Wide field-of-view metalens array for the long-wavelength infrared

Wide field-of-view (FOV) optical functionality is crucial for implementation of long wavelength infrared (LWIR) imaging device. Traditionally, wide-angle LWIR imaging requires complex assembly of multiple optical components, which increases the weight and complexity of LWIR imaging system. Here, we propose a metalens array based on all-silicon for wide-angle imaging at 10μm wavelength. To reduce coma induced by the focusing of wide-angle incident light, the phase distribution of each metalens is carefully designed by intentionally introduced shifted phase terms. After stitching the images of each metalens into a complete wide-angle image, wide-angle LWIR imaging of >60° can be achieved. We fabricate the metalens array and experimentally demonstrate focusing and imaging over the entire FOV. Our device is essential for the miniaturization of LWIR imaging system, laying the technical foundation for the development of the next generation high-performance infrared imaging systems.