Environmental permittivity-asymmetric BIC metasurfaces with electrical reconfigurability

TL;DR

This paper presents a novel approach to creating reconfigurable bound states in the continuum (BICs) by environmental permittivity asymmetry, enabling active tuning without altering resonator geometry, demonstrated with electro-optic polymer integration.

Contribution

It introduces environmental symmetry breaking via refractive index contrast for permittivity-driven quasi-BICs, bypassing geometric symmetry breaking limitations and enabling electrical reconfigurability.

Findings

Demonstrated electrically reconfigurable qBICs using PANI polymer.

Achieved rapid switching speeds and high durability.

Enhanced optical response to environmental changes.

Abstract

In the rapidly evolving field of nanophotonics, achieving precise spectral and temporal light manipulation at the nanoscale remains a critical challenge. While photonic bound states in the continuum (BICs) have emerged as a powerful means of controlling light, their common reliance on geometrical symmetry breaking for obtaining tailored resonances makes them highly susceptible to fabrication imperfections and fundamentally limits their maximum resonance quality factor. Here, we introduce the concept of environmental symmetry breaking by embedding identical resonators into a surrounding medium with carefully placed regions of contrasting refractive indexes, activating permittivity-driven quasi-BIC resonances without any alterations of the underlying resonator geometry and unlocking an additional degree of freedom for light manipulation through actively tuning the surrounding refractive index contrast. We demonstrate this concept by integrating polyaniline (PANI), an electro-optically active polymer, to achieve electrically reconfigurable qBICs. This integration not only demonstrates rapid switching speeds, and exceptional durability but also significantly boosts the system's optical response to environmental perturbations. Our strategy significantly expands the capabilities of resonant light manipulation through permittivity modulation, opening avenues for on-chip optical devices, advanced sensing, and beyond.