Meta-Imaging: from Non-Computational to Computational

Imaging equipment is one of the most powerful tools for the human to explore the world. Devices utilizing various portions of the electromagnetic spectrum are developed to reveal the fine details of objects and extend the sensing range. Recently, the advent of metamaterials/metasurfaces has significantly advanced the evolution of both imaging components and techniques. Many promising imaging methods based on metamaterials/metasurfaces arise owing to their superior spatial modulation capabilities over the electromagnetic waves. This review focuses on applications of metamaterials/metasurfaces in the electromagnetic/optical imaging, and summarizes the recent developments of metamaterial/metasurface imaging in a new perspective, which can be categorized into the non-computational and the computational ones. First, the purposes, principles, methodology of non-computational meta-imaging are presented, which covers the evanescent-wave-collecting lens with sub-diffraction-limited imaging potentials and the focal metalens with Fourier transformation functionalities. Second, the principles of various computational meta-imaging methodologies are elucidated, including mainly the Born approximation, the synthetic aperture radar, and the ghost imaging. Finally, a brief conclusion and prospects to meta-imaging will be provided.