High momentum two-dimensional propagation of emitted photoluminescence coupled with surface lattice resonance

Abstract

Dramatic fluorescence enhancement in two-dimensional (2D) van der Waals materials (vdWMs) coupled to plasmonic nanostructures has the potential to enable ultrathin, flexible, and high-brightness illumination devices. However, addressing the limitation of locally scattered small plasmon-enhanced areas remains challenging. Here, we present a 2D plasmonic enhancement of photoluminescence (PL) spanning nearly 800 μm², enabled by surface lattice resonance (SLR) in a 2D vdWM-Au slot lattice hybrid. The Au slot lattice is designed and fabricated using Babinet’s principle and Rayleigh’s anomaly to maximize radiative decay rate and induce non-local photo-excitation in a MoSe₂ monolayer. For emitted PL coupled with SLR, enhanced by up to 32-fold, we investigate its in-plane directivity and long-range propagation using angle- and space-resolved spectroscopic PL measurements. Our experiment reveals that a nearly 800 μm² 2D luminescent sheet can be achieved regardless of the size of the MoSe₂ crystal, even with a sub-μm² flake. This work provides a new type of ultrabright, large-area 2D luminescent material, suitable for a range of optical illumination, communication, and sensing devices.