High-resolution spectral imaging with quasi bound states in the continuum

Computational spectral imaging is an emerging interdisciplinary technique with extensive applications. Current systems based on meta-surfaces use broad-band nanophotonic encoders for spectral encoding, which requires a high sampling rate to achieve ideal spectral resolution. In this study, we propose a high-resolution computational spectral imaging system based on quasi-bound states in the continuum (quasi-BIC) achieved by breaking the C2 symmetry of a metarectangle structure. Compared to broad-band nanophotonic encoders, quasi-BIC features a high-quality factor (Q-factor), with resonance peaks that can be shifted across a wide wavelength range by adjusting a scale factor S, and the width of these peaks can be controlled by rotating orientation angles. This quasi-BIC spectral encoder enhances the accuracy of computational reconstruction and improves spectral resolution, achieving an average peak-signal-to-noise ratio (PSNR) of 35.12 dB and an average spectral angle mapper (SAM) of 0.0616 at a sampling rate of 29%. This advancement paves the way for the development of compact and high-resolution spectral imaging devices.