All-dielectric metasurface polarization scrambler for imaging applications

The partial polarization of the earth's radiation can be the source of radiometric errors for space instruments with polarization-sensitive components. It is therefore necessary to have a device capable of depolarizing the light before it enters the instrument, i.e., a polarization scrambler. Current scramblers used in optical payloads generally comprise combinations of prisms that enable spatial depolarization. However, polarization insensitivity comes at the cost of an inevitable degradation in imaging performance. Here we present a device based on an all-dielectric metasurface using anisotropic scatterers capable of generating multiple polarization states by varying their orientation angle. Our scrambling solution allows a massive reduction in the integrated degree of polarization and thus the spatial depolarization of any incident linear polarization, while reducing the impact on its image quality and allowing easier integration into the instrument design.