Nanoscale Valley Modulation by Surface Plasmon Interference

Abstract

Excitons in two-dimensional (2D) materials have attracted the attention of the community to develop improved photoelectronic devices. Previous reports are based on direct excitation where the out-of-plane illumination projects a uniform single-mode light spot. However, because of the optical diffraction limit, the minimal spot size is a few micrometers, inhibiting the precise manipulation and control of excitons at the nanoscale level. Herein, we introduced the in-plane coherent surface plasmonic interference (SPI) field to excite and modulate excitons remotely. Compared to the out-of-plane light, a uniform in-plane SPI suggests a more compact spatial volume and an abundance of mode selections for a single or an array of device modulation. Our results not only build up a fundamental platform for operating and encoding the exciton states at the nanoscale level but also provide a new avenue toward all-optical integrated valleytronic chips for future quantum computation and information applications.

Plexcitonics: plasmon–exciton coupling for enhancing spectroscopy, optical chirality, and nonlinearity

“…[104][105][106] More and more interesting experimental and theoretical phenomena resulting from the interactions between hybrid complexes of chiral molecules and plasmonic nanostructures have attracted great attention and extensive research. [107][108][109] Research progress has focused on developing new chiral plexcitonic nanostructures with enhanced optical chirality and coupling, 110,111 and have solved several important issues, including the selective detection of chiral molecules and observation of circularly polarized emission using plexcitonic systems. 112,113 Lan et al devoted DNA-templated strategies to manipulating chiral self-assembly of achiral chromophores on Au NP surfaces with tuned exciton transitions, achieving strongly enhanced molecular CD signal of chromophores and an induced plasmonic CD signals at visible wavelengths.…”

Multifunctional light-field modulation based on hybrid nonlinear metasurfaces

“…To overcome the limitations in the development of valleytronics, researchers have conducted forward-looking works by combining TMDCs with nanostructures. [186][187][188] The propagation characteristics of the surface plasmon polaritons (SPP) can be utilized to separate valley excitons into different directions by introducing the photonic spin Hall effect (PSHE). [189][190][191][192] In 2018, Kuipers et al coupled the valley pseudospin in WS 2 with the transverse optical spin angular momentum (t-OSAM) induced by SPP in Ag nanowires, achieving the separation of valley excitons at room temperature.…”

Hybrid Metasurfaces of Plasmonic Lattices and 2D Materials

“…[ 25,32 ] Therefore, integrating 2D materials with ordered plasmonic structures to form hybrid metasurfaces have emerged as a new research theme that shows exceptional promise in light‐matter interactions and device developments. [ 30,33–35 ] There are inspiring reviews on the physics, fabrication, and application of various plasmonic nanostructures and metasurfaces, [ 31,36–42 ] but a comprehensive review on the rapid development of plasmonic‐2D materials hybrid metasurface is still lacking. In this review, we first lay the foundation by introducing the basics of plasmonic modes and optical properties of 2D materials.…”