Bloch Oscillations and Zener Tunneling of Exciton Polariton Condensates in One- and Two-dimensional Lattices

将量子力学的基本概念转移到高度集成的固态设备上，对于更深入地理解，从而创造基于增强的光-物质相互作用的新技术和设备是最有意义的。这个跨学科的研究项目位于固体物理和光学以及理论物理和实验物理之间的边界上。它侧重于将量子力学的基本概念转移到激子-极化激子系统。激子-极化子是由电磁场(光子)与物质的激发态(激子)强耦合而产生的准粒子。该项目旨在实验实现和观察非常基本的现象，如布洛赫振荡和齐纳隧穿，这些现象与量子粒子(包括光子)在受外部驱动力的周期性结构中的传播直接相关。激子-极化子系统的特殊性质将首次允许对二维布洛赫振荡进行详细分析。多体相互作用引起的激子-极化子的固有非线性也将使我们更深入地了解令人着迷的超流物理。该项目包括理论研究(耶拿大学)和实验研究(维尔茨堡大学)，汇集了光学布洛赫振荡和激子-极化物理领域的两个主要研究小组。我们将研究基于激子-极化子准粒子在共振激发的纳米结构半导体腔中的激发和传播的量子相干现象。我们将首先研究激子-极化子在有效势中的传播，该有效势对应于斜入射激励的耦合波导管阵列。沿导轨传播的场将受到由样品厚度变化引起的横向力的影响。由此产生的Bloch振荡和齐纳隧道效应将被映射到空间伸长，从而允许观察它们的快速动力学。稍后，我们将把注意力转向偏置二维晶格中场的演化，以及由此产生的周期演化，这是现在通过超快光谱检测到的。所有的研究都将在不同的强度下进行，从而监测从线性动力学到非线性动力学的转变和超流动性的开始。我们项目的总体目标是利用结构半导体在纳米尺度上控制激子极化子凝聚体的快速动力学。拟议的研究将同样对非线性光学和现代固体物理领域做出贡献。在本项目中应用和推广的技术平台也将对新型激光器和微腔结构的设计产生重大影响，从而为集成半导体量子光子学提供广阔的领域。

The transfer of basic concepts of quantum mechanics to highly integrated solid state devices is of highest interest for a deeper understanding and hence the creation of new technologies and devices based on enhanced light-matter interaction. This interdisciplinary research project is positioned at the border between solid state physics and optics and between theoretical and experimental physics. It focuses on the transfer of basic concepts of quantum mechanics to an exciton-polariton system. Exciton-polaritons are quasi-particles arising from the strong coupling of an electromagnetic field (photons) to an excited state of matter (excitons). The project aims on the experimental realization and observation of very fundamental phenomena such as Bloch oscillations and Zener tunneling which are directly associated with the propagation of quantum particles (including photons) in periodic structures being subject to external driving forces. The particular nature of the exciton-polariton system will for the first time allow for a detailed analysis of two-dimensional Bloch oscillations. The inherent nonlinearity of the exciton-polaritons caused by many-body interactions will also allow us getting deeper inside into the fascinating physics of superfluidity. The project comprises both theoretical (University of Jena) and experimental (University of Würzburg) investigations, bringing together two of the leading groups in the field of optical Bloch oscillations and exciton-polariton physics. We will investigate quantum coherence phenomena based on the excitation and propagation of exciton-polariton quasi particles in resonantly excited nanostructured semiconductor cavities. We will first study the propagation of exciton-polaritons in an effective potential corresponding to an array of coupled waveguides being excited under oblique incidence. Fields propagating along the guides will be subject to transverse forces induced by thickness variations of the sample. Resulting Bloch oscillations and Zener tunneling will be mapped to a spatial elongation thus allowing for an observation of their fast dynamics. Later we will turn our attention to the evolution of fields in biased two-dimensional lattices and to the resulting periodic evolution which is now detected via ultrafast spectroscopy. All investigations will be performed for varying intensities thus monitoring the transition from linear to nonlinear dynamics and the onset of super fluidity. The overall aim of our project is to control the fast dynamics of exciton polariton condensates on nanoscale dimensions using structured semiconductors. The proposed research will equally contribute to the field of nonlinear optics and modern solid state physics. The technology platform which will be applied and extended in this project will also have a significant impact on the design of new laser and microcavity structures, thus a broad field of integrated semiconductor quantum photonics.