Inverse Design of\nAberration-Corrected Hybrid Metalenses\nfor Large Field of View Thermal Imaging Across the Entire Longwave\nInfrared Atmospheric Window

Long wave infrared (LWIR) cameras play a pivotal role\nacross diverse\napplications due to their distinctive features. The growing demand\nfor high-performance thermal imaging optics, characterized by a broad\nworking bandwidth, large field of view (FOV), aberration-free design,\nlightweight construction, compactness, and cost-effectiveness, poses\nsignificant challenges for LWIR lens design. Here, we propose an inverse\ndesign method for LWIR hybrid metalenses, specifically aiming to achieve\naberration-corrected thermal imaging with both a large FOV and a broad\nworking bandwidth. Our approach involves optimizing phase profiles\nof metalens’ unit cells guided by a loss function that compares\nthe hybrid lens design to diffraction-limited results for various\nincident angles and wavelengths. As a result, we demonstrate an aberration-corrected\nthermal camera with a 30° FOV and an achromatic working bandwidth\nspanning the entire LWIR atmospheric window (8 to 14 μm). Significantly,\nthe total optical path length, the entrance pupil to the sensor plane\nof the charge-coupled device (CCD), is a mere 13.6 mm. Our work merits\nadvantages in the FOV, working bandwidth, and compactness, which surpass\nstate-of-the-art LWIR hybrid metalens designs and find numerous imaging\nand sensing applications.