Symmetry Breaking in Non-Hermitian Plasmonic Lattices

2016年诺贝尔物理学奖授予David J. Thouless、F. Duncan M. Haldane和J. Michael Kosterlitz，以表彰他们在拓扑相变和物质拓扑相方面的理论发现。这里的术语拓扑是指当对象被拉伸、扭曲或变形时保持不变的属性。目前已开发的拓扑材料包括拓扑绝缘体和拓扑光子材料；这种材料有可能改变下一代电子产品和计算机。提出的实验和理论工作将侧重于实现涉及金属颗粒阵列的拓扑等离子体材料，这些材料可能在一系列光电器件中提供前所未有的功能。外展工作将把纳米光子学研究的进展融入大一学生的课堂，并与国家组织合作，促进基于个人故事和公共写作作品的科学。拓扑光子学是基于介质和磁性材料实现红外和微波波长对称保护特性的新兴领域，但与等离子体材料的联系很少。因此，损耗对拓扑保护边状态等性质的影响是未知的。此外，光子学理论的最新进展表明，这种技术上有趣的光学模式是可能的，本项目的一个主要重点是确定拓扑边缘状态是否可以使用非厄米模型预测，并在可见波长的混合等离子体晶格中实验实现。目标包括：(1)基于变形蜂窝晶格制造拓扑晶格，并使用非厄米模型和包括更高多极子的电动力学计算研究光学模式；(2)实现机械可调的拓扑晶格，建立畸变对平凡态和拓扑态之间可切换特性的影响；(3)测试表现出磁性等离子体响应的纳米粒子簇是否支持拓扑态；(4)研究具有增益区和可调谐耦合强度的等离子体晶格是否会破坏奇偶时间对称性。该奖项反映了美国国家科学基金会的法定使命，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。

The Nobel Prize in Physics in 2016 was awarded to David J. Thouless, F. Duncan M. Haldane, and J. Michael Kosterlitz for theoretical discoveries of topological phase transitions and topological phases of matter. The term topology here refers to a property that remains intact when an object is stretched, twisted, or deformed. Topological materials that have previously been developed include topological insulators and topological photonic materials; such materials have potential to transform next-generation electronics and computers. The proposed experimental and theoretical work will focus on realizing topological plasmonic materials involving arrays of metal particles that may offer unprecedented functionality in a range of optoelectronic devices. Outreach efforts will integrate nanophotonics research advances into the classroom for freshman students and working with national organizations to promote science based on personal stories and public writing pieces.Topological photonics is an emerging area for realizing symmetry-protected properties at infrared and microwave wavelengths based on dielectric and magnetic materials but has had little connection to plasmonic materials. Hence, the effects of losses on properties such as topologically protected edges states are unknown. Moreover, recent advances in photonics theory suggest that such technologically interesting optical modes could be possible, and a major focus of this project is to determine whether topological edge states can be predicted using non-Hermitian models and realized experimentally in hybrid plasmonic lattices at visible wavelengths. The objectives include: (1) fabricating topological lattices based on deformed honeycomb lattices and investigating optical modes using non-Hermitian models and electrodynamics calculations that include higher multipoles; (2) realizing mechanically tunable topological lattices and establishing effects of distortions on switchable properties between trivial and topological states; (3) testing whether nanoparticle clusters that exhibit magnetic plasmon responses can support topological states; and (4) investigating whether plasmonic lattices with patterned regions of gain and tunable coupling strength can break parity-time symmetry.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.