One of the most striking manifestations of quantum coherence in interacting boson systems is superfluidity. Exciton-polaritons in semiconductor microcavities are two-dimensional composite bosons predicted to behave as particular quantum fluids. We report the observation of superfluid motion of polaritons created by a laser in a semiconductor microcavity. Superfluidity is investigated in terms of the Landau criterion and manifests itself as the suppression of scattering from defects when the flow velocity is slower than the speed of sound in the fluid. On the other hand, a Cerenkov-like wake pattern is clearly observed when the flow velocity exceeds the speed of sound. The experimental findings are in excellent quantitative agreement with the predictions based on a generalized Gross-Pitaevskii theory, showing that polaritons in microcavities constitute a very rich system for exploring the physics of non-equilibrium quantum fluids.
Analysis of exciton-polariton condensation under different pumping schemes for 1D and 2D microcavities including the effect of strong correlation between polaritons
Digital-Alloy Bragg Mirrors in High-Q Microcavities for Polariton Lasing
St. Petersburg State University（圣彼得堡国立大学）；Spin Optics Laboratory, St. Petersburg State University（圣彼得堡国立大学旋光实验室）；Nanophotonics Research Center, St. Petersburg State University（圣彼得堡国立大学纳米光子学研究中心）；Abrikosov Center for Theoretical Physics, Moscow Center for Advanced Studies（莫斯科高等研究学院阿布里科索夫理论物理中心）；Russian Quantum Center, Skolkovo, Moscow（俄罗斯量子中心）
Exciton-polaritons are quasiparticles with mixed photon and exciton character that demonstrate rich quantum phenomena, novel optoelectronic devices and the potential to modify chemical properties of materials. Organic semiconductors are of current interest for their room-temperature polariton formation. However, within organic optoelectronic devices, it is often the 'dark' spin-1 triplet excitons that dominate operation. These triplets have been largely ignored in treatments of polariton physics. Here we demonstrate polariton population from the triplet manifold via triplet-triplet annihilatio…
Estimating the conditions for polariton condensation in organic thin-film microcavities
我们研究了在有机量子阱中观察受限二维极化激元气体玻色凝聚的可能性。我们推导出一个合适的参数化模型哈密顿的基础上的腔的几何形状，双激子结合能，和类似的光谱和结构数据。通过转换的总和在$d$维相空间的半经典积分的状态，我们表明，虽然一个理想的2-D玻色气体将不会发生凝聚，与Bogoliubov色散$H(p)\approx s p$接近$p=0$的相互作用的气体将发生玻色凝聚在一个给定的临界密度和温度。我们发现，$T_c/\sqrt{ρ_c}$是敏感的腔的几何形状和双激子结合能。特别是对于强束缚的双激子，Gross-Pitaevskii方程中的非线性相互作用项变为负值，从而得到的基态将是定域孤子态而不是离域玻色凝聚态.
Exciton polaritons in atomically-thin transition metal dichalcogenide crystals (monolayer TMDCs) have emerged as a promising candidate to enable topological transport, ultra-efficient laser technologies, and collective quantum phenomena such as polariton condensation and superfluidity at room temperature. However, integrating monolayer TMDCs into high-quality planar microcavities to achieve the required strong coupling between the cavity photons and the TMDC excitons (bound electron-hole pairs) has proven challenging. Previous approaches to integration had to compromise between various adverse…
Semiconducting single-walled carbon-nanotubes (SWCNTs) are an interesting material for strong-light matter coupling due to their stable excitons, narrow emission in the near infrared and high charge carrier mobilities. Furthermore, they have emerged as quantum light sources as a result of the controlled introduction of luminescent quantum defects (sp$^{3}$-defects) with red-shifted transitions that enable single-photon emission. The complex photophysics of SWCNTs and overall goal of polariton condensation pose the question of how exciton-polaritons are populated and how it might be optimized. …
