3)）单晶的微腔中，在非共振和线性偏振激发下，(k_{\parallel}\sim0)处的激子极化激元凝聚体中的确定性自旋极化。我们观察到具有相反圆偏振的两个能量分裂的凝聚体，并将此观察结果归因于强双折射的存在，强双折射在(k_{\parallel}\sim0)处引入了大的光学自旋霍尔效应，并将凝聚体固定在特定的自旋态。这种自旋极化的激子极化激元凝聚体不仅可作为圆偏振激光源，还可作为多体自旋轨道耦合过程量子模拟器中超冷原子玻色 - 爱因斯坦凝聚体的有效替代物。
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