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

非技术描述：利用工程光学纳米结构增强光-物质相互作用过程，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。这些设备是我们当今信息时代的基石，在这个时代，高度集成的半导体芯片以越来越快的速度传递和操纵光学和电子信号，直接或间接地影响着我们社会的方方面面。在这个项目中，我们提出了一种新的方法来促进光-物质相互作用，并定制控制光学纳米结构中光子动力学的基本传输过程。特别是，我们计划利用最近在电子系统中发现的拓扑相的跨学科物理学来设计具有前所未有光学特性的发光光子纳米结构。拓扑绝缘体提供了这种迷人结构的一个例子，这种材料在其内部表现为电绝缘体，但无论扰动和无序如何，都能在其表面上牢固地导电。我们的项目探索这种系统的光子类似物扩展到非周期几何，支持局域场解决方案，大大增强了光-物质耦合，并产生了新的光子传输特性。我们的研究项目的成功发展可能会导致有源硅光子学技术战略领域的一系列突破，潜在地导致在具有成本效益的硅芯片上的光信号产生、传播、处理和能量收集的变革性设备应用。这个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。技术描述：我们的提案结合了确定性非周期系统拓扑理论的跨学科观点，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。该提议建立在最近的理论进展之上，该进展在二维拓扑绝缘体和一维光子准晶体的丰富物理之间建立了令人惊讶的联系。在该项目中，我们将把这一愿景扩展到更一般的非周期系统，我们将通过将有源波导结构与非等效拓扑平滑连接来设计拓扑相变。这种装置将使用广泛使用的硅技术制造，以保证大批量和低成本的生产。我们的目标将通过首先制造低损耗硅兼容材料来实现，例如透明导电氧化物和掺有发光稀土离子和硅量子点的氮化物。然后，我们将制造具有非周期折射率调制的亚波长缝隙波导光栅结构，该结构将可控地实现不同类型的拓扑跃迁。理解这种梯度非周期系统中的光波的理论基础将与材料和器件的实验表征密切相关。特别是，严格的电磁理论和器件级建模的制造结构将进行。制备样品的光学发射和输运性质将通过稳态和时间分辨荧光光谱结合材料的结构表征进行研究。这项工作为一种新型光子材料铺平了道路，这种材料利用拓扑效应和非周期顺序来操纵活性纳米结构中的光子传输和光定位现象。此外，这项研究可以导致纳米光子学中新的表面现象的发现，并将使开发新的策略来促进非周期系统中的光物质相互作用，这些系统的发射特性本质上由其拓扑不变量的性质决定。

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.