Theory of Molecular Emission Power Spectra. III. Non-Hermitian Interactions in Multichromophoric Systems Coupled with Polaritons

TL;DR

This paper extends the theory of molecular emission power spectra to multichromophoric systems in complex media, revealing how non-Hermitian interactions influence emission broadening and superradiance in polaritonic environments.

Contribution

It generalizes EPS theory to multichromophoric systems within macroscopic QED, incorporating non-Hermitian interactions and demonstrating their effects on emission spectra and superradiance.

Findings

Peak broadening depends on spontaneous emission rates and non-Hermitian dipole-dipole interactions.

Superradiance rate can be tuned by intermolecular distance and dielectric environment.

Analytical formulas describe the influence of polaritons on multichromophoric emission spectra.

Abstract

Based on our previous study [S. Wang $\textit{et al}$. J. Chem. Phys. $\textbf{153}$, 184102 (2020)], we generalize the theory of molecular emission power spectra (EPS) from one molecule to multichromophoric systems in the framework of macroscopic quantum electrodynamics. This generalized theory is applicable to ensembles of molecules, providing a comprehensive description of the molecular spontaneous emission spectrum in arbitrary inhomogeneous, dispersive, and absorbing media. In the far-field region, the analytical formula of EPS can be expressed as the product of a lineshape function (LF) and an electromagnetic environment factor (EEF). To demonstrate the polaritonic effect on multichromophoric systems, we simulate the LF and EEF for one to three molecules weakly coupled to surface plasmon polaritons above a silver surface. Our analytical expressions show that the peak broadening originates from not only the spontaneous emission rates but also the imaginary part of resonant dipole-dipole interactions (non-Hermitian interactions), which is associated with the superradiance of molecular aggregates, indicating that the superradiance rate can be controlled through an intermolecular distance and the design of dielectric environments. This study presents an alternative approach to directly analyze the hybrid-state dynamics of multichromophoric systems coupled with polaritons.