Efficient DNA-driven nanocavities for approaching quasi-deterministic strong coupling to a few fluorophores

TL;DR

This paper presents a DNA-driven method to create efficient plasmonic nanocavities that enable near-deterministic strong coupling with a few fluorophores, advancing quantum photonic device integration.

Contribution

The authors develop a DNA-based assembly technique combined with lithography to precisely position fluorophore-coupled nanocavities on substrates, improving coupling efficiency and scalability.

Findings

High cavity and fluorophore coupling yields achieved.

Strong correlation observed between fluorophore transitions and cavity resonance.

Method enables practical, stable strong coupling units on microchips.

Abstract

Strong coupling between light and matter is the foundation of promising quantum photonic devices such as deterministic single photon sources, single atom lasers and photonic quantum gates, which consist of an atom and a photonic cavity. Unlike atom-based systems, a strong coupling unit based on an emitter-plasmonic nanocavity system has the potential to bring these devices to the microchip scale at ambient conditions. However, efficiently and precisely positioning a single or a few emitters into a plasmonic nanocavity is challenging. In addition, placing a strong coupling unit on a designated substrate location is a demanding task. Here, fluorophore-modified DNA strands are utilized to drive the formation of particle-on-film plasmonic nanocavities and simultaneously integrate the fluorophores into the high field region of the nanocavities. High cavity yield and fluorophore coupling yield are demonstrated. This method is then combined with e-beam lithography to position the strong coupling units on designated locations of a substrate. Furthermore, the high correlation between electronic transition of the fluorophore and the cavity resonance is observed, implying more vibrational modes may be involved. Our system makes strong coupling units more practical on the microchip scale and at ambient conditions and provides a stable platform for investigating fluorophore-plasmonic nanocavity interaction.