  To define and characterize optical systems, obtaining information on the
amplitude, phase, and polarization profile of optical beams is of utmost
importance. Polarimetry using bulk optics is well established to characterize
the polarization state. Recently, metasurfaces and metalenses have successfully
been introduced as compact optical components. Here, we take the metasurface
concept to the system level by realizing arrays of metalens 2*3 sub-arrays,
allowing to determine the polarization profile of an optical beam. We use
silicon-based metalenses with a numerical aperture of 0.32 and a mean measured
diffraction efficiency in transmission mode of 28% at 1550 nm wavelength.
Together with a standard camera recording the array foci, our system is
extremely compact and allows for real-time beam diagnostics by inspecting the
foci amplitudes. By further analyzing the foci displacements in the spirit of a
Hartmann-Shack wavefront sensor, we can simultaneously detect phase-gradient
profiles. As application examples, we diagnose the polarization profiles of a
radially polarized beam, an azimuthally polarized beam, and of a vortex beam.
