Optical and Quantum Coherence Study of 2D-Material Based Cavity-Enhanced Emitters and Nanolasers

这项拟议的研究旨在了解一系列基本物理问题，涉及a)新兴的单层半导体过渡金属二卤化物，b)纳米发射器和纳米激光器发光的量子光学性质，以及c)基于这种单层半导体的纳米激光器的重要器件物理问题。我们将讨论新的有源材料平台的适宜性和有前景的材料选择，从量子光发射特性的角度展示激光作用，以及提高出耦合效率的器件实现。具有纳米空间的单层半导体集成系统为拟议的研究提供了一个理想的最先进的平台。该团队由三个高素质、高度互补的小组组成，分别专注于2D半导体与量子光场相互作用的微观理论(Jahnke小组，不来梅大学)、纳米激光器的制造和表征(清华大学Ning小组)以及光发射的量子光学相干研究(Reitzenstein小组，柏林理工大学)。组织严密的中德团队非常适合通过从材料准备、器件制造、实验表征和第一性原理理论预测和解释的迭代周期，以最全面和综合的方式研究上述重要问题。从基础科学的角度来看，预期的结果可能会影响我们对二维单分子层半导体发光和增益机制的基本理解，以及纳米发射体的量子相干性质，特别是纳米激光器的阈值行为与量子相干之间的关系。在此背景下，我们将解决一个重要的问题，即如何验证自发辐射耦合因子(β因子)接近于无阈值激光的极限情况下的纳米腔激光器中的激光作用。半导体激光器的这一基本制度将通过对发射的光子统计进行全面的量子光学研究来探索，作为明确识别相干光发射开始的最灵敏的工具。实验和理论的联合工作将致力于通过考虑发射的光子数分布以及输入-输出和线宽依赖关系来更好地理解纳米激光器的发射过程。这里，光子数分布提供了包括更高阶光子关联在内的全部光子统计信息。这项工作将由Reitzenstein小组中非常先进的光子数分辨探测器来实现。从技术角度来看，拟议的研究可能会导致一种新型的纳米光子器件在下一代信息技术中的应用，或者是量子信息技术中的新型器件。

The proposed research aims at the understanding of a series of fundamental physics questions related to a) the emerging monolayer semiconductor transition metal dichalcogenides, b) quantum optical properties of light emission from nanoemitters and nanolasers, as well as c) important device physics issues of nanolasers based on such monolayer semiconductors. We will address the suitability of the new active-material platform and promising material choices, the demonstration of laser action in terms of quantum-optical emission properties, and device realizations with improved outcoupling efficiencies. The integrated system of monolayer semiconductors with nanocavities provides an ideal state-of-the-art platform for the proposed study. The team consists of three well qualified, highly complementary groups specializing in microscopic theory of 2D semiconductors interacting with quantized light field (Jahnke group, University of Bremen), fabrication, and characterization of nanolasers (Ning group, Tsinghua University), and quantum optical coherence study of light emission (Reitzenstein group Technische Universität Berlin), respectively. The well-knit Sino-German team is uniquely suited to investigate the important questions raised above in the most comprehensive and integrative manner through an iterative cycle from materials preparation, device fabrication, experimental characterization, and first-principle theoretical prediction and interpretation. From the fundamental science point of view, the expected results can potentially impact our basic understanding of light emission and gain mechanism in 2D monolayer semiconductors, as well as the nature of quantum coherence of nanoemitters, especially the relationship between threshold behavior of the nanolasers and quantum coherence. In this context, we will address the important issue of how to verify laser action in nanocavity lasers with spontaneous emission coupling factors (beta-factor) approaching unity close to the limiting case of a thresholdless laser. This fundamental regime of semiconductor lasers will be explored by comprehensive quantum optical studies on the photon statistics of emission, acting as the most sensitive tool to unambiguously identify the onset of coherent light emission. The joint experimental and theoretical work will aim at a new level of understanding the emission processes of nanolaser by considering the photon-number distribution of emission in addition to input-output and linewidth dependencies. Here, the photon-number distribution gives access to the full photon statistic including higher order photon correlations. This work will be enabled by highly advanced photon-number resolving detectors in the Reitzenstein group. From the technological point of view, the proposed research could lead to a new type of nanophotonic devices for applications in next generation of information technologies, or novel devices in quantum information technologies.