Design and Fabrication of Highly Selective Polarizers Using Metallic-Dielectric Gratings

Polarization imaging has been proven as an important technique for obtaining multi-dimensional information in complex environments. As the prevalent polarizers, metal gratings are widely used especially for focal-plane detection due to their flexibility and easy integration. However, high-performance polarization gratings with high transmittance and large extinction ratios typically need a large aspect ratio in design, resulting in more difficulties in fabrication with limited practical performances. In this study, we designed and fabricated a high-performance polarizer using metallic-dielectric gratings (MDGs). Through a single CMOS-compatible procedure that included electron-beam lithography (EBL) and a collimated thermal evaporation deposition process, we achieved a high TM transmittance (similar to 90%) and a high extinction ratio (similar to 100:1) in the experiment. We believe that our work provides an effective approach to high-performance polarization gratings, which could contribute to the development of on-chip integrated polarization imaging.