High reflectivity broadband infrared mirrors with all dielectric subwavelength gratings

A high reflectivity (>99%) subwavelength grating mirror (SWGM), yields a very broad reflection spectrum (1.3-2.1 μm), has been designed for parallel polarized (p-polarized) incident light and evaluated by rigorous electromagnetic simulations. Design-sensitive analysis was made by varying one parameter at one time while keeping the other constant. The operating region of the grating mirror can be adjusted by varying the parameters of grating. The results show that the broadband reflection is unaffected by the refractive index and the thickness of the low index material, which is different from the previous conclusions. Because of its ease of fabrication, the mirror can be integrated with any photonic component with a flat surface, which has potential applications for active and passive photonic devices.