Dissipative Coupling in Photonic and Plasmonic Resonators

TL;DR

This paper introduces a coupled-quasinormal-mode framework for analyzing dissipative coupling in photonic and plasmonic resonators, enabling accurate predictions of complex phenomena beyond traditional models.

Contribution

It provides a rigorous, closed-form analytical approach for dissipative coupling, including novel features like coupling via time derivatives, surpassing classical coupled-mode theory.

Findings

Accurately predicts zero-coupling between close cavities.

Captures level-attraction effects not explained by traditional models.

Offers a practical framework for device design and future extensions.

Abstract

The rapid progress of nanophotonics demands theoretical frameworks capable of predicting the resonant behavior of complex systems comprising constituents of varying nature, operating beyond the weak-coupling, high-Q regime where classical temporal coupled-mode theory (CMT) is applicable. This work presents a coupled-quasinormal-mode (cQNM) framework for analyzing dissipative coupling with photonic and plasmonic resonators. The framework provides rigorous closed-form expressions for dissipative coupling coefficients and introduces novel features, such as a new coupling scheme via time derivatives of excitation coefficients. It delivers transparent and accurate predictions of exotic phenomena-such as zero-coupling between very close cavities and level-attraction effects that are only vaguely captured by traditional CMT models. Efficient and user-friendly, this framework facilitates rapid parameter space exploration for device design and offers potential for extension to nonlinear and quantum systems in future applications.