Search

Distinct from conventional optical lenses suffering from the diffraction limit, the superoscillatory lens offers an alternative approach to realize far‐field sub‐diffraction focusing and find significant applications in both microscopy and telescopy. During the past few years, planar micro/nanostructures are unitized to precisely manipulate the optical fields through a standard lens to realize a superoscillatory field along the radial direction of the pupil. Here, an angular superoscillatory metalens (ASOM) is demonstrated by combining the superoscillatory phase and angular metalens phase in a single metasurface. To the best of the authors' knowledge, this is the first work that focuses on the angular superoscillatory phenomenon. As a proof‐of‐concept application demo, this study shows the ASOM can map the received orbital angular modes (OAMs) into focusing patterns at the focal plane with different azimuth angles. Therefore, the OAM spectrum incorporating multiple modes can be determined with a single‐shot measurement according to the precalibrated mapping relationship. This study shows that the OAM resolution is scaled up about 3.2 times compared with a normal angular metalens, thanks to the shrinkage of the focal patterns. This approach may push the development of integrated and high‐dimensional optical and quantum systems. [ABSTRACT FROM AUTHOR]

Light beam carrying spin angular momentum (SAM) and orbital angular momentum (OAM) have attracted great interest due to their great potential for high‐capacity optical communication, optical tweezers, and quantum information. However, the current detection methods suffer from the lack of robustness to misalignments in the optical system, which limits the detection accuracy and the application for off‐axis vortex array detection. Here, a high‐efficiency, broadband, and single‐layer metasurface design is proposed for alignment‐free angular momentum detection via spin‐independent astigmatic transformation (SIAT). The SAM and OAM states can be recognized from the diffraction direction and patterns, respectively. Proof‐of‐concept demonstrations are experimentally carried out on different incident beams including circular‐polarization, linear‐polarization, and vector vortex beams, as well as vortex beam arrays, showing a high diffraction efficiency of ≈81% at 1064 nm while operating within the broadband region of 900–1300 nm. The alignment‐free merit for the incident position, incident angle, and detector distance grants the device great potential for integrated quantum systems and multiparticle micromanipulation with optical tweezers. [ABSTRACT FROM AUTHOR]

The article titled "Angular Superoscillatory Metalens Empowers Single-Shot Measurement of OAM Modes with Finer Intervals" introduces the concept of an angular super-oscillatory metalens (ASOM) that combines superoscillatory phenomena with an angular metalens. This ASOM allows for sub-diffractive focusing of vortex beams along the angular direction, enabling the determination of large-capacity orbital angular modes with a single snapshot measurement. Compared to traditional angular metalenses, the ASOM improves the sorting resolution by more than three times, which has potential applications in high-dimensional optical and quantum systems. The article provides further details on this topic. [Extracted from the article]