设计了一种光纤通信波段的纳米抗反射结构。采用有限时域差分(FDTD)优化模拟算法,寻找在1250 nm到1650 nm波长范围内能够显著降低反射率的蛾眼纳米结构。开发了一种多目标优化算法,将宽带反射率在0°到30°的入射角范围内进行了优化。对结构中纳米柱的几何排列、半径、高度和周期组成的参数空间进行了完整的搜索。在波长为1550 nm时,仿真得到接近零的反射率为0.012%。对该设计采用了纳米压印进行实验验证,对于最佳设计的样品,在1550 nm处测量获得了低至0.157%的反射率。分析了模拟结果与实验测量之间的差异,并结合反射率对波长的变化进行了分析。

In this study, we design nanostructured antireflection multiwavelength micro-optics that can be used in fiber-optic communication systems. The finite-difference time-domain method was used to search for a moth-eye nanostructure that exhibited a significantly reduced reflectivity in the wavelength range from 1250 to 1650 nm. Further, a multiobjective optimization algorithm was developed for optimizing the wideband reflectance at an oblique incidence from 0° to 30°; this optimization was implemented for a parameter space in which the geometrical arrangement, radius, height, and period of the nanopillars could be included. Subsequently, at a wavelength of 1550 nm, a near-zero reflectance (0.012%) was obtained via simulation, whereas an experimental value of 0.157% was obtained when the samples fabricated based on the optimal design was used. Furthermore, this discrepancy between the simulated and experimental results was analyzed by considering the change in the reflective index with the wavelength.