Electrically Reconfigurable Quasi‐BIC Metadevices Enabled by Integrated Barium Titanate

ABSTRACT 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 BaTiO 3 ) 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 μm 2 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.