Random-phase metasurfaces at optical wavelengths.
Random-phase metasurfaces at optical wavelengths.
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DOI：
10.1038/srep28448
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发表时间：
2016-06-22
影响因子：
4.6
通讯作者：
Bozhevolnyi SI
中科院分区：
文献类型：
--
作者：
Pors A;Ding F;Chen Y;Radko IP;Bozhevolnyi SI
随机相位超颖表面（其中成分以随机相位散射光）具有入射平面波将漫散射的性质，从而导致最适合通过统计手段描述的复杂远场响应。在这项工作中，我们提出并验证了远场响应的统计描述，特别强调了偏振光和非偏振光的响应如何根据两个正交偏振的散射相位的相关性而相似或不同。通过利用基于间隙等离子体激元的超颖表面，由覆盖由亚波长薄玻璃间隔物和金纳米砖阵列的光学厚金膜组成，我们设计并实现了在800 nm波长的随机相位超颖表面。所制造的样品的光学特性令人信服地证明了漫散射的反射光，统计服从理论预测。我们预见使用随机相位超颖表面的伪装应用程序和高品质的参考结构，在暗场显微镜，而控制的统计偏振光和非偏振光可能会发现在安全应用中的用途。最后，通过将相邻超颖表面成分的散射之间的某种相关性结合起来，可以实现新类型的功能，例如朗伯反射器。
Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector.