Synthesizing quasi-bound states in the continuum in epsilon-near-zero layered materials

TL;DR

This paper presents a systematic method to create high-quality quasi-bound states in the continuum within epsilon-near-zero layered materials, enabling advanced nanophotonic applications like sensing and light trapping.

Contribution

It introduces a novel procedure for synthesizing quasi-BIC resonances in layered epsilon-near-zero materials, including phenomenological insights and effects of material loss.

Findings

Successful synthesis of sharp quasi-BIC resonances

Resonances applicable to both TE and TM polarizations

Potential applications in nanophotonics such as sensing and light trapping

Abstract

Bound states in the continuum (BIC) are highly confined, nonradiative modes that can exist in open structures, despite their potential compatibility and coupling with the radiation spectrum, and may give rise to resonances with arbitrarily large lifetimes. Here, we study this phenomenon in layered materials featuring epsilon-near-zero constituents. Specifically, we outline a systematic procedure to synthesize quasi-BIC resonances at given frequency, incidence angle and polarization, and investigate the role of certain critical parameters in establishing the quality factor of the resonances. Moreover, we also provide an insightful phenomenological interpretation in terms of the recently introduced concept of "photonic doping", and study the effects of the unavoidable material loss and dispersion. Our results indicate the possibility to synthesize sharp resonances, for both transversely magnetic and electric polarizations, which are of potential interest for a variety of nanophotonics scenarios, including light trapping, optical sensing and thermal radiation.