Single-shot optical multi-parameter detector based on dielectric metalens array

The measurement of the polarizations and phase profiles of a light beam in one shot is of crucial importance for fundamental researches and daily life. Recently, optical metasurfaces, the ultrathin inhomogeneous interface made of planner nanostructure arrays, have become multi-functional and compact platforms for various emerging applications. Here, we propose and demonstrate an integrated, ultra-compact and miniaturized optical multi-parameter detector, based on efficient metalens arrays featuring the basic pixel composed of 2×2 polarization-dependent metalenses. This multifunctional detector determines not only the spatially variant polarizations through relative focusing intensities, but also the phase gradient profiles via submicron displacements of focal points. To demonstrate its performance, we experimentally measure the beams of 18 scalar polarizations and 7 tilted wavefronts with our system, showing average relative errors of as low as 3.89% for polarization detections and 3.72% for phase gradient detections. Our work can be applied to polarization imaging, optical element topography diagnosis, complex structure light detection, target recognition and health care.