Mechanisms of blueshifts in organic polariton condensates
Mechanisms of blueshifts in organic polariton condensates
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DOI：
10.1038/s42005-019-0278-6
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发表时间：
2020-01-22
影响因子：
5.5
通讯作者：
Lagoudakis, Pavlos
中科院分区：
文献类型：
--
作者：
Yagafarov, Timur;Sannikov, Denis;Lagoudakis, Pavlos
无机半导体微腔中激子-极化激元的玻色-爱因斯坦凝聚体由于其激子成分而具有很强的粒子间相互作用。这种相互作用在系统的非线性动力学中起着至关重要的作用，并且可以被看作是极化激元态的能量蓝移。然而，在强耦合的有机微腔中的Frenkel激子的局部性质排除了粒子间库仑交换相互作用，从而改变了非线性和蓝移的机制。在这份报告中，我们揭开了有机极化激元凝聚体中蓝移的起源。我们研究了可能的贡献：腔内光学克尔效应，增益诱导的频率拉动，极化激元相互作用和相关的弱耦合和强耦合分子的光学跃迁的饱和效应。我们的结论是，在有机极化激元凝聚的蓝移产生的饱和效应和分子间的能量迁移的相互作用。我们的模型预测了在极化激元凝聚阈值下，发射能量和线性偏振度的阶跃式增加。尽管科学技术的发展日新月异，但人们对有机极化激元体系的非线性现象的认识却一直很模糊。这项研究揭示了有机极化激元凝聚体中无所不在的能量转移机制，强调了此类系统中的非线性动力学。
Bose-Einstein condensates of exciton-polaritons in inorganic semiconductor microcavities are known to possess strong interparticle interactions attributed to their excitonic component. The interactions play a crucial role in the nonlinear dynamics of such systems and can be witnessed as the energy blueshifts of polariton states. However, the localised nature of Frenkel excitons in strongly coupled organic microcavities precludes interparticle Coulomb exchange-interactions that change mechanisms of the nonlinearity and blueshifts accordingly. In this report, we unravel the origins of blueshifts in organic polariton condensates. We examine the possible contributions: intracavity optical Kerr-effect, gain-induced frequency-pulling, polariton interactions and effects related to saturation of optical transitions for weakly- and strongly-coupled molecules. We conclude that blueshifts in organic polariton condensates arise from the interplay of the saturation effects and intermolecular energy migration. Our model predicts the commonly observed step-like increase of both the emission energy and degree of linear polarization at the polariton condensation threshold.Despite rapid scientific and technological development of organic polariton systems, the understanding of their nonlinear phenomena has eluded the community. This study unravels the mechanisms of the omnipresent energy shifts in organic polariton condensates, underlining the nonlinear dynamics in such systems.