Ultra-Broadband Reflector Based On Subwavelength All-Dielectric Grating

We report the design an ultra-broadband highly reflective subwavelength grating that covers almost the entire visible region. Results show that high reflectivity above 90% covering 450-700 nm can be achieved, corresponding to Lambda lambda/lambda=43%. We also provide intuitive physical insights into the broadband high reflection performance of reflector. We expect that this ultra-thin, ultra-broadband and highly reflective all-dielectric reflector can find applications in hyperspectral imaging based on tunable etalon filters.