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(C_(2) 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 WS_(2) 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.
基金
supported by the China National Key Basic Research Program(Grant Nos.2016YFA0301103,2016YFA0302000,and 2018YFA0306201)
the National Science Foundation of China(Grant Nos.11774063,11727811 and 91750102,91963212,11804387,11802339,11805276,61805282,61801498,and 11902358)
further supported by the Science and Technology Commission of Shanghai Municipality(Grant Nos.19XD1434600,2019SHZDZX01,and 19DZ2253000)
further supported by the Science Fund for Distinguished Young Scholars of Hunan Province(Grant No.2020JJ2036).
