Highly polarized light emission from hybrid of quantum dots and plasmons in the intermediate coupling regime

Colloidal semiconductor quantum dots (QDs), with a size tunable bandgap and remarkably high quantum efficiency, have been recognized as ideal light sources in quantum information and light emitting devices. For light sources, besides the emission intensity and spectral profile, the degree of polarization (DoP) is an essential parameter. Here, by embedding a monolayer of QDs inside the nanogap between a bottom Au mirror and a top Ag nanowire, we have demonstrated highly polarized light emission from the QDs with an average DoP of 0.89. In addition to the anisotropic pho-toluminescence (PL) intensity, the PL spectra are distinct at different polarizations, with an asymmetric spectral shape or even two-peak features. Such an anisotropic emission behavior arises from the coupling between the QDs and the largely confined and polarization-dependent gap-plasmons in the Au/QD/Ag nanocavities in the intermediate coupling regime. Our results demonstrate the possibility of achieving highly polarized light sources by coupling spherical QDs to single anisotropic plasmonic nanocavities, to provide new opportunities in the future design of polarized QD-based display devices. (C) 2023 Optica Publishing Group

Automated summary

In this study, highly polarized light emission from colloidal semiconductor quantum dots (QDs) was achieved by embedding a monolayer of QDs inside anisotropic plasmonic nanocavities. The average degree of polarization (DoP) was 0.89. The anisotropic emission behavior was attributed to the coupling between the QDs and the confined and polarization-dependent gap-plasmons in the nanocavities. These findings open up new opportunities for the design of polarized QD-based display devices.