Achromatic Broadband Super‐Resolution Imaging by Super‐Oscillatory Metasurface

Abstract Past decades have seen enormous efforts to achieve subdiffraction resolution optical imaging, but most of them are suffering from either complex near‐field manipulation or prelabeling of specific specimen, like scanning near‐field optical microscopes and stimulated emission depletion microscopes. The optical super‐oscillation phenomenon seems to provide a method of far field super‐resolution imaging without particularly dealing with objects. However, the reported optical super‐oscillation imaging methods were usually constrained to narrow bandwidth, which is mainly due to the inherent complex light interference features. Here, benefiting from the nearly dispersionless feature of phase modulations with metasurface, a super‐oscillatory metasurface filter is proposed for broadband super‐resolution imaging. In demonstrative experiments, resolving ability of about 0.64 times of the Rayleigh criterion is obtained for visible light ranging from 400 to 700 nm. This method is expected to potentially promote the development of super‐resolving telescopes and microscopes based on super‐oscillation optics.