Giant Out-of-Plane Exciton Emission Enhancement in Two-Dimensional Indium Selenide via a Plasmonic Nanocavity

Abstract

Out-of-plane (OP) exciton-based emitters in twodimensional semiconductor materials are attractive candidates for novel photonic applications, such as radially polarized sources, integrated photonic chips, and quantum communications. However, their low quantum efficiency resulting from forbidden transitions limits their practicality. In this work, we achieve a giant enhancement of up to 34000 for OP exciton emission in indium selenide (InSe) via a designed Ag nanocube-over-Au film plasmonic nanocavity. The large photoluminescence enhancement factor (PLEF) is attributed to the induced OP local electric field (E z ) within the nanocavity, which facilitates effective OP exciton− plasmon interaction and subsequent tremendous enhancement. Moreover, the nanoantenna effect resulting from the effective interaction improves the directivity of spontaneous radiation. Our results not only reveal an effective photoluminescence enhancement approach for OP excitons but also present an avenue for designing on-chip photonic devices with an OP dipole orientation.

Twisted van der Waals Quantum Materials: Fundamentals, Tunability, and Applications

“…Typically, increasing the excitation power can lead to a higher emission intensity of excitons, but this approach also raises the possibility of helping the localized excitons to escape the trapping caused by moiré potentials. Thus, the optimization of the emission rate in the moiré system has to be considered through incorporation with some external means, such as reducing the dielectric effect by adjusting the surrounding environment or integrating with plasmonic or metasurface microcavities. Furthermore, moiré optoelectronics holds great promise for on-chip applications, such as the development of good-performance moiré lasers, programmable quantum light sources and quantum simulations of the Bose–Hubbard model.…”

Giant optical absorption of a PtSe2-on-silicon waveguide in mid-infrared wavelengths

“…Researchers have studied several methods to improve the light-PtSe 2 interaction, such as waveguide structures, 34,35 semiconductor-metal plasmonic structures, 36–38 and photonic cavity structures. 39,40 However, the study of the optical absorption of PtSe 2 -on-silicon waveguides in the SWMIR band has been seldom explored.…”

Fluorescence Enhancement of Crystal Violet in Low-Loss Plasmonic Nanocavity Formed by Gold Nanorod on Single-Crystalline Gold Microflake

“…Among them, nanoparticles on metal film (NPoF) nanocavities formed by a closely spaced metal nanoparticles and metal film have attracted extensive research interest in recent years. − They are easy to be manufactured with the gaps between nanoparticles and film even down to the subnanometer scale and can produce extreme optical confinement and great enhancement of electromagnetic field. NPoF nanocavities offer a remarkable and versatile plasmonic platform and demonstrate a wide variety of applications in nanophotonics, including the enhancement of optical nonlinearity, , Raman scattering spectroscopy − and spontaneous emission, − strong coupling, − ultrasensitive optical sensing, , quantum optics, , etc., and have produced a series of breakthroughs, such as “pico-cavity” single-molecule photomechanics, room-temperature single-molecule strong coupling, subpicometer-scale displacement sensing …”

“…Usually, metal films in NPoF nanocavities are gold or silver films prepared by deposition technology, ,− but they have a polycrystalline structure and/or a surface root-mean-square (RMS) roughness of up to several nanometers. For light fields confined into nanoscale gaps, scattering of electrons by rough metal surfaces and numerous grain boundaries can introduce significant optical losses, thereby reducing the optical quality of NPoF nanocavities. − Single-crystalline gold microflakes (GMFs) are an alternative to polycrystalline rough metal films in NPoF nanocavities.…”