Resonance Wavelength Stabilization of Quasi-Bound States in the Continuum Constructed by Symmetry Breaking and Area Compensation.

Dielectric metasurface supported symmetry-protected bound states in the continuum (SP-BIC) provide an important platform for enhancing light-matter interactions. However, the conversion of SP-BIC into quasi-BIC (QBICs) through symmetry breaking is often accompanied by a shift in the resonance wavelength. In this work, we present a generalized viewpoint aimed at achieving the wavelength stability of QBICs through symmetry breaking and area compensation (SBAC). Three SBAC schemes we propose are equal proportional compensation along both x- and y-directions and equal proportional compensation along x-direction only or y-direction only. The QBICs resonance wavelengths stabilized at about 1200, 1520, and 1434 nm are achieved in monomer, dimer, and tetramer metasurfaces, respectively. Finally, we perform an experimental demonstration in a nanohole dimer photonic crystal slab. The QBICs resonance wavelength stabilized at 1658 nm for SBAC. Our approach provides new routes for realizing QBICs with a stable wavelength and tunable Q-factor.