Observation of multi-orbital Fano resonances in photonic lattices

Abstract

Fano resonances are a fundamental physical phenomenon that occurs when an open channel couples with a closed one, resulting in a resonant cancellation of transmission. In this article, we introduce a quantum simulator designed to observe multi-orbital Fano resonances using a photonic waveguide analog. The system consists of a homogeneous lattice, which includes a plane wave generator, and an atom-like impurity that supports first-order (S) and second-order (P) modes. We derive a two-impurity Fano-Anderson model to describe this system and fit the experimental results accordingly, demonstrating a remarkable agreement between our experimental measurements and theoretical predictions. A comprehensive experimental characterization reveals clear double resonances for the S and P states, which depend on the properties of the atom and the excitation wavelength. Our results illustrate how the transport of a propagating beam on a lattice can be effectively controlled by simply adjusting the properties of a single external atom-like impurity, which works as an efficient energy valve.