CAREER: Breaking and engineering reciprocity in magnetless THz and IR devices using 2D materials

电磁波的传播使现代技术和通信系统成为可能。在许多实际应用中，要求这些波在源和观测点互换时能够表现出不同响应的非互易通道/装置中传播。这就是保护信号源和天线免受高功率反射影响的隔离器，能够将信号分配到不同输出的环行器，或者控制光偏振的法拉第旋转器。这些组件是电信、国防、医疗保健和航天工业的基本构件。不幸的是，打破互易性通常需要体积庞大、价格昂贵的磁性材料，而这些材料与集成电路不兼容。该项目提出了一种新的方法，通过利用二维材料的激发特性来打破和设计微/纳米尺度的互易性，而不需要外部磁场。这些发现将被应用于开发低成本、紧凑和高效的非互惠平台，这些平台能够实现新的功能，并与集成电路和其他光电组件兼容。主要目标是为非互易器件建立一个新的范例，减少对磁性材料的依赖，并利用不寻常的反应来重塑未来技术的许多领域。教育和外展工作的重点将是让从K-12到大学的拉美裔学生参与科学、技术、工程和数学领域的学习。暑期奖学金将促进本科生西班牙裔学生参与关于非互易天线的研究项目，允许研究生、本科生和高中生互动，并分享通过在不同频率实施类似概念所学到的知识和经验。组织一次关于互惠的讲习班将使该领域的顶尖专家与研究生和西班牙裔本科生和高中生汇聚一堂，使技术讨论成为可能，并扩大这一令人兴奋的主题对整个社会的影响。这个项目结合并利用二维材料的独特性质，在没有偏磁的情况下打破和操纵时间反转对称。首先，非互易响应将通过用圆偏振光泵浦承受均匀应变的二维材料来实现，远远超过目前使用磁光效应所能获得的响应。该平台将允许研究许多系统在有效偏磁下的响应，远大于在普通实验室中获得的响应，并将使应变工程的实际发展成为可能。这种响应将应用于实现法拉第旋转器和非互易双曲线/相剖面亚曲面，从而实现单向巨大光学力和非互易光束操纵/透镜等功能。其次，将利用二维材料的超快场效应在空间和时间上明智地调制它们的电学性质。在电信行业中，时空调制将被应用于实现低损耗、高效和集成的非互易光子和等离子体平台，能够提高频谱效率和数据速率。该项目中提出的技术是低成本的，与集成电路兼容，旨在显著推进当前非互惠领域的前沿。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The propagation of electromagnetic waves has enabled modern technology and communication systems. In many practical applications, it is required that these waves propagate through nonreciprocal channels/devices able to exhibit different responses when source and observation points are interchanged. This is the case of isolators that protect sources and antennas from high-power reflections, circulators able to distribute signals to different outputs, or Faraday rotators that control the polarization of light. These components are fundamental building blocks for telecommunications, defense, health care, and space industries. Unfortunately, breaking reciprocity usually requires bulky and costly magnetic materials that are not compatible with integrated circuits. This project proposes novel approaches to break and engineer reciprocity at the micro/nano-scale by exploiting exciting properties of two-dimensional materials without requiring external magnetic fields. The findings will be applied to develop low-cost, compact, and highly-efficient nonreciprocal platforms that enable novel functionalities and are compatible with integrated circuits and other optoelectronic components. The main goal is to establish a new paradigm for nonreciprocal devices, lessening the dependence on magnetic materials and exploiting unusual responses to reshape many areas of the coming technology. The educational and outreach efforts will focus on engaging Hispanic students, ranging from K-12 to college, in science, technology, engineering and math. Summer fellowships will foster the participation of undergraduate Hispanic students in a research project about nonreciprocal antennas, allowing graduate, undergraduate, and high school students to interact and share knowledge and experiences learnt by implementing similar concepts at different frequencies. The organization of a workshop about reciprocity will bring together top experts in the field with graduate and Hispanic undergraduate and high-school students, enabling technical discussions and broadening the impact of this exciting topic on all society. This project combines and exploits unique properties of two-dimensional materials to break and manipulate time-reversal symmetry in the absence of magnetic bias. First, nonreciprocal responses far beyond what is currently attainable using magneto-optics effects will be realized by pumping two-dimensional materials subjected to uniform strain with circularly-polarized light. This platform will permit to investigate the response of many systems under effective magnetic bias much larger than those attained in common laboratories and will enable the practical development of strain engineering. Such responses will be applied to realize Faraday rotators and nonreciprocal hyperbolic/phase profile metasurfaces, enabling functionalities such as one way giant optical forces and nonreciprocal beam steering/lensing. Second, the ultrafast field effect of two-dimensional materials will be exploited to judiciously modulate in space and time their electric properties. Spatiotemporal modulations will be applied to realize low-loss, efficient, and integrated nonreciprocal photonic and plasmonic platforms able to enhance the spectrum efficiency and data-rate in the telecommunication industry. The technology proposed in this project is low-cost, compatible with integrated circuits, and aims to significantly advance the current frontiers in the field of nonreciprocity.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.