Optical Super‐Oscillation Enables Sub‐Diffraction Focusing and Super‐Resolution Imaging in the Far‐Field

Owing to the inherent wave property of light, the resolution of the optical system is constrained by the diffraction limit. Past decades have seen many efforts to break the diffraction limit at the expense of complex near‐field manipulation, pre‐labeling, or post‐processing. However, an optical access for noninvasive sub‐diffraction focusing and super‐resolution imaging in the far‐field that does not pose dependency on evanescent waves or targets is still highly desirable. Optical super‐oscillation method based on the superposition of propagating waves offers a possibility to overcome the diffraction limit in the far‐field with arbitrary enhanced resolution. This article reviews the recent progress of optical super‐oscillation technology, including research about super‐oscillation phenomenon, designs of super‐oscillatory lenses for sub‐diffraction focusing, super‐resolution imaging by optical super‐oscillation method, and applications in other domains. The shortcoming and prospective advancements of optical super‐oscillation technology are also discussed here. It is expected that this review can provide valuable insights for researchers committed to developing optical super‐oscillation technology in various fields.