Distance-dependent interaction between a single emitter and a single dielectric nanoparticle using DNA origami

Abstract

Optical nanoantennas can manipulate light-matter interactions at the nanoscale, modifying the emission properties of nearby single photon emitters. To date, most optical antennas are based on metallic nanostructures that exhibit unmatched performance in terms of electric field enhancement but suffer from substantial ohmic losses that limit their applications. To circumvent these limitations, there is a growing interest in alternative materials. In particular, high-refractive-index dielectrics have emerged as promising candidates, offering negligible ohmic losses, and supporting both electric and magnetic resonances in the visible and near-infrared range that can unlock novel effects. Currently, the few available studies on dielectric nanoantennas focus on ensemble measurements. Here, the DNA origami technique is exploited to study the interaction between silicon nanoparticles and organic fluorophores at the single-molecule level, in controlled geometries and at different spectral ranges within the visible spectrum. Their distance-dependent interaction is characterized in terms of fluorescence intensity and lifetime, revealing a significant modification of the decay rate together with minimal quenching and a high-fluorescence quantum yield even at short distances from the dielectric nanoparticle. This work demonstrates the advantages of dielectric nanoantennas over their metallic counterparts and paves the way for their applications in single-molecule spectroscopy and sensing.