Lasing in an Assembled Array of Silver Nanocubes

TL;DR

This paper demonstrates a plasmonic nanolaser using assembled silver nanocube arrays with surface lattice resonance, achieving low threshold and high beam quality, suitable for scalable applications.

Contribution

It introduces a method for assembling high-quality colloidal silver nanocubes into arrays that support lasing via surface lattice resonance, even without perfect array arrangements.

Findings

Lasing at 574 nm with <1.2 nm linewidth

Lasing threshold below 100 μJ/cm²

Beam divergence less than 1 mrad

Abstract

We demonstrate a surface lattice resonance (SLR)-based plasmonic nanolaser that leverages bulk production of colloidal nanoparticles and assembly on templates with single particle resolution. SLRs emerge from the hybridization of the plasmonic and photonic modes when nanoparticles are arranged into periodic arrays and this can provide feedback for stimulated emission. It has been shown that perfect arrays are not a strict prerequisite for producing lasing. Here, we propose using high-quality colloids instead. Silver colloidal nanocubes feature excellent plasmonic properties due to their single-crystal nature and low facet roughness. We use capillarity-assisted nanoparticle assembly to produce substrates featuring SLR and comprising single nanocubes. Combined with the laser dye pyrromethene-597, the nanocube array lases at 574 nm with <1.2 nm linewidth, <100 uJ/cm2 lasing threshold, and produces a beam with <1 mrad divergence, despite less-than-perfect arrangement. Such plasmonic nanolasers can be produced on a large-scale and integrated in point-of-care diagnostics, photonic integrated circuits, and optical communications applications.