Ultrasensitive hyperspectral imaging and biodetection enabled by dielectric metasurfaces

Metasurfaces based on resonant subwavelength photonic structures enable novel ways of wavefront control and light focusing, underpinning a new generation of flat-optics devices1. Recently emerged all-dielectric asymmetric metasurfaces, composed of arrays of metaunits with broken in-plane inversion symmetry2–7, exhibit high-quality resonances originating from the intriguing physics of bound states in the continuum. Here, we combine dielectric metasurfaces and hyperspectral imaging to develop an ultrasensitive label-free analytical platform for biosensing. Our technique can acquire spatially resolved spectra from millions of image pixels and use smart data-processing tools to extract high-throughput digital sensing information at the unprecedented level of less than three molecules per μm2. We further show spectral data retrieval from a single image without using spectrometers, enabled by our unique sensor design, paving the way for portable diagnostic applications. This combination of nanophotonics and imaging optics extends the capabilities of dielectric metasurfaces to analyse biological entities and atomic-layer-thick two-dimensional materials over large areas. Spatially resolved spectra from millions of pixels and information extraction from three molecules per μm2 is now possible using dielectric metasurfaces.