Broadband generation of quasi bound-state-in-continuum modes using subwavelength truncated cone resonators

TL;DR

This paper demonstrates a method to generate broadband quasi-bound states in the continuum using truncated nano-cone resonators, enabling high Q-factors over a wide wavelength range for practical applications.

Contribution

Introducing a structural design using base angle as a degree of freedom to achieve broadband Q-BIC resonances in subwavelength dielectric resonators.

Findings

Achieved Q-factor >150 over >100 nm wavelength range

Supported broadband Q-BIC resonance with truncated nano-cone resonators

Enhanced practical applicability of Q-BIC for spectral tuning

Abstract

Allowing a high quality factor (Q-factor) to a sub-wavelength dielectric resonator, quasi-bound states in the continuum (Q-BIC) has gained much interest. However, the Q-BIC resonance condition is too sensitive to the geometry of the resonator and its practical broadband generation on a single-wafer platform has been limited. Here, we present that employing the base angle as a structural degree of freedom, the truncated nano-cone resonator supports the Q-BIC resonance with a high Q-factor of >150 over a wide wavelength range of >100 nm. We expect our approach will boost the utilization of the Q-BIC resonance for various applications requiring broadband spectral tuning.