Sterl Florian, Herkert Ediz, Both Steffen, Weiss Thomas, Giessen Harald
4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.
ACS Nano. 2021 Jun 22;15(6):10318-10327. doi: 10.1021/acsnano.1c02538. Epub 2021 Jun 11.
The optical properties of plasmonic nanoparticle ensembles are determined not only by the particle shape and size but also by the nanoantenna arrangement. To investigate the influence of the spatial ordering on the far-field optical properties of nanoparticle ensembles, we introduce a disorder model that encompasses both "frozen-phonon" and correlated disorder. We present experimental as well as computational approaches to gain a better understanding of the impact of disorder. A designated Fourier microscopy setup allows us to record the real- and Fourier-space images of plasmonic metasurfaces as either RGB images or fully wavelength-resolved data sets. Furthermore, by treating the nanoparticles as dipoles, we calculate the electric field based on dipole-dipole interaction, extract the far-field response, and convert it to RGB images. Our results reveal how the different disorder parameters shape the optical far field and thus define the optical appearance of a disordered metasurface and show that the relatively simple dipole approximation is able to reproduce the far-field behavior accurately. These insights can be used for engineering metasurfaces with tailored disorder to produce a desired bidirectional reflectance distribution function.
等离子体纳米颗粒集合体的光学性质不仅取决于颗粒的形状和大小，还取决于纳米天线的排列方式。为了研究空间有序性对纳米颗粒集合体远场光学性质的影响，我们引入了一个包含“冻结声子”和相关无序性的无序模型。我们提出了实验和计算方法，以便更好地理解无序性的影响。一种指定的傅里叶显微镜设置使我们能够将等离子体超表面的实空间和傅里叶空间图像记录为RGB图像或全波长分辨数据集。此外，通过将纳米颗粒视为偶极子，我们基于偶极子-偶极子相互作用计算电场，提取远场响应，并将其转换为RGB图像。我们的结果揭示了不同的无序参数如何塑造光学远场，从而定义无序超表面的光学外观，并表明相对简单的偶极近似能够准确地再现远场行为。这些见解可用于设计具有定制无序性的超表面，以产生所需的双向反射分布函数。
