Imaging of Plasmonic Chiral Radiative Local Density of States with Cathodoluminescence Nanoscopy

Abstract

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 WSe2 nanodisks (NDs) at chiral radiative LDOS hot-spots and forming ND/Au hybrid nanostructures, the chiral radiative properties of WSe2 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.

Local Optical Chirality Induced by Near-Field Mode Interference in Achiral Plasmonic Metamolecules

“…We obtained well-defined nanostructures with reproducible sizes and gap distances (see the SEM image in Figure 4a). Previous reports on the experimental characterization of the optical near-field chirality relied on near-field optical microscopy (SNOM) [17,26,27] and cathodoluminescence [20]. Here, we use a photosensitive this technique is about 20 nm [28] and can map plasmonic hot spots [29].…”

Light‐Controlled Near‐Field Energy Transfer in Plasmonic Metasurface Coupled MoS2Monolayer

“…[50] Previous studies have reported to explore metal nanostructures in detail by CL detection and mapping with deep-subwavelength resolution precision. [51,52] Here, CL measurements were also performed to explore the radiation mode from the metasurface.…”

Enhanced directional emission of monolayer tungsten disulfide (WS2) with robust linear polarization via one-dimensional photonic crystal (PhC) slab

“…However, the quantum yield of untreated monolayer TMDCs turns to be rather low (typically less than 1%) at room temperature, resulting in a weak photoluminescence (PL) behavior [8,14,15]. Various approaches have been developed and introduced to reinforce the emission of monolayer TMDCs, including integration of noble metal nanoantenna via localized surface plasmon [16][17][18][19][20][21][22][23][24], chemical modification [14,25] and construction of heterostructures with additional high-absorption perovskite materials [26,27]. While some improvements have been observed, there are some realistic limitations using these methods.…”