Polarizing mirror/absorber for visible wavelengths based on a silicon subwavelength grating: design and fabrication

A one-dimensional 280-nm period silicon grating designed to exhibitpolarization-dependent reflection or antireflection behavior at visiblewavelengths has been fabricated and tested. For normally incident575-nm light, this grating reflects less than 3% of the incidentradiation polarized perpendicular to the grating grooves andapproximately 23% of the orthogonal polarization. To demonstratethe grating's broadband characteristics, reflectance measurements arepresented over the free-space wavelength range 475 nm < lambda(0) < 800 nm, for angles of incidence in the range 0 degrees < theta < 40 degrees , for polarization parallel and perpendicular to thegrating grooves, and for planes of incidence parallel and perpendicularto the grooves. A description of the fabrication process is alsogiven.