van de Groep Jorik, Li Qitong, Song Jung-Hwan, Kik Pieter G, Brongersma Mark L
Geballe Laboratory for Advanced Materials, Stanford University, Stanford, USA.
Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Amsterdam, The Netherlands.
Nanophotonics. 2023 Jun 20;12(16):3291-3300. doi: 10.1515/nanoph-2023-0193. eCollection 2023 Aug.
Exciton resonances in monolayer transition-metal dichalcogenides (TMDs) provide exceptionally strong light-matter interaction at room temperature. Their spectral line shape is critical in the design of a myriad of optoelectronic devices, ranging from solar cells to quantum information processing. However, disorder resulting from static inhomogeneities and dynamical fluctuations can significantly impact the line shape. Many recent works experimentally evaluate the optical properties of TMD monolayers placed on a substrate and the line shape is typically linked directly to the material's quality. Here, we highlight that the interference of the substrate and TMD reflections can strongly influence the line shape. We further show how basic, room-temperature reflection measurements allow investigation of the quantum mechanical exciton dynamics by systematically controlling the substrate reflection with index-matching oils. By removing the substrate contribution with properly chosen oil, we can extract the excitonic decay rates including the quantum mechanical dephasing rate. The results provide valuable guidance for the engineering of exciton line shapes in layered nanophotonic systems.
单层过渡金属二硫属化物（TMDs）中的激子共振在室温下提供了异常强的光与物质相互作用。它们的光谱线形在从太阳能电池到量子信息处理等众多光电器件的设计中至关重要。然而，由静态不均匀性和动态涨落导致的无序会显著影响线形。许多近期的工作通过实验评估了置于衬底上的TMD单层的光学性质，并且线形通常直接与材料质量相关联。在此，我们强调衬底和TMD反射的干涉会强烈影响线形。我们进一步展示了如何通过使用折射率匹配油系统地控制衬底反射，利用基本的室温反射测量来研究量子力学激子动力学。通过用适当选择的油去除衬底贡献，我们可以提取包括量子力学退相速率在内的激子衰减率。这些结果为层状纳米光子系统中激子线形的工程设计提供了有价值的指导。
