Investigation of electromagnetic properties of terahertzmeta-surfaces tunable using multidirectional magneticfield

利用多向磁场可调谐太赫兹超表面的电磁特性研究

• 批准号: 525135725
• 负责人: Professor Dr. Ulrich Mescheder
• 金额: --
• 依托单位: Institut für Angewandte Forschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/525135725?language=en
• 关键词: Investigation; electromagnetic; properties; terahertzmeta; surfaces

The project’s primary scientific goal is to develop cantilevered, magnetic field reconfigurable terahertz meta-surfaces (MS) based on an understanding of the dependence of their electromagnetic properties as well as the interaction of the MS with electromagnetic waves (EMW) in the THz-range on the design parameters of the MS. The propagation and interactions of EMW in materials in the THz frequency range (0.1-10 THz) i is subject of current international research. Tremendous progress has been made in this field over the last two decades, including the invention of photoconductive antennas (PCAs) that enable pulsed excitation and thus Time Domain Spectroscopy (TDS). Among these, so-called metamaterials (MM) are among the fastest growing areas in the THz range. A MM is an artificial material consisting of periodical or quasi-periodical arranged structures with sizes smaller than the wavelength and which can take on properties not found in natural materials, e.g., both negative refractive index and negative permeability, which are called double negative structures (DNG). This opens up new possibilities for interaction with EMW. Meta-surfaces (MS) are two-dimensional MM. Their properties can be either already determined by design and fabrication or actively modifiable (by external stimuli such as light, electric current or potential, temperature). One way to reconfigure MS is to use magnetic field-driven microelectromechanical systems (MF-MEMS), in which structural elements are deformed by an external magnetic field. MEMS are used, e.g. for switching light, as micro mirror actuators, and in sensing applications. However, their application for tunable THz-MS has been very limited so far. In the proposed project, the driving magnetic field vector will be freely controllable by an external excitation system. MEMS-based THz MS structures will be developed which can interact with the magnetic field in any direction. The MS’s structural elements will consist of conducting and magnetic microbeams that are magnetically deformable. The deformation of the structural elements will affect the electromagnetic properties of the MS in the THz range, especially transmission, reflection (changes in resonance frequencies) and polarization. The design of the structural elements has a significant impact on the electromagnetic properties of MS. Those designs are sought that produce a large change in EM properties (e.g., resonant frequency) in the THz range. Also, the optimal MEMS fabrication processes for deformable microstructures made of magnetic materials will be investigated. Technological and scientific issues: 1) Optimal surface designs for effective magnetic reconfigurability in the THz range; 2) Influence of geometrical and magnetic properties of MS structures on their effective interactivity with THz radiation and dynamic behavior; 3) Exploration of MEMS techniques for secondary reconfiguration of the MS; 4) Long-term and alternating load stability.

该项目的主要科学目标是开发悬臂式，磁场可重构太赫兹超表面（MS）的设计基于对它们的电磁特性以及MS与太赫兹范围内的电磁波（EMW）的相互作用对MS的设计参数的依赖性的理解。（0.1-10 THz）i是当前国际研究的主题。在过去的二十年里，该领域取得了巨大的进步，包括光电导天线（PCA）的发明，它使脉冲激发和时域光谱（TDS）成为可能。其中，所谓的超材料（MM）是THz范围内增长最快的领域之一。MM是由尺寸小于波长的周期性或准周期性排列的结构组成的人造材料，并且其可以呈现天然材料中没有的性质，例如，同时具有负折射率和负磁导率，称为双负结构（DNG）。这为与EMW的互动开辟了新的可能性。元表面（MS）是二维MM。它们的属性可以通过设计和制造来确定，也可以通过外部刺激（如光、电流或电势、温度）来主动修改。重新配置MS的一种方法是使用磁场驱动的微机电系统（MF-MEMS），其中结构元件通过外部磁场变形。MEMS例如用于切换光、用作微镜致动器以及用于感测应用中。然而，到目前为止，它们在可调谐THz-MS中的应用非常有限。在拟议的项目中，驱动磁场矢量将通过外部激励系统自由控制。基于MEMS的THz MS结构将被开发，它可以在任何方向上与磁场相互作用。MS的结构元件将由可磁性变形的导电和磁性微梁组成。结构元件的变形将影响MS在THz范围内的电磁特性，特别是透射、反射（谐振频率的变化）和偏振。结构元件的设计对MS的电磁特性具有显著影响。寻求产生EM特性的大的变化的那些设计（例如，谐振频率）在太赫兹范围内。此外，最佳的MEMS制造工艺的磁性材料制成的可变形微结构将进行研究。技术和科学问题：1）在太赫兹范围内有效磁重构的最佳表面设计; 2）MS结构的几何和磁特性对其与太赫兹辐射和动态行为的有效相互作用的影响; 3）探索用于MS二次重构的MEMS技术; 4）长期和交变负载稳定性。