TiO₂-coated guided-mode resonance gratings for polarization-selective green light filtering

Dielectric gratings with guided mode resonance (GMR) are integral to narrow-band filtering due to their high resonances, enhancing optical metrics like diffraction efficiency and sensitivity. Recent advancements have introduced polarization-sensitive GMR filters, enabling selective control of TE and TM mode resonances based on polarization. This work presents theoretical and experimental studies on a green filter using polarization-sensitive GMR gratings. These devices are pivotal in applications such as telecommunications, spectroscopy, and imaging. We demonstrate the fabrication of TiO₂-coated one-dimensional (1D) GMR gratings with polarizing resonance characteristics at normal incidence. A trapezoidal-profile grating, created via holographic lithography, achieves excellent polarization filtering for green light. Additionally, TiO₂-coated photoresist (PR) gratings on SiO₂ substrates are fabricated using magnetron sputtering, showcasing high performance and potential for cost-effective mass production. Nanoimprinting these gratings provides a scalable, economical method for producing reproducible GMR filters.