Double grating antireflection nanostructure based on nano-cone

A type of half-embedded cone grating nanostructure is proposed for antireflection (AR). It can achieve reflectance of down to 0.5% under normal incidence and 6% under incidence angle as large as 40 degrees in the 300-1100 nm wavelength range. Besides, it can maintain good performance in a large dimension range with a fixed period or vertex angle. Furthermore, the refractive index of the grating can be varied in a large range while keeping the high antireflective ability, namely that the material of the grating can be freely chosen without the limitation of single material. More importantly, it can tolerates the interlayer between the double cone grating much with just a slightly fluctuation of the reflectance less than 0.03%. These properties reduce both the design difficulty and the fabrication difficulty, making it a potential solution for use in various applications such as renewable energy and optical-electro devices.