Self-supported subwavelength gratings with a broad band of high reflectance analysed by the rigorous coupled-wave method

Based on rigorous electromagnetic theory and the coupled-wave method, the reflectance performance of the self-supported subwavelength grating (SSG) with different geometrical and physical parameters, such as the incident wavelength, the grating period, the grating thickness, the filling ratio of the grating, the incident angle, and the refractive index of the outer space, is systematically investigated. For TE polarization, numerical results reveal that a very broad band (Δλ/λ=26.13%) of high reflectance ( R>99% ) is achieved in the near-infrared region. Motivated by the micro-electromechanical systems actuator, the SSG is expected to have extensive potential applications in many optoelectronic devices including tunable optical mirrors or filters.