Aix Marseille University, Université de Toulon, CNRS, IM2NP, Marseille, France.
Thales LAS France SAS, Élancourt, France.
Sci Rep. 2023 May 12;13(1):7770. doi: 10.1038/s41598-023-34579-w.
This paper presents the numerical simulation and fabrication of a metasurface composed of silver nanorings with a split-ring gap. These nanostructures can exhibit optically-induced magnetic responses with unique possibilities to control absorption at optical frequencies. The absorption coefficient of the silver nanoring was optimized by performing a parametric study with Finite Difference Time Domain (FDTD) simulations. The absorption and scattering cross sections of the nanostructures are numerically calculated to assess the impact of the inner and outer radii, the thickness and the split-ring gap of one nanoring, as well as the periodicity factor for a group of four nanorings. This showed full control on resonance peaks and absorption enhancement in the near infrared spectral range. The experimental fabrication of this metasurface made of an array of silver nanorings is achieved by e-beam lithography and metallization. Optical characterizations are then carried out and compared to the numerical simulations. In contrast to usual microwave split-ring resonator metasurfaces reported in literature, the present study shows both the realization by a top-down process and modelling performed in the infrared frequency range.
本文提出了一种由具有环形间隙的银纳米环组成的超表面的数值模拟和制造。这些纳米结构可以表现出光诱导的磁响应，具有独特的控制光学频率吸收的可能性。通过有限差分时域（FDTD）模拟进行参数研究，优化了银纳米环的吸收系数。数值计算了纳米结构的吸收和散射截面，以评估一个纳米环的内半径和外半径、厚度和环形间隙以及四个纳米环的周期性因子的影响。这表明可以完全控制近红外光谱范围内的共振峰和吸收增强。通过电子束光刻和金属化实现了由银纳米环阵列组成的这种超表面的实验制造。然后进行光学特性分析，并与数值模拟进行比较。与文献中报道的通常的微波环形谐振器超表面相比，本研究既展示了自上而下的制造过程，也展示了在红外频率范围内的建模。
