The development of pixelated dielectric metasurfaces, with individual pixels that are engineered to have distinct narrow-band reflectance resonances in the mid-infrared, is bringing new opportunities for low-cost spectrometry and molecule identification. Andreas Tittl and co-workers from the École Polytechnique Fédérale de Lausanne in Switzerland and the Australian National University in Canberra, fabricated up to 10 × 10 arrays of metasurface pixels. Each pixel was 100 × 100 μm2 and composed of a series of tiny elliptical amorphous silicon resonators (pictured). The entire array thus hosted a family of tightly packed narrow-band reflections covering the 1,350 to 1,750 cm–1 spectral region. With a thin layer of protein deposited on the surface of pixels and illuminated with mid-infrared light, a molecular absorption signature or ‘molecular barcode’ of the sample can be imaged by a detector, allowing the constituents of the sample to be identified. The team successfully tested the approach with protein A/G and mixtures of polymer molecules and say that it may aid biosensing and environmental monitoring.