Department of Physics , Chalmers University of Technology , 412 96 , Göteborg , Sweden.
Centre of New Technologies , University of Warsaw , Banacha 2c , 02-097 Warsaw , Poland.
Nano Lett. 2018 Mar 14;18(3):1777-1785. doi: 10.1021/acs.nanolett.7b04965. Epub 2018 Feb 6.
Formation of dressed light-matter states in optical structures, manifested as Rabi splitting of the eigen energies of a coupled system, is one of the key effects in quantum optics. In pursuing this regime with semiconductors, light is usually made to interact with excitons, electrically neutral quasiparticles of semiconductors; meanwhile interactions with charged three-particle states, trions, have received little attention. Here, we report on strong interaction between localized surface plasmons in silver nanoprisms and excitons and trions in monolayer tungsten disulfide (WS). We show that the plasmon-exciton interactions in this system can be efficiently tuned by controlling the charged versus neutral exciton contribution to the coupling process. In particular, we show that a stable trion state emerges and couples efficiently to the plasmon resonance at low temperature by forming three bright intermixed plasmon-exciton-trion polariton states. Our findings open up a possibility to exploit electrically charged polaritons at the single nanoparticle level.
在光学结构中形成被修饰的物质状态，表现为耦合系统本征能量的拉比分裂，是量子光学中的关键效应之一。在半导体中追求这种状态时，光通常与激子相互作用，激子是半导体的电中性准粒子；同时，与带电的三体态——三电子态的相互作用却很少受到关注。在这里，我们报告了银纳米棱镜中的局域表面等离激元与单层二硫化钨中的激子和三电子态之间的强相互作用。我们表明，通过控制耦合过程中带电激子与中性激子的贡献，可以有效地调节该体系中的等离激元-激子相互作用。特别是，我们表明通过形成三个明亮的混合等离激元-激子-三电子态极化激元，可以在低温下稳定地出现三电子态，并有效地与等离激元共振耦合。我们的发现为在单个纳米颗粒水平上利用带电极化激元开辟了可能性。
