Integration of quantum dots at the tips of single plasmonic bipyramid nanoantennas for strong coupling at room temperature

TL;DR

This paper demonstrates strong room-temperature coupling between colloidal quantum dots and a single plasmonic bipyramid nanoantenna, using a novel localization technique to achieve high coupling strength and potential for quantum technology applications.

Contribution

It introduces a scalable method for precise quantum dot placement at the hotspot of a plasmonic bipyramid, enabling strong coupling at room temperature.

Findings

Achieved Rabi splitting of 349.3 meV

Demonstrated coupling strength of 175.68 meV

Confirmed anti-crossing behavior via simulations

Abstract

Achieving strong coupling between excitons of colloidal semiconductor quantum dots (QDs) and localized surface plasmon polaritons (LSPs) is critical for advanced room-temperature quantum emitter and sensing applications. A key challenge is to have precise control of the emitters position with respect to an individual plasmonic nanostructure. Here, we present room temperature strong coupling between QDs and a single gold nano-bipyramid (BPs). The selection of the bipyramid plasmonic nanocavity offers access to a single hotspot with a very small mode volume. The localization of QDs at a single hotspot is achieved via plasmon-triggered two-photon polymerization. This technique exploits the enhanced electric field at the BP tip to selectively polymerize a photosensitive QD-containing formulation. Room-temperature scattering spectra of a 3-QD-BP system reveal Rabi splitting of 349.3 meV and a coupling strength of 175.68 meV. The with distinct anti-crossing behavior is confirmed by simulations. This approach simplifies QD integration for strong coupling systems compared to previous methods. These results indicate a scalable platform for solid-state quantum technologies with colloidal QDs, enabling explora-tion of exciton-plasmon interactions and further advance-ment of applications in quantum optics and quantum sensing under ambient conditions.