Feshbach resonances and their interaction in light scattering off photonic crystal slabs

TL;DR

This paper applies the concept of Feshbach resonances from quantum mechanics to classical light scattering in photonic crystal slabs, analyzing their formation, interaction, and effects on reflectivity and field enhancement.

Contribution

It demonstrates the realization of Feshbach resonances in photonic structures and investigates their interaction and influence on optical properties using a simple resonance dominance approximation.

Findings

Identification of parameters controlling resonance shape and field enhancement.

Analysis of interaction effects between overlapping resonances.

Differences in TE and TM resonance properties.

Abstract

The concept of Feshbach resonances developed for quantum mechanical scattering is applied in the analysis of classical light scattering off photonic crystal slabs. It is shown that this concept can be realized almost perfectly in these systems. As an application guided-mode resonances in the grating waveguide structure (GWS) are studied in detail. Using simple resonance dominance approximation the characteristic properties of isolated Feshbach resonances in light scattering are exhibited. Formation and interaction of overlapping resonances are investigated. The relevant parameters of the GWS are identified which control the shape of the reflectivity of interacting resonances as well as the enhancement of the electromagnetic field. The differences in the properties of TE and TM resonances is emphasized for both isolated and interacting resonances.