Routing valley exciton emission of a WS2 monolayer via delocalized Bloch modes of in-plane inversion-symmetry-broken photonic crystal slabs

• 作者: Jiajun Wang Han Li Yating Ma Maoxiong Zhao Wenzhe Liu Bo Wang Shiwei Wu Xiaohan Liu Lei Shi Tian Jiang Jian Zi
• 来源期刊: 光：科学与应用（英文版）
• 年，卷（期）: 2020,（5）
• 所属期刊栏目: Original Articles
• 页码范围: 1446-1453
• 页数: 8页
• 语种: 英文

摘要

The valleys of two-dimensional transition metal dichalcogenides (TMDCs) offer a new degree of freedom for information processing. To take advantage of this valley degree of freedom, on the one hand, it is feasible to control valleys by utilizing different external stimuli, such as optical and electric fields. On the other hand, nanostructures are also used to separate the valleys by near-field coupling. However, for both of the above methods, either the required low-temperature environment or low degree of coherence properties limit their further applications. Here, we demonstrate that all-dielectric photonic crystal (PhC) slabs without in-plane inversion symmetry (C2 symmetry) can separate and route valley exciton emission of a WS2 monolayer at room temperature. Coupling with circularly polarized photonic Bloch modes of such PhC slabs, valley photons emitted by a WS2 monolayer are routed directionally and are efficiently separated in the far field. In addition, far-field emissions are directionally enhanced and have long-distance spatial coherence properties.