Electrically Tunable and Robust Bound States in the Continuum Enabled by 2D Transition Metal Dichalcogenide

摘要

High quality factor (Q-factor) resonance can effectively enhance light–matterinteractions, but suffers from radiative losses caused by fabrication imperfectionsand material impurities. Merging bound states in the continuum(BICs) becomes a promising candidate to address this challenge since theygenerate a large high-Q region in momentum space against undesiredexternal perturbations. However, it is only achieved by altering the geometricparameters of the structure, which constrains its dynamical tunability oncethe fabrication is ready, limiting its performance in modulators and photodetectors.Here, a convenient approach is proposed to manipulating themerging BIC by electrically tuning the material properties, aiming at on-chipphotonic devices. The asymmetric merging BIC is achieved and tuned byreducing the in-plane structural symmetry from C_4~Z to C_2~Z , which enablesthe inversion of topological charge and reconfigurable polarization distributionin the momentum space. Such tunable merging BIC promises variouspotential applications including vortex generation, optical communication,and nanolasers.