EAGER: Toward Monolithic Optically-Pumped Single-Photon Sources Based on Deterministic InGaN Quantum Dots in GaN Nanowires

单光子源是许多未来量子技术最有用的基本组成部分之一。特别是，量子通信，量子计算和量子传感是高性能单光子源的发展可以彻底改变的领域。为了实现这些实际的量子应用，这样的光子源必须是鲁棒的、相干的、可调谐的和明亮的，并且它们应该同时表现出高的光收集效率和方向性。到目前为止，还没有一种技术可以提供这样一种同时结合所有这些关键特性的量子光源。该项目旨在开发一种能够满足这些激进性能规格的单光子源。这种前所未有的性能将使光子集成电路平台的未来发展成为可能，该平台将同时提高性能和效率，并有助于满足下一代量子光子技术的低尺寸、低重量和低功耗限制。除了高影响力的研究进展，我们的项目还将支持纳米科学和纳米技术的跨学科教育活动。由于拟议的研究项目跨越了科学和工程的不同学科，如光学、材料科学、电气工程、物理和化学，它将导致一系列潜在的、实践的学习活动，可以吸引不同背景的学生。该项目的主要研究目标是通过开发需要生长一维iii -氮化物纳米线（NW）结构的新型光子平台来推进对非经典光源的知识理解。这一进步将使实用量子技术的波长非常适合现有光纤通信基础设施的长距离量子网络。在这个EAGER提案中，我们探索了一种新的和独特的技术，用于通过等离子体辅助分子束外延（PAMBE）自下而上的方法，在内部确定放置InGaN量子点（QDs）的氮(N)极性GaN NWs的生长。与自上而下的技术不同，自下而上的生长方法允许将量子点适当地放置在锥形nw波导的轴线上，并通过减小nw顶部的锥形角度来改进光提取。所提出的研究的长期目标是实现明亮和超光谱纯的单光子源（SPSs），满足积极的性能规格，如高保真纠缠的高计数率和接近零的自相关因子。在这个EAGER项目中执行的工作将作为设计高效和一致的可调SPSs的基础。该项目将促进对NWs中InGaN/GaN量子点的MBE生长以及相关生长条件（包括极性和生长速率控制）的了解。通过研究，我们将更好地了解基于确定性量子点nws的SPSs及其发射特性。该项目还将产生技术进步，通过增加量子点内的铟掺入和控制nw的极性，将nw基器件技术的光发射推向更长的波长。提出的研究将导致对涉及可扩展量子光子器件和集成电路的机制和过程的更深入的基本见解。这种跨学科的研究结合了材料科学、量子物理、化学工程和电气工程，在几个科学领域产生了新的基础知识，表明这个概念是高度新颖和变革的。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。

Single-photon sources are one of most useful basic building blocks for many future quantum technologies. In particular, quantum communication, quantum computing and quantum sensing are the areas that can be revolutionized by the development of high-performance single-photon sources. In order to enable these practical quantum applications, such photon sources must be robust, coherent, tunable and bright, and they should exhibit high- light-collection efficiency and -directionality at the same time. To date, no technology options can provide such a quantum light source that simultaneously combines all of these key properties. This project aims to develop a single-photon source that can meet these aggressive performance specifications. Such unprecedented performance will enable future development of a photonic integrated circuit platform that will simultaneously improve performance and efficiency as well as help meet low size, weight and power-cost constraints for next-generation quantum photonic technologies. In addition to high impact research advancement, our project will also support interdisciplinary education activities in nanoscience and nanotechnology. Because the proposed research project crosses different disciplines of science and engineering, such as optics, materials science, electrical engineering, physics, and chemistry, it will lead to a range of potential, hands-on learning activities that can engage students of varying backgrounds.The primary research objective of the proposed project is to advance intellectual understanding of non-classical light sources through the development of novel photonic platforms that require growth of one-dimensional III-nitride nanowire (NW) structures. This advancement will enable practical quantum technologies at wavelengths ideally suited for long-distance quantum networks with existing fiber-optic telecommunication infrastructures. In this EAGER proposal, we explore a new and unique technique for the growth of nitrogen (N)-polar GaN NWs with InGaN quantum dots (QDs) deterministically placed inside using a bottom-up approach via plasma-assisted molecular beam epitaxy (PAMBE). Unlike a top-down technique, the bottom-up growth method allows proper placement of QDs on the axis of tapered NW-waveguides and an improved light extraction with reduced tapering angles on top of NWs. The long-term objective of the proposed research is to achieve bright and ultra-spectrally pure single-photon sources (SPSs) that meet aggressive performance specifications, such as high count rate and near-zero auto-correlation factors for high-fidelity entanglement. The work performed within this EAGER project will serve as a foundation for designing highly-efficient and coherent tunable SPSs. The project will advance knowledge on the MBE growth of the InGaN/GaN QDs within NWs and the associated growth conditions including polarity and growth rate control. The deterministic QD-NWs based SPSs and its emission properties will be well-understood from the study. This project will also generate technical advancements to push the light emission towards longer wavelengths for the NW-based device technologies by increasing the indium incorporation within QDs and controlling the polarity of NWs. The proposed research will lead to deeper fundamental insights into mechanisms and processes involved in scalable quantum photonic devices and integrated circuits. This inherently interdisciplinary research combines material science, quantum physics, chemical engineering and electrical engineering to generate new fundamental knowledge in several scientific fields, indicating that the concept is highly novel and transformative.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.