EAGER: Engineering light-matter interaction via topological phase transitions in photonic heterostructures with aperiodic order

非技术性描述：使用工程光学纳米结构增强光-物质相互作用过程，例如光子的发射和吸收，是维持包括光源、调制器和光学传感器在内的许多有源器件持续发展的关键特征。这些设备是我们当前信息时代的基石，高度集成的半导体芯片以不断增长的速度传递和操纵光和电信号，直接或间接地影响我们社会的各个方面。在这个项目中，我们提出了一种新的方法来提高光-物质相互作用，并定制的基本传输过程，在光学纳米结构的光子动力学。特别是，我们计划利用电子系统中最近发现的拓扑相的跨学科物理学，设计具有前所未有的光学特性的发光光子纳米结构。拓扑绝缘体是这种迷人结构的一个例子，它是一种内部表现为电绝缘体的材料，但可以在其表面上牢固地导电，而不管扰动和无序。我们的项目探讨了这种系统的光子类似物扩展到非周期性的几何形状，支持本地化的场解，大大增强了光-物质耦合，并产生了新的光子输运特性。我们研究计划的成功开发可能会在有源硅光子学的技术战略领域取得多项突破，从而可能在具有成本效益的硅芯片上实现光信号产生、传播、处理和能量收集的变革性设备应用。该项目的科学也为本科生和研究生水平的充满活力的教育和推广计划的发展提供了令人兴奋的机会。技术说明：我们的提案结合了确定性非周期系统的拓扑理论，复杂光子结构的器件级电磁建模，材料和器件制造与基于硅技术的发光纳米结构的光谱表征的跨学科观点。该提案建立在最近的理论进展基础上，这些理论进展在二维拓扑绝缘体和一维光子准晶体的丰富物理学之间建立了令人惊讶的联系。在这个项目中，我们将把这个愿景扩展到更一般的非周期系统，我们将通过平滑连接有源波导结构与不等效拓扑来设计拓扑相变。这种设备将使用广泛的硅技术制造，以保证大批量和低成本生产。我们的目标将通过首先制造低损耗硅兼容材料来实现，例如掺杂发光稀土离子的透明导电氧化物和氮化物以及Si量子点。然后，我们将制作亚波长缝隙波导光栅结构的非周期性折射率调制，将可控地实现不同类型的拓扑转换。理解这种渐变非周期系统中光波的理论基础将与材料和器件的实验表征密切合作。特别是，严格的电磁理论和设备级建模的制造结构将被执行。将通过稳态和时间分辨荧光光谱结合材料的结构表征来研究制造样品的光发射和传输特性。这项工作为一类新型的光子材料铺平了道路，这些材料利用拓扑效应和非周期性顺序来操纵有源纳米结构中的光子传输和光局域化现象。此外，这项研究可以导致在纳米光子学中发现新的表面现象，并将使新的策略的发展，以促进光与物质的相互作用在非周期性系统的发射特性本质上决定了其拓扑不变量的性质。

Nontechnical description: Enhancing light-matter interaction processes such as the emission and absorption of photons using engineered optical nanostructures is a key feature to sustain the continuing development of a number of active devices that include light sources, modulators and optical sensors. These devices are the cornerstones of our present information age, where highly integrated semiconductor chips deliver and manipulate optical and electrical signals at ever increasing rates, directly or indirectly affecting every aspect of our society. In this project we propose a novel approach to boost light-matter interaction and tailor the fundamental transport processes that govern the photon dynamics in optical nanostructures. In particular we plan to engineer light-emitting photonic nanostructures with unprecedented optical properties by leveraging the interdisciplinary physics of the recently discovered topological phases in electronic systems. An example of such fascinating structures is provided by topological insulators, which are materials that behave as electrical insulators in their interior but can robustly conduct electricity on their surface irrespectively of perturbations and disorder. Our project explores photonic analogues of such systems extended to non-periodic geometries that support localized field solutions with greatly enhanced light-matter coupling and give rise to novel photon transport properties. The successful development of our research program may lead to a number of breakthroughs in the technologically strategic area of active silicon photonics, potentially resulting in transformative device applications to optical signal generation, propagation, processing and energy harvesting on the cost-effective silicon chip. The science of this project also offers exciting opportunities for the development of a vibrant educational and outreach plan on undergraduate and graduate levels. Technical description: Our proposal combines interdisciplinary perspectives on topological theory of deterministic aperiodic systems, device-level electromagnetic modeling of complex photonic structures, materials and device fabrication with spectroscopic characterization of light-emitting nanostructures based on silicon technology. The proposal builds on recent theoretical advancements that established a surprising connection between the rich physics of two-dimensional topological insulators and one-dimensional photonic quasi-crystals. In the project we will extend this vision to more general aperiodic systems and we will engineer topological phase transitions by smoothly connecting active waveguide structures with inequivalent topologies. Such devices will be fabricated using the widespread silicon technology that guarantees high-volume and low-cost production. Our goals will be achieved by first fabricating low-loss silicon compatible materials, such as transparent conductive oxides and nitrides doped with light emitting rare earth ions and Si quantum dots. We will then fabricate sub-wavelength slot waveguide gratings structures with aperiodic refractive index modulations that will controllably implement different types of topological transitions. The theoretical foundation to understand optical waves in such graded aperiodic systems will be developed in close partnership with experimental characterization of materials and devices. In particular, rigorous electromagnetic theory of and device-level modeling of the fabricated structures will be performed. The optical emission and transport properties of fabricated samples will be investigated by steady-state and time-resolved fluorescence spectroscopy in combination with structural characterization of materials. The proposed work paves the way to a novel class of photonic materials that leverage topological effects and aperiodic order to manipulate photon transport and light localization phenomena in active nanostructures. Moreover, this research can result in the discovery of novel surface phenomena in nanophotonics and will enable the development of new strategies to boost light-matter interaction in aperiodic systems with emission characteristics intrinsically determined by the nature of their topological invariants.