Fano resonances in scattering: an alternative perspective

TL;DR

This paper demonstrates that Fano resonances in scattering, especially near exceptional points, can be accurately described by the Beutler-Fano formula, providing a new perspective on asymmetric line profiles.

Contribution

It offers an alternative interpretation of Fano resonances in scattering through the Green's function pole interference and introduces energy-dependent Fano parameters for better accuracy.

Findings

Fano line profiles are well described by the Beutler-Fano formula.

Interference of Green's function poles explains asymmetric scattering profiles.

Energy-dependent Fano parameters improve the description away from exceptional points.

Abstract

In a previous paper it has been shown that the interference of the first and second order pole of the Green's function at an exceptional point, as well as the interference of the first order poles in the vicinity of the exceptional point, gives rise to asymmetric scattering cross section profiles. In the present paper we demonstrate that these line profiles are indeed well described by the Beutler-Fano formula, and thus are genuine Fano resonances. Also further away from the exceptional points excellent agreement can be found by introducing energy dependent Fano parameters.