225 / 2024-07-26 19:10:04

Polarization-optimized tip-enhanced strong coupling of single quantum dots

Tip-enhanced strong coupling,Tip-enhanced photoluminescence,Nanophotonics,Cavity-quantum electrodynamics,Plasmonics

Cavity quantum electrodynamics (CQED) is pivotal in manipulating light-matter interactions within quantum systems. Notably, with their nano-scale confined field, plasmonic cavities offer a pathway to achieve a strong coupling regime with various quantum emitters including atoms, quantum dots, and 2D materials. Despite its promise, plasmon-based CQED systems encounter challenges such as photon loss, precise positioning of quantum emitters within the plasmonic structure, and operational instability. Here, we propose an approach to selectively pick a single quantum dot using a gold nanotip and enable active nanocavity positioning, thereby enhancing coupling strength. We alter the excitation light polarization to reach the strong coupling regime and observe correspondingly modified photoluminescence spectra. Furthermore, our experimental results demonstrate long-term stability, with strong coupling sustained for up to 1 hour. This work opens a new avenue for the advance in photonic quantum information science.