Purcell factors and Forster resonance energy transfer in proximity to helical structures

TL;DR

This paper investigates how helical structures can significantly enhance spontaneous emission and energy transfer rates, revealing oscillatory behavior linked to the helix pitch, with potential applications in biological and nanophotonic systems.

Contribution

It introduces an eigenpermittivity formalism to analyze emission and FRET near anisotropic helical structures, demonstrating large Purcell factors and long-range energy transfer effects.

Findings

Large Purcell factors near helical structures

Long-range FRET oscillating with helix pitch

Modes associated with strong, delocalized response

Abstract

Both spontaneous emission and resonant energy transfer can be enhanced significantly when the emitter is placed in the vicinity of metallic or crystal structures. This enhancement can be described using the electromagnetic Green tensor and is determined by the dominant surface modes of the structure. Here we use the eigenpermittivity formalism to derive the spontaneous emission and FRET rates in the quasistatic regime in a two-constituent medium with an anisotropic inclusion. We then apply our results to a helical structure supporting synchronous vibrations and evaluate the contribution of these modes, which are associated with a strong and delocalized response. We show that this contribution can result in large Purcell factors and long-range FRET, which oscillates with the helix pitch. These findings may have implications in understanding and controlling the interactions of molecules close to helical structures such as the microtubules.