Angle-resolved miniature spectrometer using CMOS-compatible metasurface Fabry-Pérot filters and compressive sensing.

Miniaturized spectrometers based on arrayed filters on pixels are essential for portable sensing applications, but existing metasurface-based filter designs struggle with a performance penalty when the angle of illumination grows. In this work, we propose a multiplexed metasurface architecture that simultaneously reconstructs spectra and determines the angle of incidence of the dominant beam. The CMOS-compatible metasurface design combines two types of Fabry-Pérot filters: high-Q filters that maintain stable responses across angles and medium-Q filters with larger controlled angular sensitivity. Using a self-adaptive reconstruction algorithm, we exemplify accurate retrieval of chlorophyll-a fluorescence spectra with RMS error as low as 6.9 × 10-3 while determining illumination angles within 1∘ accuracy. This approach opens up practical pathways for compact spectrometers in agriculture, geological surveying, and industrial monitoring, and areas where a dominant beam is at stake, rather than a full image, with both spectral information and illumination geometry being important.