Key Laboratory of Nanoscale Measurement and Standardization , National Center for Nanoscience and Technology , Beijing 100190 , China.
Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China.
Nano Lett. 2019 Feb 13;19(2):775-780. doi: 10.1021/acs.nanolett.8b03850. Epub 2019 Jan 3.
Chiral light-matter interactions as an emerging aspect of quantum optics enable exceptional physical phenomena and advanced applications in nanophotonics through the nanoscale exploitation of photon-emitter interactions. The chiral radiative properties of quantum emitters strongly depend on the photonic environment, which can be drastically altered by plasmonic nanostructures with a high local density of states (LDOS). Hence, precise knowledge of the chiral photonic environment is essential for manipulating the chirality of light-matter interactions, which requires high resolution chiral characterization techniques. In this work, chiral radiative LDOS distributions of single plasmonic nanostructures that directly govern the chiral radiative spontaneous decay of quantum emitters are imaged at the nanoscale by using cathodoluminescence nanoscopy, enabling precise and highly efficient control of chiral photon emission for chiroptical technologies. Radiative LDOS hot-spots with the chirality larger than 93% are obtained by properly designing chiral plasmonic modes of Au nanoantennas. After fabricating monolayered WSe nanodisks (NDs) at chiral radiative LDOS hot-spots and forming ND/Au hybrid nanostructures, the chiral radiative properties of WSe NDs are significantly modified, leading to chiral photoluminescence. Our experimental concept and method provide an effective way to characterize and manipulate chiral light-matter interactions at the nanoscale, facilitating future applications in chiral quantum nanophotonics such as single-photon sources and light emission devices.
手性光物质相互作用是量子光学的一个新兴方面，通过在纳米尺度上利用光子-发射器相互作用，在纳米光子学中实现了特殊的物理现象和先进的应用。量子发射器的手征辐射特性强烈依赖于光子环境，而等离子体纳米结构具有高密度的局域态密度（LDOS），可以极大地改变光子环境。因此，精确了解手征光子环境对于操纵光物质相互作用的手征性至关重要，这需要高分辨率的手征特性分析技术。在这项工作中，通过使用电子背散射衍射纳米显微镜，在纳米尺度上直接对单等离子体纳米结构的手征辐射 LDOS 分布进行成像，从而对量子发射器的手征辐射自发衰减进行成像，实现了对手征光子发射的精确和高效控制，用于手征光学技术。通过合理设计 Au 纳米天线的手征等离子体模式，可以获得手征性大于 93%的辐射 LDOS 热点。在手征辐射 LDOS 热点处制备单层 WSe 纳米盘（NDs）并形成 ND/Au 杂化纳米结构后，WSe NDs 的手征辐射特性得到了显著修饰，从而产生手征光致发光。我们的实验概念和方法为在纳米尺度上表征和操纵手征光物质相互作用提供了一种有效途径，为手征量子纳米光子学中的应用，如单光子源和发光器件，提供了便利。
