Universal lineshapes at the crossover between weak and strong critical coupling in Fano-resonant coupled oscillators

TL;DR

This paper presents a comprehensive model for Fano-resonant coupled oscillators that unifies weak and strong coupling regimes, providing analytical tools to understand lineshapes and absorption for diverse applications.

Contribution

The authors develop a general analytical model that captures the transition between weak and strong critical coupling in Fano-resonant systems, including asymmetry effects.

Findings

Model describes lineshapes across coupling regimes

Analytical formulas aid device design and interpretation

Applicable to nanophotonics, plasmonics, and optomechanics

Abstract

In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators. The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed. Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.