Electrically Reconfigurable Quasi-BIC Metadevices Enabled by Integrated Barium Titanate

Quasi-bound states in the continuum (quasi-BIC, Q-BIC) metasurfaces, endowed with their record high Q-factor, promise paradigm-shifts in applications of lasing, biosensing, and spectral filtering. However, their resonance is frozen, once the nanostructure is fixed, constraining real-world deployability. We report an electrically reconfigurable quasi-BIC metasurface that monolithically integrates barium titanate (BTO and BaTiO₃) electro-optic material and demonstrate its deployment as a high-performance dispersion engine platform of a chip-scale miniaturized intensity-modulator and computational reconstructive spectrometer. By concurrently hosting a symmetry-protected BIC and a guided-mode resonance, the metasurface triggers an electromagnetically induced transparency (EIT) destructive interference in the near-infrared, delivering a bandwidth of λ/2128 narrow band-stop filter. Systematic analysis of structural parameters reveals mode coupling dynamics. Leveraging the Pockels effect and mode confinement in BTO, a linear tuning slope of 1.79 nm/V is achieved. Leveraging the metasurface as a voltage-scanned tunable filter, we furtherly demonstrate a 250 μm² miniaturized spectrometer. A spectral reconstruction optimization algorithm recovers spectra with 0.2 nm resolution, 99% fidelity, and 89.47% optical throughput. These results offer a technical pathway toward miniaturized spectral engines combining sub-nanometer resolution with chip-scale portability. A scalable platform is established for active metadevices with reconfigurable Q-factor and spectral agility.