Quasi-bound states in the continuum driven photoresponse in multiple quantum wells for machine vision.

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. Graphical abstract. This work presents a proof-of-concept BIC-MQW device, in which the photocurrent characteristics are leveraged to realize image processing functionalities.