An antireflective coating presenting a continuous refractive index gradient is theoretically better than its discrete counterpart because it can give rise to a perfect broadband transparency. This kind of surface treatment can be obtained with nanostructures like moth-eye. Despite the light scattering behavior must be accounted as it can lead to a significant transmittance drop, no methods are actually available to anticipate scattering losses in such nanostructured antireflective coatings. To overcome this current limitation, we present here an original way to simulate the scattering losses in these systems and routes to optimize the transparency. This method, which was validated by a comparative study of coatings presenting refractive indices with either discrete or continuous gradient, shows that a discrete antireflective coating bilayer made by oblique angle deposition allows reaching ultra-high mean transmittance of 98.97% over the broadband [400-1800] nm. Such simple surface treatment outperforms moth-eye architectures thanks to both interference effect and small dimensions nanostructures that minimize the scattering losses as confirmed by finite-difference time domain simulations performed on reconstructed volumes obtained from electron tomography experiments.

中文翻译：

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光散射对高性能纳米结构抗反射表面的重要性

具有连续折射率梯度的抗反射涂层在理论上比其离散对应物更好，因为它可以产生完美的宽带透明度。这种表面处理可以通过类似蛾眼的纳米结构来获得。尽管必须考虑光散射行为，因为它会导致显着的透射率下降，但实际上没有方法可以预测此类纳米结构抗反射涂层中的散射损失。为了克服这个电流限制，我们在这里提出了一种原始方法来模拟这些系统中的散射损失和路径以优化透明度。该方法通过对具有离散或连续梯度的折射率的涂层进行比较研究而得到验证，表明通过斜角沉积制成的离散抗反射涂层双层允许在宽带 [400-1800] nm 上达到 98.97% 的超高平均透射率。这种简单的表面处理优于蛾眼结构，这要归功于干涉效应和小尺寸纳米结构，它们最大限度地减少了散射损失，正如对从电子断层扫描实验获得的重建体积执行的有限差分时域模拟所证实的那样。