Imaging Performance of Polarization Insensitive Metalenses
Metasurfaces have recently emerged as a promising technology to realize flat optical components with customized functionalities. In particular, their application to lenses in various imaging systems is of significant interest. However, a systematic and complete study of the focusing and imaging behavior of metalenses has not yet been conducted. In this work we analyze not only the on axis focusing performance, but also the field dependent wavefront aberrations via a phase retrieval optimization method. We find that, particularly for high NA metalenses, the field dependent geometrical aberrations like coma are dominant at the design wavelength, while for longer and shorter operation wavelengths, the effective numerical aperture is decreased and mainly spherical aberrations are dominant. Additionally, we investigate the spectral and angular bandwidth of a polarization insensitive metalens by analyzing the metalens efficiencies as a function of numerical aperture, field angle, and wavelength. We then compare.
ACS Photonics