OP: MEMS-driven photonic metamaterials: dynamic wavefront tailoring with reconfigurable metasurfaces

A部分：该项目旨在开发由集成微机电系统（MEMS）致动器驱动的可调谐超材料，用于太赫兹和红外光的动态控制。光子超材料已被证明是操纵光传播的有力工具。然而，存在关于具有按需有效性质的随机存取超材料的开发的现有挑战。为了克服这一巨大挑战，MEMS致动器将与超材料单元集成，从而实现按需光操纵。相位控制，单位细胞，微/纳米纤维和系统集成方案的设计的物理将被调查，以实现超材料设备，可以操纵太赫兹和红外光的波前所需的，使，例如，动态光束转向和可调聚焦。将开发的超材料设备是多功能的，紧凑的，动态可调的，与传统的光学设备相比，提供了显着的潜力。该项目的成功将推动光谱学、高分辨率成像、光探测和测距（LiDAR）等领域光电系统的发展，这些领域广泛应用于医疗保健、国家安全和国防。该项目提供了一个平台，教育年轻的研究人员，包括妇女和代表性不足的少数民族，培养他们在基础光学和光子学研究和应用工程技术的热情。部分B：超材料已经彻底改变了电磁学在过去的十年中产生了无数的新现象，包括隐形，负折射率，和可调电磁复合材料。该项目的目标是开发动态可重构的超材料来操纵太赫兹和红外光的波前，这是通过在超材料单元中集成MEMS致动器来实现的。对于有效的波前操纵，关键是实现全跨度相位覆盖与恒定振幅的超材料单元的响应。然而，大多数超材料设计的振幅和相位响应是有界的，这使得实现高效波前操纵具有挑战性。在所提出的工作中，将研究超材料层与接地层或两层超材料之间的耦合效应，以设计能够调制相位响应而对幅度响应影响不大的结构，即解耦幅度和相位调制。将开发制造工艺，以基于表面和体微/纳米加工技术构建超材料器件。将研究和优化超材料单元和MEMS致动器的集成，以通过采用先进的MEMS集成和封装技术，包括三维布线，硅通孔（TSV）和倒装芯片键合，使每个单元可以单独访问。最后，展示多功能性的可调谐超材料设备将被证明可以操纵太赫兹和红外光。这包括动态光束转向和聚焦，这是最先进的技术无法实现的，适用于各种应用，如光谱学，成像和LiDAR。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Part A:This project aims to develop tunable metamaterials driven by integrated microelectromechanical system (MEMS) actuators for dynamic control of terahertz and infrared light. Photonic metamaterials have proven to be a powerful tool to manipulate light propagation. However, there is an existing challenge concerning the development of random access metamaterials with on-demand effective properties. In order to overcome this grand challenge, MEMS actuators will be integrated with metamaterial unit cells, enabling on-demand light manipulation. The physics of phase control, design of unit cells, micro-/nanofabrication, and system integration schemes will be investigated to realize metamaterial devices that can manipulate the wavefront of terahertz and infrared light as desired, enabling, for example, dynamic beam steering and tunable focusing. The metamaterial devices that will be developed are multifunctional, compact, and dynamically tunable, offering significant potential in comparison to conventional optical devices. The success of this project will boost the development of opto-electronic systems in areas such as spectroscopy, high-resolution imaging, and light detection and ranging (LiDAR), which are widely used in healthcare and national security and defense. This project provides a platform to educate young researchers, including women and underrepresented minorities, fostering their passion in fundamental optics and photonics research and applied engineering technologies.Part B:Metamaterials have revolutionized electromagnetism during the past decade resulting in myriad new phenomena including cloaking, negative refractive index, and tunable electromagnetic composites. The goal of this project is to develop dynamically reconfigurable metamaterials to manipulate the wavefront of terahertz and infrared light, which is enabled by integrating MEMS actuators in metamaterial unit cells. For efficient wavefront manipulation, the key is to achieve full-span phase coverage with constant amplitude in the response of metamaterial unit cells. However, the amplitude and phase response of the majority of metamaterial designs are bounded, making it challenging to achieve high-efficiency wavefront manipulation. In the proposed work, the coupling effect between the metamaterial layer and a ground plane or two layers of metamaterials will be studied to design structures that can modulate the phase response with little effect on the amplitude response, i.e. decoupling amplitude and phase modulation. Fabrication processes will be developed to construct metamaterial devices based on both surface and bulk micro-/nanomachining techniques. The integration of metamaterial unit cells and MEMS actuators will be investigated and optimized to make each unit cell accessible individually by employing advanced MEMS integration and packaging techniques including three-dimensional wire routing, through silicon vias (TSVs) and flip chip bonding. Finally, tunable metamaterial devices exhibiting multifunctionality will be demonstrated to manipulate terahertz and infrared light. This includes dynamic beam steering and focusing, which cannot be achieved with state-of-the-art techniques, for a variety of applications, such as spectroscopy, imaging, and LiDAR.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.