Detection of elliptical polarization parameters using a metalens

A metalens capable of detecting the polarization ellipticity of an incident beam is considered in this paper. This metalens consists of blocks with diffraction gratings of a 140-nm height and a 220-nm period. The metalens operates as a polarizer, which depends on one transverse coordinate, and a focuser. It is capable of both separating linearly polarized radiation into two focal spots with the opposite-handed circular polarizations and detecting the circular polarization handedness and degree of its ellipticity. Operating in a wide range of wavelengths from 0.55 to 0.837 µm, the metalens can be used in the range from 0.64 to 0.837 µm to identify the incident radiation wavelength due to an almost linear shift of the focal spot in the transverse plane with the wavelength.