Optical superoscillation technologies beyond the diffraction limit

Optical superoscillations are rapid spatial variations of the intensity and phase of light. This Review describes technologies for generating superoscillatory hotspots and discuss advances in imaging and metrology with superoscillatory light that, in combination with artificial intelligence, offer deeply subwavelength optical resolution. Optical superoscillations are rapid, subwavelength spatial variations of the intensity and phase of light, occurring in complex electromagnetic fields formed by the interference of several coherent waves. The discovery of superoscillations stimulated a revision of the limits of classical electromagnetism - in particular, the studies of phenomena such as unlimitedly small energy hotspots, phase singularities, energy backflow, anomalously high wavevectors and their intriguing similarities to the evanescent plasmonic fields on metals. In recent years, the understanding of superoscillatory light has led to the development of superoscillatory lensing, imaging and metrology technologies. Dielectric, metallic and metamaterial nanostructured superoscillatory lenses have been introduced that are able to create hotspots smaller than allowed by conventional lenses. Far-field, label-free, non-intrusive deeply subwavelength super-resolution imaging and metrology techniques that exploit high light localization and rapid variation of phase in superoscillatory fields have also been developed, including new approaches based on artificial intelligence. We review the fundamental properties of superoscillatory optical fields and examine emerging technological applications.

Automated summary

Optical superoscillations involve rapid spatial variations of light intensity and phase, offering subwavelength optical resolution that can be enhanced through the use of artificial intelligence. Technologies for generating superoscillatory hotspots have been developed, enabling advancements in imaging and metrology with the potential for deeply subwavelength resolution. The understanding of superoscillatory light has led to the creation of novel superoscillatory lenses, imaging techniques, and metrology technologies that exploit high light localization and rapid phase variation, opening up new avenues for label-free, non-intrusive super-resolution imaging.