Theory for polariton-assisted remote energy transfer

TL;DR

This paper develops a comprehensive theory for polariton-assisted remote energy transfer (PARET), revealing mechanisms and conditions under which strong light-matter coupling enables long-range molecular energy transfer up to a micron.

Contribution

It introduces the first detailed theoretical framework for PARET involving surface plasmons and vibrational relaxation, highlighting how coherence and coupling regimes influence transfer.

Findings

PARET up to a micron is achievable via strong-coupling.

Two regimes of PARET: plasmon-mediated and vibrational relaxation-mediated.

Strong-coupling to acceptors can enable energy transfer from acceptors to donors.

Abstract

Strong-coupling between light and matter produces hybridized states (polaritons) whose delocalization and electromagnetic character allow for novel modifications in spectroscopy and chemical reactivity of molecular systems. Recent experiments have demonstrated remarkable distance-independent long-range energy transfer between molecules strongly coupled to optical microcavity modes. To shed light on the mechanism of this phenomenon, we present the first comprehensive theory of polariton-assisted remote energy transfer (PARET) based on strong-coupling of donor and/or acceptor chromophores to surface plasmons. Application of our theory demonstrates that PARET up to a micron is indeed possible via strong-coupling. In particular, we report two regimes for PARET: in one case, strong-coupling to a single type of chromophore leads to transfer mediated largely by surface plasmons while in the other case, strong-coupling to both types of chromophores creates energy transfer pathways mediated by vibrational relaxation. Importantly, we highlight conditions under which coherence enhances or deteriorates these processes. For instance, while exclusive strong-coupling to donors can enhance transfer to acceptors, the reverse turns out not to be true. However, strong-coupling to acceptors can shift energy levels in a way that transfer from acceptors to donors can occur, thus yielding a chromophore role-reversal or "carnival effect." This theoretical study demonstrates the potential for confined electromagnetic fields to control and mediate PARET, thus opening doors to the design of remote mesoscale interactions between molecular systems.