Ultrafast Magneto-photonic Materials

这个项目将研究普通光学材料对强光的电场和磁场分量做出响应的非凡方式，这些分量能够协同工作，超越电动力学的传统界限。它将专注于一种名为磁电(M-E)整流的过程，该过程导致组成普通绝缘体的电荷分离，其方式与施加电场导致电容器中的电荷类似电池分离的方式大致相同。这一过程有望以一种新的方式将强烈的阳光直接转化为电能(这不要求光是相干的)，但这里将首次研究其通过利用光洛伦兹力调节光的快速切换来推进光子学领域的潜力。这项研究有望通过提供基于物质与电磁辐射的磁而不是电相互作用的超快光学设备技术来启动磁光子学领域。提议的努力的新奇之处在于，在控制光束以直角入射的情况下，在亚皮秒的时间尺度上打开和关闭携带信号的光束。在直角几何结构中，光通过光进行切换是史无前例的，只需一步就可以实现矩阵式信号处理和相关器，以便在极其紧凑的设计中进行模式识别。这项研究将通过它与量子力学中的角动量和宇称时间对称性等基本主题的联系，探索与自旋物理、能量转换、高速通信和量子计算相关的磁过程。因此，它将促进研究生的高级培训，为促进我们劳动力的多样性提供一条重要途径，并将强调跨学科研究，以使新材料与现代光子学的苛刻目标相匹配。这一努力将达到利用磁光材料和现象的革命性特性的超快器件技术的顶峰。技术描述本实验研究计划将对磁电整流进行系统的研究，以评估其在新的紧凑几何结构中实现光的超快切换的有效性，并测试我们对这一过程的理论理解。在具有大的二阶磁电极化率的非线性介质中，被设计成开启或关闭信号光束传输的新型调制器将受到以相对于第一个90度传播的控制光束。与传统的二阶光子相互作用不同，磁电整流理论上可以在所有介质中发生，但在具有大的非对角线三阶极化率的材料中经历了增强。因此，我们将对两种样品进行比较--电光样品(如KDP同构)和非电光样品(如并五苯)--以验证和理解这种新兴的磁光相互作用如何在比以往任何时候都更广泛的材料类别中刺激光子器件技术。由于它的重点是在无场介质中产生瞬时偶极场，该项目还将利用一种复杂的倾斜波前技术来展示光可以在没有光本身以外的任何外部能源的情况下转换为太赫兹辐射。由于磁电过程是由光洛伦兹力调节的，该项目还将阐明在中等光强下增强相对论动力学的机制，远低于I~1018W/cm2强度的相对论光学的惯常门槛。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。

This project will study the extraordinary way that common optical materials can respond to the electric and magnetic field components of intense light, which are capable of working together to surpass the traditional bounds of electrodynamics. It will focus on a process called magneto-electric (M-E) rectification, which induces a separation of the charges composing ordinary insulators in much the same way that application of an electric field causes a battery-like separation of charges in a capacitor. This process promises to enable the conversion of intense sunlight directly to electrical energy in a novel fashion (that does not require the light to be coherent), but will be investigated here for its potential to advance the field of photonics by mediating fast switching of light with the Lorentz force of light for the first time.This research is expected to launch the field of magneto-photonics by providing ultrafast optical device technology based on magnetic rather than electric interactions of matter with electromagnetic radiation. The novelty of the proposed effort centers on switching a signal-carrying beam on and off on a sub-picosecond timescale with a control beam incident at right angles. Switching of light by light in a right-angle geometry is unprecedented and could lead in a single step to matrix-style signal processing and correlators for pattern recognition in exceptionally compact designs. This research will explore magnetic processes relevant to spin physics, energy conversion, high speed communication and quantum computation through its connections with fundamental topics like angular momentum and parity-time-symmetry in quantum mechanics. It will therefore foster advanced training of graduate students, provide an important pathway for promoting diversity in our workforce, and will emphasize inter-disciplinary research to match up new materials with the demanding objectives of modern photonics. This effort will culminate in ultrafast device technology that exploits the revolutionary properties of magneto-photonic materials and phenomena.Technical DescriptionThis experimental research program will undertake a systematic investigation of magneto-electric rectification to assess its utility for enabling ultrafast switching of light by light in new, compact geometries and to test our theoretical understanding of this process. A novel modulator designed to switch the transmission of a signal beam on or off will be subjected to a control beam propagating at ninety degrees with respect to the first in nonlinear media having large second-order, magneto-electric susceptibilities. Unlike conventional second-order photonic interactions, magneto-electric rectification can theoretically take place in all media, but experiences enhancement in materials with large, off-diagonal, third-order susceptibilities. So samples of two varieties will be compared – ones which are electro-optic (like KDP isomorphs) and ones which are not (like pentacene) – in an effort to verify and understand how this emerging class of magneto-optical interactions could spur photonic device technology in much broader classes of material than ever before. Because of its focus on transient dipole field generation in field-free media, this project will also exploit a sophisticated tilted wavefront technique to show that light can be converted to THz radiation without any external energy source other than the light itself. Since the magneto-electric process is mediated by the Lorentz force of light, this project will also shed light on mechanisms that enhance relativistic dynamics at modest light intensities, far below the customary threshold for relativistic optics at intensities of I~1018 W/cm2.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.