High-efficiency broadband pixelated polarization routers based on metalenses

Abstract

Polarization imaging is of particular significance in numerous fields ranging from underwater depth measurement, anti-counterfeiting to medical diagnosis. Metasurface-based polarizers have been efficiently demonstrated in various polarization measurements, which have great application prospects compared with traditional optical elements. However, Polarizers based on metalenses (i.e. metasurface lenses) are often designed to work in a single wavelength and are hard to work in a broadband wavelength region, which hinders practical imaging applications. Here, we designed a metalenses-based pixelated polarization router (PPR) that can be used as a full-Stokes polarizer for the whole visible wavelength range. As the PPRs are designed using polarization multiplexing to encode two different phase profiles and utilizing spatial multiplexing by the construction of a supercell, the transmittance and focusing efficiencies are calculated to be as high as ∼60% over the whole visible regime. The visible PPRs can be directly inserted between the Bayer color filter and the intensity-based photodetectors in a conventional imaging system, so that both the color and polarization information can be collected simultaneously.