Planar Super-Oscillation Diffractive Lenses: Practical Developments and Applications

As a type of inverse-designed micro/nanophotonic device, planar super-oscillation diffractive lenses (PSODLs) require complex trade-offs among multiple key performance metrics to optimize their performance, including spot size, focusing efficiency, field of view (FOV), depth of focus (DOF), and working bandwidth. This review focuses on two representative types of PSODLs, super-oscillatory lenses (SOLs) and supercritical lenses (SCLs). Both can generate far-field focal spots with sizes below the diffraction limit, but they exhibit distinct optical-field focusing characteristics, and there are trade-offs among performance parameters. Therefore, this review provides specific guidance for the selection and optimization of PSODLs in accordance with application scenarios. To better promote the practical application of these kinds of lenses, a systematic analysis of typical applications in areas such as super-resolution imaging, micro/nanofabrication, and high-precision measurement is provided. Potential extensions of PSODLs to integrated optical imaging systems, optical sensing, particle manipulation, and optical storage are also discussed. Future practical deployment of PSODLs will rely on application-oriented multiobjective optimization, robust and scalable fabrication, active system integration, and standardized performance evaluation.