Materials World Network: Classical and Quantum Optical Metamaterials by Combining Top-down and Bottom-up Fabrication Techniques

技术综述：得益于微纳米加工工具的进步，超材料的研究最近已从微波扩展到太赫兹和光学频率。超材料的缩小以满足光学频率，为一类新的超材料铺平了道路，即量子超材料，这可能对电信、光学成像、能源采集、医疗保健和国土安全的广泛应用产生深远影响。然而，光学超材料领域的进一步突破受到以下几个因素的阻碍：(1)目前自上而下的制造技术无法设计出几个纳米级的结构；(2)利用自下而上的纳米制造方法缺乏长程有序化；(3)金属基光学超材料的光学损失；(4)光学超材料在低光子能级下缺乏光学控制。在这个项目中，科学家们的目标是通过将自上而下和自下而上的纳米制造技术相结合来制造光学超材料，并将超材料扩展到量子区域以减少损失，并引入超越经典超材料的新型光学控制方案来解决上述问题。该项目协同结合了三位合作者，两位在英国，一位在美国，研究新型经典和量子光学超材料的制造、表征和建模。这个合作小组的核心原理是，它将一个在大规模纳米制造方面拥有专业知识的英国小组，一个在非线性光学领域展示理论能力的英国小组，与一个在各种光学表征技术方面证明有记录的美国小组相匹配。非技术摘要：超材料是模仿物质顺序的人造材料。超材料由人工设计的“原子”和“分子”组成，它们可以被设计成显示自然产生的材料无法获得的光学特性。超材料提供了一种新的平台，可以随意控制光线，具有潜在的应用前景，例如可以打破成像衍射极限的强大成像透镜，以及使外部观察者看不到物体的隐形斗篷。通过引入一种新的纳米制造范式，这一合作项目旨在解决阻碍超材料实际应用的问题，并弥合实验室概念验证演示与现实世界应用之间的差距。将在这里进行的研究具有几个广泛影响的领域。首先，它将促进基础材料科学的跨学科考试，其中包括制造、材料物理、光学物理和理论。其次，它将使美国和英国的三个组织能够进行合作，这三个组织有着深厚的互动历史，并拥有互补的专业知识和能力。这项工作为研究生和本科生提供了在国际环境中合作和旅行的机会。第三，该项目有具体的计划和程序来寻找不同的学生合作者的招募。第四，该项目使学生能够通过延长访问和缩短行程与主要的国家实验室合作，即劳伦斯·伯克利实验室，其中一名PI是一名学术人员，以及伦敦纳米技术中心，英国首屈一指的纳米制造设施，由伦敦大学学院和伦敦帝国理工学院共享。该项目得到电子和光子材料计划和材料研究部特殊计划办公室的支持。

TECHNICAL SUMMARY:Benefiting from advancement of micro and nanofabrication tools, the research in metamaterials has been recently extended from microwave to terahertz and optical frequencies. The scale-down of metamaterials to meet optical frequencies, paves the way for a new class of metamaterials, namely quantum metamaterials, which could have a profound impact on a broad range of applications in telecommunication, optical imaging, energy harvesting, health care, and homeland security. However, further breakthrough in the field of optical metamaterials is hindered by several factors: (1) the capability of current top-down fabrication techniques to engineer structures at a few nanometers scale; (2) lack of long range ordering by using the bottom up nanofabrication approaches; (3) optical loss in the metal-based optical metamaterials; (4) lack of optical control at low photon levels in optical metamaterials. In this project, scientists aim to solve the above issues by combining top-down and bottom-up nanofabrication techniques for the manufacturing of optical metamaterials, and by extending metamaterials to the quantum regime to reduce the loss and to introduce novel optical control schemes that go beyond classical metamaterials. This project combines synergistically three collaborators, two in the UK and one in the US, to investigate the fabrication, characterization and modeling of novel classical and quantum optical metamaterials. The central rationale for this collaborative group is that it matches a UK group with expertise in large scale nanofabrication, a UK group in demonstrated theoretical capabilities in nonlinear optics, with a US group with demonstrated record of various optical characterization techniques. NON-TECHNICAL SUMMARY:Metamaterials are man-made materials that mimic the order of the matters. Metamaterials consist of artificially engineered "atoms" and "molecules", which can be designed to show optical properties unattainable from naturally occurring materials. Metamaterials present a novel platform for controlling light at one's will with potential applications such as a powerful imaging lens that beats the imaging diffraction limit and an invisibility cloak that renders object invisible to outside observers. By introducing a novel nanofabrication paradigm, this collaborative project aims at solving the issues that hinder the practical application of metamaterials, and bridging the gap between the proof-of-concept demonstrations in the laboratory to real world applications. The research to be undertaken here has several areas of broad impact. First, it will foster an interdisciplinary examination of the fundamental materials science, which includes fabrication, materials physics, optical physics, and theory. Second it will enable three groups in the US and the UK, with a strong history of interactions and complementary expertise and capabilities to collaborate. This work involves the opportunity for both graduate and undergraduate students to collaborate and travel in an international setting. Third, the program has concrete plans and procedures to seek out recruitment of diverse student collaborators. Fourth, the project enables students to collaborate via extended visits and shorter trips with a major National Laboratory, i.e. Lawrence Berkeley Lab, where one of the PIs was an academic staff, as well as the London Centre for Nanotechnology, UK's premier nanofabrication facility shared by the University College London and Imperial College London.This project is supported by the Electronic and Photonic Materials program and Office of Special Programs, Division of Materials Research.