Liu Xiaoze, Bao Wei, Li Quanwei, Ropp Chad, Wang Yuan, Zhang Xiang
NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2017 Jul 14;119(2):027403. doi: 10.1103/PhysRevLett.119.027403.
Monolayer transition metal dichalcogenides (TMD) with confined 2D Wannier-Mott excitons are intriguing for the fundamental study of strong light-matter interactions and the exploration of exciton polaritons at high temperatures. However, the research of 2D exciton polaritons has been hindered because the polaritons in these atomically thin semiconductors discovered so far can hardly support strong nonlinear interactions and quantum coherence due to uncontrollable polariton dynamics and weakened coherent coupling. In this work, we demonstrate, for the first time, a precisely controlled hybrid composition with angular dependence and dispersion-correlated polariton emission by tuning the polariton dispersion in TMD over a broad temperature range of 110-230 K in a single cavity. This tamed polariton emission is achieved by the realization of robust coherent exciton-photon coupling in monolayer tungsten disulphide (WS_{2}) with large splitting-to-linewidth ratios (>3.3). The unprecedented ability to manipulate the dispersion and correlated properties of TMD exciton polaritons at will offers new possibilities to explore important quantum phenomena such as inversionless lasing, Bose-Einstein condensation, and superfluidity.
具有受限二维万尼尔 - 莫特激子的单层过渡金属二卤化物（TMD）对于强光 - 物质相互作用的基础研究以及高温下激子极化激元的探索具有重要意义。然而，二维激子极化激元的研究受到了阻碍，因为迄今为止在这些原子级薄的半导体中发现的极化激元由于不可控的极化激元动力学和减弱的相干耦合，几乎无法支持强非线性相互作用和量子相干。在这项工作中，我们首次通过在单个腔体内将TMD中的极化激元色散在110 - 230 K的宽温度范围内进行调谐，展示了一种具有角度依赖性和色散相关极化激元发射的精确控制的混合组合物。这种可控的极化激元发射是通过在具有大分裂与线宽比（>3.3）的单层二硫化钨（WS₂）中实现稳健的相干激子 - 光子耦合来实现的。前所未有的随意操纵TMD激子极化激元色散和相关特性的能力为探索诸如无反转激光、玻色 - 爱因斯坦凝聚和超流性等重要量子现象提供了新的可能性。
