posted on 2024-01-29, 15:38authored byJie Zhong, Jun-Yu Li, Jin Liu, Yifan Xiang, He Feng, Renming Liu, Wei Li, Xue-Hua Wang
Engineering room-temperature strong coupling of few-exciton
in
transition-metal dichalcogenides (TMDCs) with plasmons promises to
construct compact and high-performance quantum optical devices. But
it remains unimplemented due to their in-plane excitons. Here, we
demonstrate the strong coupling of few-exciton within 10 in monolayer
WS2 with the plasmonic mode with a large tangential component
of the electric field tightly trapped around the sharp corners of
an Au@Ag nanocuboid, the fewest number of excitons observed in the
TMDC family so far. Furthermore, we for the first time report a significant
deviation with a relative difference of up to 100.6% between the spectrum
and eigenlevel splitting dispersions, which increases with decreasing
coupling strength. It is also shown that the coupling strength obtained
by the conventional concept of both being equal to the measured spectrum
splitting is markedly overestimated. Our work enriches the understanding
of strong light–matter interactions at room temperature.