A broadband polarization splitting device with sub-micron sized pixels

Abstract

Integration of polarization sensing into conventional imaging devices can uncover crucial information, unlocking applications across a wide range of scientific domains from biomedical imaging to remote sensing and astronomy. Rapid progress in nanofabrication technology has driven the trend of pixel downscaling in imaging devices, leading to improved device functionality and performance. For polarization imaging to engage with high-resolution image sensor a further scaling of per-pixel polarizing objects is needed, while maintaining the optical throughput. In this paper, we propose a design for an ultracompact polarization splitting device based on a vertical dielectric waveguide architecture, compatible with sub-micron pixel sizes (560 nm), which is close to the state-of-the-art CMOS imager sensor resolution. The device implements an adiabatic mode converter to effectively separate orthogonal linear polarization states of incident light across the entire visible spectrum. Moreover, we demonstrate the design versatility by expanding its polarization splitting functionality across the entire linear polarization space (0 degrees-180 degrees), enabling robust polarization detection for advanced polarization imaging applications.