Rydberg Exciton Interaction Dynamics

里德伯激子相互作用动力学

• 批准号: 316133134
• 负责人: Professor Dr. Marc Alexander Aßmann
• 金额: --
• 依托单位: Lehrstuhl für Experimentelle Physik II
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/316133134?language=en
• 关键词: Rydberg; Exciton; Interaction; Dynamics

Rydberg excitons are the solid state equivalent to Rydberg atoms and share many of their fascinating properties, for example huge interactions among each other up to the point of Rydberg blockade. They may also be used as sensitive probes for the presence of freecarriers, which cause similar blockade effects termed Plasma blockade already at densities of less than 0.01 electron-hole-pairs per cubic micrometer. For subsequent experiments aimed at harnessing Rydberg blockade, it is of fundamental importance to be able todistinguish between these two blockade mechanisms and to create them deterministically. In comparison to Rydberg atoms, the semiconductor surrounding causes faster and more complex carrier and population dynamics which need to be understood in detail first.For example, it is expected that free carriers may form bound exciton states quickly, while excitons may be ionized e.g. by interaction with phonons, so for long times, in general a mixture of both Blockade mechanisms is expected. Therefore, the main aim of the presentprojct lies in gaining a deeper understanding of the complex population dynamics via time-resolved and spatially resolved spectroscopy. To this end, this project aims at investigating timeresolved Rydberg blockade with the help of a tailored modulator that creates Fourier-limited pulses with a duration of approximately 500 PS to 1 ns. This will allow us to perform pump-probe experiments, which will shed light on the rate of exciton formation from plasma, theionization rate of Rydberg excitons, their relaxation towards lowerenergy states and the Auger-assisted formation of plasma from paraexcitons. Further, we will focus on propagation effects and spatially resolved measurements of blockade efficiency to gain a deeper understanding of the spatial dependence of the interaction potential between Rydberg excitons and to understand whether dispersion effects resulting from varying propagation velocities ofpolaritons with different principal quantum numbers result in interactions that vary at different positions inside the crystal or at different times. Finally, we will also investigate the influence of dipoleforbidden excitons on their optically active counterparts. Here, we willfocus on S- and D-excitons, which have wavefunctions with a shape that differs significantly from that of P-excitons, which implies that the interaction potential may be rather complicated. Here we will perform two-photon absorption and second-harmonic spectroscopy todeliberately excite the dipole-forbidden states due to the altered selection rules for two-photon absorption. In summary, the main aim of the present project lies in gaining a detailed understanding of the population dynamics of the several exciton and free-carrier states inCu2O and their interactions.

里德伯激子是固体状态下的里德伯原子，并分享他们的许多迷人的性质，例如巨大的相互作用，彼此之间的里德伯封锁点。它们也可以用作自由载流子存在的敏感探针，自由载流子在小于每立方微米0.01个电子空穴对的密度下已经引起类似的称为等离子体阻断的阻断效应。对于随后旨在利用里德伯阻断的实验，能够区分这两种阻断机制并确定性地创建它们是至关重要的。与里德伯原子相比，半导体周围的环境导致更快和更复杂的载流子和布居动力学，这需要首先详细了解。例如，预计自由载流子可以快速形成束缚激子态，而激子可以通过例如与声子的相互作用而电离，因此在很长一段时间内，通常预期两种封锁机制的混合物。因此，本项目的主要目的在于通过时间分辨和空间分辨光谱学更深入地了解复杂的种群动力学。为此，该项目的目的是调查时间分辨的里德伯封锁的帮助下，定制的调制器，创建傅立叶限制脉冲的持续时间约为500 PS至1 ns。这将使我们能够进行泵浦探测实验，这将揭示从等离子体中激子形成的速率，里德伯激子的电离速率，它们向低能态的弛豫以及从准激子形成等离子体的俄歇辅助。此外，我们将专注于传播效应和空间分辨的测量封锁效率，以获得更深入的理解里德伯激子之间的相互作用势的空间依赖性，并了解是否色散效应导致不同的传播速度ofpolaritons与不同的主量子数的结果在不同的相互作用，在晶体内的不同位置或在不同的时间。最后，我们也将研究偶极禁戒激子对光学活性激子的影响。在这里，我们将集中在S-和D-激子，它们的波函数的形状与P-激子的波函数的形状显著不同，这意味着相互作用势可能相当复杂。在这里，我们将进行双光子吸收和二次谐波光谱故意激发偶极禁戒态，由于双光子吸收的选择规则的改变。总之，本项目的主要目的在于获得详细的了解的几个激子和自由载流子态inCu 2 O和它们的相互作用的人口动态。