Light-matter coupling with two-dimensional tellurides

该项目重点研究由半导体2H相MoTe2和MoWTe2组成的原子薄过渡金属二硫化物层的基本多体激发光学性质。我们将研究先进的光-物质耦合，特别强调在这些单层中出现的激子-极化子的形成，谷选择动态散射和凝聚，通过将它们单层嵌入定制设计的介电微腔中。第一个目标是通过不同的光谱技术研究2H-MoTe2和2H-MoWTe2单层中许多体态和基本激发的光学性质。通过优化样品制备技术，衬底和封盖程序，我们将系统地提高材料的光学质量。我们将进一步探索三元2H-MoWTe2层以及应变和介电工程2H-MoTe2的光学跃迁在多大程度上可以达到1.3 μ m的重要电信窗口。第二个目标是利用原子薄的MoTe2和MoWTe2实现在近红外光谱范围内工作的室温极化器件平台。随着用于MoSe2和WSe2集成的低模体积和高质量因子>103的介电微腔的出现，我们将推动该技术进入1.3µm左右的重要光谱范围。一旦建立了Mo(W)Te2单层与光学腔共振之间的强耦合机制，将详细探讨极化子的动态弛豫和散射效应、本征非线性和最终态玻色子刺激导致的动态极化子凝聚。基于MoTe2的极化非线性器件，特别是在电信窗口中操作的器件是难以捉摸的。除了对2H-MoTe2和2H-MoWTe2单层的物理和光学性质有更深入的了解外，如本项目所预见的，在1300 nm处成功实现极化子凝聚体，将是实现基于最终薄增益材料的超低阈值纳米激光器的重大突破。

The project focuses on fundamental investigations of the optical properties of elementary manybody excitations in atomically thin transition-metal dichalcogenide layers, composed of MoTe2 and MoWTe2 in their semiconducting 2H phase. We will study advanced light-matter coupling, with a particular emphasize on the formation, valley-selective dynamic scattering and condensation of exciton-polaritons, emerging in these monolayers, by embedding them monolayers in custom-designed dielectric microcavities. The first objective is to investigate the optical properties of many body-states and fundamental excitations in 2H-MoTe2 and 2H-MoWTe2 monolayers via different spectroscopy techniques. By optimizing sample preparation techniques, substrates, and capping procedures, we will systematically improve the optical quality of the materials. We will furthermore explore, to what extent the optical transitions in the ternary 2H-MoWTe2 layers, as well as strain- and dielectrically engineered 2H-MoTe2 can reach the important telecom window at 1.3 µm. The second objective is to implement a room-temperature polaritonic device-platform operating in the near- infrared spectral range utilizing atomically thin MoTe2 and MoWTe2.While dielectric microcavities with low mode volumes and high-quality factors >103 for the integration of MoSe2 and WSe2 recently became available, we will push forward this technology to enter the important spectral range around 1.3 µm. Once the strong coupling regime between Mo(W)Te2 monolayers and the optical cavity resonance is established, dynamic relaxation and scattering effects of polaritons, intrinsic non-linearities and the final state bosonic stimulation leading to dynamical polariton condensation , will be explored in detail. MoTe2 based polaritonic nonlinear devices, in particular operated in the Telecommunication window are elusive. Apart from gaining a deeper understanding in the physics and optical properties of 2H-MoTe2 and 2H-MoWTe2 monolayers, a successful implementation of polariton condensates at 1300 nm, as foreseen in this project, would compose a major breakthrough towards the implementation of ultra-low threshold nanolasers based on ultimately thin gain materials.