Fano resonances at light scattering by an obstacle

TL;DR

This paper demonstrates that light scattering by obstacles exhibits Fano resonances, analogous to quantum systems, with localized plasmons playing the role of quasi-discrete levels and radiative decay akin to tunneling.

Contribution

It establishes a theoretical analogy between elastic light scattering and quantum scattering, introducing models that illustrate Fano resonances in optical systems.

Findings

Fano resonances occur in light scattering by obstacles.

Localized plasmons act as quasi-discrete levels.

Radiative decay mimics quantum tunneling effects.

Abstract

It is shown that elastic resonance scattering of light by a finite-size obstacle with weak dissipation is analogous to quantum scattering by a potential with quasi-discrete levels and exhibits Fano resonances. Localized plasmons (polaritons), exited in the obstacle by the incident light, are equivalent to the quasi-discrete levels, while the radiative decay of these excitations plays exactly the same role as tunnelling from the quasi-discrete levels for the quantum problem. Mie scattering of light by a spherical particle and an exactly solvable discrete model with nonlocal coupling simulating wave scattering in systems with reduced spatial dimensionality are discussed as examples.