亚波长纳米结构宽波段抗反射特性

Design of the wideband anti-reflective subwavelength nanostructures

研究了玻璃(折射率n=1.52)表面周期性台阶结构的宽波段抗反射特性。利用等效媒质理论,对单台阶和二台阶结构进行了参数设计,并用严格耦合波理论对设计的台阶结构进行了入射光波长、入射角的反射效率、反射级次特性分析计算。研究结果表明:当亚波长纳米结构的周期低于周期阈值时,随着入射波长的增加只有零级衍射;台阶层数的增加,可增加红外抗反射入射波长和入射角的范围。二台阶结构可以在可见光和整个红外波段的反射率都低于1%。在玻璃表面上制备的台阶结构和基底为一体,这种方法克服了抗反射膜层的许多不足,其附着力、抗蚀刻、渗透扩散等问题均不存在,适用于受温度和湿度等环境因素影响较大的可见光及红外抗反射器件的设计和制作工艺中。

The anti-reflectivity of sub-wavelength glass （Rafractive index n is 1.52） with single-step and double-step nanostructures was designed using the effetive medium theory. The incident wavelengh the reflection efficiency of incident angle and the properties of reflection grades were analyzed with the rigorous coupled-wave theory. The result shows that the subwavelength structure would only produce the zeroth order with the increasing of the incident wavelength when the period of nanometer structure for the light wavelength was less than the threshold. When the phase level was increased, the incident wavelength and the incident angle range of the infrared anti-reflection were also increased. When the nanostructure is in double-step, the reflectivity is less than 1% in visible light and all infrared wave band. The method of perpetrating step structure on the glass surface can overcome many deficiencies of anti-reflective film, for example, the adhesion between the step structures and the substrate are good, and the penetration and diffusion of the anti- reflective layers＇ components don＇t exist. It is suitable for the visible and infrared anti-reflective device＇s design and production process that influenced by temperature, humidity and other environmental factors.