Dual-layered metalens for polarization-agile orbital angular momentum waves

The electromagnetic wave with different orbital angular momentums exhibits potentials for new communication mechanism in both microwave and optical regains. In our recent research, we aim to generate orbital angular momentum waves using the idea of metastructures, for example, the metasurfaces operating as lenses. What's more, for the first time, the polarization property is added to design polarization-agile orbital angular momentum wave front, which is achieved using a two-layered metalenses proposed here. Theoretical and numerical analysis are carried out to validate the design. A new phase relation of metalens is synthesized by combining the radical distribution of aberration of lens and the rotated distribution of orbital angular momentum generation.