Optical characterization of size- and substrate-dependent performance of ultraviolet hybrid plasmonic nanowire lasers

TL;DR

This study systematically investigates how substrate material and nanowire size influence the lasing performance of ZnO nanowire-based plasmonic lasers, revealing the role of exciton-plasmon coupling in device efficiency.

Contribution

It introduces a hybrid nanomanipulation and high-throughput spectroscopy method to correlate nanowire size and substrate effects on lasing characteristics.

Findings

Substrate material significantly affects lasing thresholds.

Nanowire diameter influences exciton-plasmon coupling.

Lasing character varies between plasmonic and photonic regimes.

Abstract

Nanowire-based plasmonic lasers are now established as nano-sources of coherent radiation, appearing as suitable candidates for integration into next-generation nanophotonic circuitry. However, compared to their photonic counterparts, their relatively high losses and large lasing thresholds still pose a burdening constraint on their scalability. In this study, the lasing characteristics of ZnO nanowires on Ag and Al substrates, operating as optically-pumped short-wavelength plasmonic nanolasers, are systematically investigated in combination with the size-dependent performance of the hybrid cavity. A hybrid nanomanipulation-assisted single nanowire optical characterization combined with high-throughput PL spectroscopy enables the correlation of the lasing characteristics to the metal substrate and the nanowire diameter. The results evidence that the coupling between excitons and surface plasmons is closely tied to the relationship between substrate dispersive behavior and nanowire diameter. Such coupling dictates the degree to which the lasing character, be it more plasmonic- or photonic-like, can define the stimulated emission features and, as a result, the device performance.