Cascaded metamaterial polarizers for the visible region

Polarizers serve many application fields such as imaging, display technology, and telecommunications. Focusing on the visible spectral region, we provide the design and fabrication of compact high-efficiency resonant polarizers in the crystalline silicon-on-quartz material system. We experimentally verify the improved efficiency attained by a cascaded dual-module polarizer assembled with building blocks of elemental subwavelength grating structures. We obtain a measured extinction ratio (ER) of ∼3000 in a 2 mm thick stacked prototype device across a bandwidth of ∼110nm in the 570-680 nm spectral domain. The ridge width of the constituent nanograting is ∼84nm. Computed results show a high ER in spite of the lossy nature of crystalline silicon in the visible region, enabling cascaded metasurfaces while preserving high transmission.