Abstract Bound states in the continuum (BIC) leverage symmetry-protected resonant modes for exceptional light confinement, yet their leaky modes are almost underutilized. Meanwhile, multiple quantum well (MQW) structures face limited optical absorption due to strict transition selection rules. We demonstrate the regulation of the leaky mode of quasi-BIC (QBIC) by analyzing MQW-vertical field coupling, revealing that increasing asymmetric parameters enhances the transverse leakage of wave vector and optical field nonlinearly. This drives a nonlinear photoresponse as increasing asymmetry parameter, while linear scenario with incident angle and external bias voltage. We then develop an optoelectrical fusion neuromorphic processor, implementing QBIC-MQWs into an artificial neural network for machine vision applications. Similar content being viewed by others Introduction Metasurfaces enable subwavelength-pixelated light manipulation of amplitude, phase, polarization, and propagation, emerging as a transformative platform for tailoring light-matter interactions. This capability facilitates in-situ electromagnetic wave engineering in integrated optoelectronic systems, unlocking monolithic designs for advanced photonic processors1,2,3,4. Bound states in the continuum (BIC) that exploit nonradiating modes to achieve theoretically infinite quality factors (Q) and their quasi-BIC (QBIC) counterparts that emerge via symmetry-broken perturbations to enable high-Q leaky resonances, accompanied with unprecedented light confinement in subwavelength volumes, have received significant attention in nanoscale lasing5,6,7,8,9,10,11, biomolecular sensing12,13,14, optical imaging15, and other meta-devices16,17,18,19,20,21,22,23,24,25,26,27,28. These works primarily focus on the resonance modes arising from electromagnetic interference within periodic meta-atom arrays. The exploration and application of the symmetry-broken leaky modes generated by engineered radiation channels of QBIC remain relatively limited. According to Bloch theorem, electromagnetic modes can be represented by a wave vector k|| = (kx, ky) that is parallel to the xy plane. For symmetry-protected BICs, the radiation direction is purely normal to the xy plane, yielding k||≈0. Nevertheless, once the symmetry is broken, a structural perturbation that breaks the symmetry can transform a BIC into a