Single-Crystalline Gold Nanodisks on WS2 Mono- and Multilayers for Strong Coupling at Room Temperature
Single-Crystalline Gold Nanodisks on WS2 Mono- and Multilayers for Strong Coupling at Room Temperature
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DOI：
10.1021/acsphotonics.8b01766
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发表时间：
2019-04-01
期刊：
影响因子：
7
通讯作者：
Stenger, Nicolas
中科院分区：
文献类型：
--
作者：
Geisler, Mathias;Cui, Ximin;Stenger, Nicolas
在室温下将光与物质相互作用工程化至强耦合状态是现代纳米光子学的基石之一。实现这一目标可以为量子信息处理、量子光源甚至量子计量等潜在应用提供新平台。过渡金属二硫属化物 (TMDC) 等层状材料，特别是二硫化钨 (WS2)，具有与半导体量子点相当的强偶极矩，但前者还表现出 1.6 个大的激子结合能，从而使 TMDC 成为探索环境条件下光与物质相互作用的合适候选者。此外，TMDC 与等离子体纳米腔的结合，将光严格限制在纳米尺度，最近已成为在室温下实现等离子体激子和激子之间强耦合的合适平台。在这里，我们使用超薄单晶金纳米盘，其具有与单层 WS2 中激子偶极矩对齐的大面内电偶极矩。通过执行散射和反射光谱，我们证明了室温下的强耦合，拉比分裂类似于 408 meV。此外，当这些纳米盘的等离激元共振与几层WS2耦合时，观察到类似于175 meV的拉比分裂，相对于单层配置大幅增加了62%。因此，我们的结果表明，与 WS2 耦合的超薄单晶金纳米盘构成了探索强耦合状态下光与物质相互作用的一个有吸引力的平台。
Engineering light-matter interactions up to the strong-coupling regime at room temperature is one of the cornerstones of modern nanophotonics. Achieving this goal could enable new platforms for potential applications such as quantum information processing, quantum light sources, and even quantum metrology. Layered materials like transition metal dichalcogenides (TMDCs) and, in particular, tungsten disulfide (WS2), possess strong dipole moments which are comparable to semiconductor-based quantum dots, but the former also exhibit 1.6 large exciton binding energies, thereby making TMDCs suitable candidates for exploring light-matter interactions at ambient conditions. Furthermore, the combination of TMDCs with plasmonic nanocavities, which tightly confine light down to nanometer scale, has recently emerged as a suitable platform for achieving strong coupling between plasmons and excitons at room temperature. Here, we use ultrathin single-crystalline gold nanodisks featuring large in-plane electric dipole moments aligned with the exciton's dipole moments in monolayer WS2. By performing both scattering and reflection spectroscopy, we demonstrate strong coupling at room temperature with a Rabi splitting of similar to 408 meV. In addition, when the plasmonic resonance of these nanodisks is coupled with few-layer WS2, a Rabi splitting of similar to 175 meV is observed, with a major increase of 62% relative to the monolayer configuration. Our results therefore suggest that ultrathin single-crystalline gold nanodisks coupled to WS2 constitute an attractive platform to explore light-matter interactions in the strong-coupling regime.