Tunable dynamic Fano resonances in coupled-resonant optical waveguide

TL;DR

This paper proposes a theoretical method to dynamically control Fano resonances in coupled-resonator optical waveguides through refractive index modulation, enabling tunable lineshape engineering and potential applications in photonics.

Contribution

It introduces a Floquet-based analysis for dynamic Fano resonance control in microcavities, demonstrating tunability and the emergence of electromagnetically-induced transparency effects.

Findings

Single Fano resonance tunable in frequency and width

Two resonances can overlap to produce transparency

Exact Floquet analysis confirms dynamic control capabilities

Abstract

A route toward lineshape engineering of Fano resonances in photonic structures is theoretically proposed, which uses dynamic modulation of the refractive index of a microcavity. The method is exemplified by considering coupled-resonator optical waveguide systems. An exact Floquet analysis, based on coupled-mode theory, is presented. Two distinct kinds of resonances can be dynamically created, depending on whether the static structure sustains a localized mode or not. In the former case a single Fano resonance arises, which can be tuned in both frequency and line width by varying the refractive index modulation amplitude and frequency. In the latter case two resonances, in the form of narrow asymmetric dips in the transmittance, are found, which can overlap resulting in an electromagnetically-induced transparency effect.