Quantum plasmonics with extreme nonlinearities for on-chip supercontinuum generation

非线性光学是近几十年来发展迅速的科学领域，在光学信息处理、通信等领域有着重要的应用前景。由于大多数材料的非线性系数通常较低，因此探索具有更高非线性响应的新材料一直是该领域最大的挑战之一。作为一个独特的研究领域，等离子体已经成为一种在纳米尺度上操纵光的新方法。纳米制造的最新进展使等离子体结构在纳米尺度上实现，由于量子尺寸效应导致异常高的非线性响应。本项目旨在将量子等离子体学领域与非线性光学相结合，发现具有极高非线性响应的新型光学材料，并将这种新材料应用于片上超连续统的产生，并且具有超小的占地面积。本项目涉及基础科学探索、纳米材料设计与制造、片上超连续介质产生器件设计与制造以及光学表征。这项研究将解决纳米等离子体学和非线性光学截面的基本问题，并在纳米材料设计和生长、光学表征、器件制造、纳米科学和纳米技术等重要领域培养研究生和本科生。变革的目标是为基于具有极高非线性的工程纳米材料的下一代集成光学元件提供科学基础。以研究为基础的课程发展、研究成果的网上传播、期刊出版物和会议/工作坊报告，将影响更多的学生，包括大学预科学生。技术描述。该项目提出了在量子工程系统中创建强非线性响应的新方法，以及如何使用它来构建超紧凑的超连续统生成装置。本文将系统地研究金属量子阱的非线性光学性质。为了准确地描述和预测金属量子阱系统的非线性响应，将建立一个动态量子静电模型。最先进的量子等离子体薄膜的特征尺寸将降至1-3纳米。根据我们的理论估计和初步实验结果，量子等离子体系统将导致创纪录的高三阶非线性磁化率。所提出的基于量子等离子体波导的超连续介质产生装置，如果成功演示，将是第一个具有微米足迹的超连续介质光源，为高密度集成和片上应用提供了新的机会。除了提出具体的个人概念和设备外，PI还将该项目设想为非线性材料构建和实施方式的范式转变。由于超薄金属薄膜中的大跃迁矩阵元素和高电子密度，量子等离子体结构可以在所需的工作频率下具有极高的非线性响应。该研究成果将填补等离子体动力学和非线性光学领域的知识空白，并为新一代强非线性材料在集成非线性光学中的重要应用铺平道路。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。

Nonlinear optics has been a rapidly growing scientific field in recent decades and holds promise for critical applications in optical information processing, telecommunications, and etc. Because the nonlinear coefficients for most materials are typically low, exploring new materials with higher nonlinear responses has always been one of the greatest challenges in this field. As a distinct research field, plasmonics has emerged as a novel approach to manipulate light at nanoscales. Recent advances in nanofabrication enable plasmonic structures at nanometer scales, leading to exceptionally high nonlinear responses due to the quantum size effect. This project aims to combine the field of quantum plasmonics with nonlinear optics to discover new optical materials with extremely high nonlinear responses and to apply such new materials for on-chip supercontinuum generation with an ultra-small footprint. This project involves fundamental science exploration, nano-material design and fabrications, on-chip supercontinuum generation device design and fabrication, and optical characterizations. This research will address fundamental issues at the cross-section of nanoplasmonics and nonlinear optics, and train graduate and undergraduate students in important areas of nanomaterials design and growth, optical characterization, device fabrication, nano-science, and nanotechnology. The transformative goal is to provide the scientific underpinnings of next generation integrated optical components based on engineered nanomaterials with extremely high nonlinearities. Research-based curriculum development, web-based dissemination of research results, journal publications and conference/workshop presentations, will impact more students including those at the pre-college level. Technical description. This project addresses a new way to create strong nonlinear responses in a quantum engineered system and how to use it to build an ultra-compact supercontinuum generation device. The nonlinear optical properties of metal quantum wells will be systematically investigated. A dynamic quantum electrostatic model will be developed to accurately describe and predict the nonlinear responses of the metal quantum well systems. The state-of-the-art quantum plasmonic films will be fabricated at feature size down to 1-3 nm. Based on our theoretical estimation and preliminary experimental results, the quantum plasmonic systems will lead to the record high third order nonlinear susceptibility. The proposed quantum plasmonic waveguide-based supercontinuum generation devices, if successfully demonstrated, would be the first supercontinuum light source with micrometer footprint, enabling new opportunities for high-density integration and on-chip applications. Other than proposing specific individual concept and device, the PI envisions this project as a paradigm shift in the way a nonlinear material is constructed and implemented. Due to the large transition matrix elements and the high electron density in ultrathin metal films, quantum plasmonic structures can be tailored to possess extremely high nonlinear responses at desired operation frequencies. The outcome of this research will fill up knowledge void in both fields of plasmonics and nonlinear optics and pave the way to a new generation of strong nonlinear materials that may find important applications in integrated nonlinear optics.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.