Fabrication of High Performance Metasurfaces by Nanoimprinting of Refractive Index

这笔赠款支持促进与光学设备制造有关的知识的制造研究，这一努力促进了新兴技术的科学进步，具有促进国家健康、繁荣和国防的潜力。具体地说，这项研究推进了具有成本效益的纳米制造组件的关键能力，这种组件被称为亚表面，可以量身定做，通过几乎任意的波前整形控制来操纵光。这项重要技术在生物医学成像、光通信、激光成像检测和测距以及用于激光捕获和太阳能应用的光学管理等领域具有相关性。目前几乎所有可用于制造准表面的制造工艺都依赖于通过图案化、材料蚀刻或沉积来构造光学材料。这种通用的方法面临着基本的限制，这些限制影响了MetasSurface的性能、制造产量和可扩展性。该项目进行基础研究，研究一种创新的制造方法，在这种方法中，无需任何沉积或蚀刻，即可直接操纵材料的光学属性并以高分辨率进行图案化。除了支持现有亚表面结构的制造外，这种方法还独特地实现了新的亚表面设计，提供了卓越的操作带宽和制造公差。该奖项支持培训熟练工人进入科学、技术、工程和数学职业，支持本科水平的研究经验，提供将研究整合到本科课堂的机会，鼓励妇女和代表性不足的少数民族，并支持培养K-12学生对科学的兴趣的本地推广活动。这项工作的技术范围包括：(A)开发一种在纳米级芯片表面绘制折射率图案化的方法，(B)将多孔纳米材料的形态调节映射到有效的光学特性，(C)展示具有二元和任意折射率分布的高性能超表面的直接制造，以及(D)为非共振(宽带)相位控制提供了一种革命性的新方法，它克服了颗粒间距的限制，并提高了制造公差。这项研究集中在一种技术，即在多孔衬底上进行局部压印，并通过直接压印三维母版邮票来实现高分辨率的致密化，然后平面化。为了开发这种纳米制造方法，以实现高性能亚表面的成本效益制造，这项研究解决了工艺参数、工艺变化和控制、机械完整性、光学质量和工艺限制等关键问题。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This grant supports manufacturing research that advances knowledge pertaining to the fabrication of optical devices, an effort which promotes scientific progress in emerging technologies with the potential to advance national health, prosperity, and defense. Specifically, this research advances key capabilities in cost-effective nanomanufacturing of components known as metasurfaces, which can be tailored to manipulate light with almost arbitrary wavefront shaping control. This important technology holds relevance in areas such as biomedical imaging, optical communications, laser imaging detection and ranging, and optical management for laser trapping and solar energy applications. Nearly all currently available manufacturing processes for producing metasurfaces rely on structuring optical materials through patterning followed by material etching or deposition. This general approach faces fundamental limitations which impact metasurface performance, manufacturing yield, and scalability. This project conducts fundamental research that investigates an innovative fabrication pathway wherein a material's optical properties are directly manipulated and patterned at high resolution without any deposition or etching. In addition to supporting the fabrication of existing metasurface architectures this approach uniquely enables new metasurface designs offering superior operating bandwidths and fabrication tolerances. This award supports training of skilled workers to enter into science, technology, engineering, and math careers, provides support for research experiences at the undergraduate level, offers opportunities to integrate research within the undergraduate classroom, encourages women and underrepresented minorities and supports local outreach activities which fosters interest in science for K-12 students.The technical scope of this work includes: (a) developing a method for patterning refractive index on the surface of a chip with nanoscale resolution, (b) mapping the morphological tuning of porous nanomaterials to effective optical properties, (c) demonstrating the straight-forward fabrication of high performance metasurfaces with both binary and arbitrary refractive index profiles, and (d) offering a transformative new approach for non-resonant (broadband) phase control which overcomes interparticle spacing limitations and improves fabrication tolerance. This research focuses on a technique wherein porous substrates are locally imprinted and densified at high resolution by direct imprinting with three-dimensionally mastered stamps then planarized. With the aim of developing this nanomanufacturing approach to enable the cost effective fabrication of high performance metasurfaces, this research addresses key questions regarding process parameters, process variation and control, mechanical integrity, optical quality, and process limitations.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.