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A Single Chiral Nanoparticle Induced Valley Polarization Enhancement
Author(s) -
Kim Sejeong,
Lim YaeChan,
Kim Ryeong Myeong,
Fröch Johannes E.,
Tran Thinh N.,
Nam Ki Tae,
Aharonovich Igor
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202003005
Subject(s) - monolayer , materials science , finite difference time domain method , excitation , polarization (electrochemistry) , nanoparticle , circular polarization , nanophotonics , plasmon , luminescence , exciton , optoelectronics , radiative transfer , molecular physics , nanotechnology , optics , condensed matter physics , physics , chemistry , quantum mechanics , microstrip
Valley polarization is among the most critical attributes of atomically thin materials. However, increasing contrast from monolayer transition metal dichalcogenides (TMDs) has so far been challenging. In this work, a large degree of circular polarization up to 45% from a monolayer WS 2 is achieved at room temperature by using a single chiral plasmonic nanoparticle. The increased contrast is attributed to the selective enhancement of both the excitation and the emission rate having one particular handedness of the circular polarization, together with accelerated radiative recombination of valley excitons due to the Purcell effect. The experimental results are corroborated by the optical simulation using the finite‐difference time‐domain (FDTD) method. Additionally, the single chiral nanoparticle enables the observation of valley‐polarized luminescence with a linear excitation. The results provide a promising pathway to enhance valley contrast from monolayer TMDs and utilize them for nanophotonic devices.