Pixelated BIC metasurfaces for terahertz integrated sensing and imaging

Conventional terahertz (THz) single-pixel imaging relies on a sequential process involving compressed sensing, which requires a spatial modulator and is often time-intensive. Here, we propose a new THz single-pixel imaging scheme operating in a parallelized fashion with a pixelated metasurface, demonstrated within a standard THz time-domain spectroscopy system. This approach encodes spatial information through multiple narrow linewidth resonances based on bound states in the continuum (BIC) physics, and the BIC-enabled pixelated metasurface facilitates the near-field distributed sensing through local field enhancement. We validate this integrated imaging and sensing capability using a 2×2 metasurface array in a proof-of-concept experiment, with scalability to larger arrays. The approach achieves 100% accuracy in binary imaging reconstruction from a single THz pulse and enables refractive index sensing with a sensitivity higher than 14.39 GHz/RIU. Leveraging the intrinsic penetration capability of THz radiation, this technique offers significant promise for next-generation noninvasive applications such as security inspection and defect detection in semiconductor chips and pharmaceutical products.