Liu Li, Holzer Aaron, Raney Neal, Babicheva Viktoriia E
Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico, 87131, USA.
Sci Rep. 2025 Aug 11;15(1):29339. doi: 10.1038/s41598-025-12996-3.
The precision and reproducibility in the fabrication of periodic nanoantenna arrays are crucial for metasurfaces to achieve consistent and controllable optical responses, and electron beam lithography (EBL) enables this by providing patterning with high resolution down to the nanoscale. This work explores the impact of EBL exposure on the size and uniformity of nanoantennas in periodic arrays, with a focus on the role of substrate conductivity. By systematically comparing substrates with different levels of electrical conductivity, we examine how variations in electron scattering and charge accumulation affect the precision and dimensional control of the fabricated nanoantennas. We show that exposure can efficiently tune the optical characteristics of metasurfaces composed of such nanoantennas, with various multipolar resonances appearing in the spectra of the titanium-based metasurfaces. Titanium is chosen as a nanoantenna material because it provides robust operation in high-temperature environments and biologically relevant applications, while the supported multipolar resonances enhanced by the collective effect offer a versatile platform for engineering the metasurface spectral response. We demonstrate how substrate conductivity influences patterning outcomes, metasurface multipolar resonances, and manifestation of generalized Kerker effect, highlighting the need to carefully select exposure parameters and the underlying material. This work provides insights to improve the fabrication of periodic nanoantenna arrays, ensuring uniformity and consistent optical performance of the metasurfaces based on them.
周期性纳米天线阵列制造过程中的精度和可重复性对于超表面实现一致且可控的光学响应至关重要，而电子束光刻（EBL）通过提供低至纳米级的高分辨率图案化来实现这一点。这项工作探讨了EBL曝光对周期性阵列中纳米天线尺寸和均匀性的影响，重点关注衬底电导率的作用。通过系统地比较具有不同电导率水平的衬底，我们研究了电子散射和电荷积累的变化如何影响所制造纳米天线的精度和尺寸控制。我们表明，曝光可以有效地调节由此类纳米天线组成的超表面的光学特性，钛基超表面的光谱中会出现各种多极共振。选择钛作为纳米天线材料是因为它在高温环境和生物相关应用中能稳定工作，而集体效应增强的多极共振为设计超表面光谱响应提供了一个通用平台。我们展示了衬底电导率如何影响图案化结果、超表面多极共振以及广义克尔效应的表现，强调了仔细选择曝光参数和底层材料的必要性。这项工作为改进周期性纳米天线阵列的制造提供了见解，确保基于它们的超表面具有均匀性和一致的光学性能。
