论文标题
单层Mose $ _2 $和WSE $ _2 $在同质限制中的相干动力和映射
Coherent dynamics and mapping of excitons in single-layer MoSe$_2$ and WSe$_2$ at the homogeneous limit
论文作者
论文摘要
我们在Mose $ _2 $的单层和WSE $ _2 $的单层中执行激子的连贯的非线性光谱，这些非线性光谱封装在Hexagonal Boron Nitride之间。使用四波混合显微镜，我们鉴定了几乎无疾病的区域，以同质极限产生激子光学响应。集中在此类区域上，我们测量了激子均匀扩展，这是环境因素，即温度和激子密度的函数。利用FWM成像，我们发现在这样的位置，可以观察到激发态的非线性吸收及其相干耦合。使用WSE $ _2 $异质结构，我们推断出激子2S状态的连贯性和密度动力学。由于其辐射寿命的增加，在低温下，2s状态的脱位比1S转变更长。在扫描跨数十微米的各种异质结构的同时，我们得出的结论是，主要由应变变化引起的疾病仍将在空间上产生不均匀的拓宽。
We perform coherent nonlinear spectroscopy of excitons in single-layers of MoSe$_2$ and WSe$_2$ encapsulated between thin films of hexagonal boron nitride. Employing four-wave mixing microscopy we identify virtually disorder free areas, generating exciton optical response at the homogeneous limit. Focussing on such areas, we measure exciton homogeneous broadening as a function of environmental factors, namely temperature and exciton density. Exploiting FWM imaging, we find that at such locations, nonlinear absorption of the exciton excited states and their coherent couplings can be observed. Using the WSe$_2$ heterostructure, we infer coherence and density dynamics of the exciton 2S state. Owing to its increased radiative lifetime, at low temperatures, the dephasing of the 2S state is longer than of the 1S transition. While scanning various heterostructures across tens of micrometers, we conclude that the disorder, principally induced by strain variations, remain to be present creating spatially varying inhomogeneous broadening.
