Mid-wave infrared multispectral imaging with HgCdTe photodetector

Multispectral imaging, which combines spatial and spectral resolution, enables accurate identification of materials and structures based on their characteristic absorption or reflection spectra, particularly in the infrared range. Despite its broad application potential, the development of multispectral imaging systems in the mid-wave infrared region remains limited. Here, we report a two-step lithography fabrication strategy for precise implementing of a pixel-level bandpass filter array, comprising four mid-infrared filters arranged in a 2 × 2 pattern, onto 640 × 512 HgCdTe photodetectors with an ultrafine 15 µm pitch. This approach enables simultaneous acquisition of multiple mid-wave infrared spectral bands within a single fabricated device, achieving excellent performance with a noise equivalent temperature difference below 25 mK. The reconstructed images effectively differentiate complex structural components within a scene and resolve fine details of the imaging targets. This work establishes an effective and scalable route for the practical realization of high-performance multispectral photodetectors, advancing the capabilities of mid-infrared imaging technologies.