Manipulating valley-polarized photoluminescence of MoS2 monolayer at off resonance wavelength with a double-resonance strategy

Abstract

The intrinsic spin-valleys in monolayer transition metal dichalcogenides make them promising for exploring new-generation valleytronic and spintronic devices. However, it is very challenging to detect and manipulate a specific valley with off resonance electromagnetic fields at room temperature due to their ultrashort lifetimes and phonon-assisted intervalley scattering. Here, utilizing the sputtering and the focused ion beam milling methods, we fabricate a quasi-three-dimensional chiral microstructure using molybdenum disulfide. Based on chirality and double plasmonic resonances, we realize off resonance wavelength control of valley-polarized photoluminescence at room temperature. Furthermore, we find that the chiral field excitation enhancement (13) and chiral quantum yield amplification (1.35 times) contribute to the huge differences in the photoluminescence of valleys. These results reported here may pave the way for further development of on-chip photonic integration of two-dimensional materials.