EAGER: Photo-Activated Currents and Magnetization in Au-Nanorings (PACMAN)

该计划的主要目的是证明利用偏振控制激光辐射贵金属纳米环中光激活电流和光致磁化的可行性。本研究的具体目标是：i)将激光系统与微尺度霍尔效应磁强计耦合，ii)从理论上寻找待测试的二维Au纳米环阵列的最佳实验配置，iii)基于理论预测在石英和GaAs晶片上制备第一系列样品，iv)通过对石英支撑的样品的光学表征来演示Au纳米环中旋转极化子的产生，V)在垂直辐射几何结构下，使用左右圆偏振光，用集成的微尺度霍尔效应磁强计测量支撑在砷化镓晶片上的金纳米环的光致磁化强度。智力上的优点：这是一个跨越化学、物理、光学、材料科学、工程和纳米技术之间的传统界限的基础、高风险、高回报的变革性研究项目。这个项目具有变革性，因为一项有价值的基础研究将丰富目前对导电纳米结构中极化子传播的理解，该研究利用具有特定利手的圆偏振辐射在封闭的金属纳米环中产生受控的光致瞬时旋转极化子。这一极具创新性的研究项目为新一代纳米器件铺平了道路，这些纳米器件可以用作光激活的二元可切换纳米磁体、光激活的纳米加速器、光激活的磁性纳米发射器和负折射率的超材料等。这种渴望的高回报方面在于对一种耐人寻味但令人着迷的效应的深刻理解，这种效应可能通过开发和设计用于计算和通信的新型纳米设备、纳米天线和传感器来彻底改变纳米技术领域。这项研究的高风险方面主要在于对一个未经检验的想法进行高影响的尖端研究所涉及的内在不确定性，以及它将带来的多学科实验技术挑战。后者包括将激光系统与微尺度霍尔效应磁强计耦合，在衬底上制备缺陷减少的纳米结构和增加Au纳米环的密度，避免相邻纳米环之间的表面等离子体共振耦合，检测Au纳米环中预期的微小光感电流和磁化强度，以及利用不同的圆偏振辐射来控制磁化的符号。更广泛的影响：该项目包括对两个不同学科(化学和物理)的研究生进行跨学科培训，涉及的领域包括化学、物理、光学、材料科学、工程和纳米技术。美国和台湾这一亚洲发展中国家之间的紧密合作将有助于培养新一代博士，使他们具有全球意识。结果将通过在同行评议的期刊上发表和会议发言来公布。

The main goal of this program is to prove the feasibility of photo-activating currents and photo-inducing magnetization in noble metal-nanorings using polarization controlled laser radiation.The specific objectives of this investigation are: i) To couple the laser system with a microscale Hall-effect magnetometer, ii) To find, theoretically, optimum experimental configurations of two-dimensional Au-nanorings arrays to be tested, iii) To fabricate the first series of samples on quartz and GaAs wafers based on the theoretical predictions, iv) To demonstrate the generation of rotating polaritons in Au-Nanorings through the optical characterization of samples supported on quartz, v) To measure photo-induced magnetization in Au-nanorings supported on GaAs-wafers with the integrated microscale Hall-Effect magnetometer under perpendicular radiation geometry, using left and right circularly polarized light.Intellectual Merit: This EAGER is a fundamental, high-risk, high-reward transformative research project that crosses traditional boundaries between chemistry, physics, optics, material sciences, engineering and nanotechnology.? This project is transformative in that the current understanding of polariton propagation in conductive nanostructures will be enriched by a valuable fundamental study of the generation of controlled photo-induced transient rotating polaritons in closed metal nanorings using circularly polarized radiation with specific handedness. This exceptionally innovative research project offers the potential to pave the road of a new generation of nanodevices that could be used as photo-activated binary switchable nanomagnets, photo-activated nano-accelerators, photo-activated magnetic nano-transmitters, and meta-materials for negative refractive index, among others.? The high-reward aspect of this EAGER resides in the deep understanding of an intriguing but fascinating effect that could revolutionize the field of nanotechnology through the development and design of novel nanodevices for computing and communication, nanoantennas and sensors.? The high-risk facet of this study resides mainly on the intrinsic uncertainty involved in a high-impact, cutting edge research on an untested idea and, on the multidisciplinary experimental technical challenges that it will present. The latter include to couple a laser system with a microscale Hall-Effect magnetometer, to fabricate nanostructures with reduced defects and increase the density of Au-nanorings on the substrates avoiding surface Plasmon resonance coupling between neighbor nanorings, to detect the anticipated small photo-induced currents and magnetization in Au-nanorings and, to gain control on the sign of the magnetization using different handedness of circularly polarized radiation. Broader Impact: This project includes the interdisciplinary training of two graduate students of two different disciplines (chemistry and physics) in a field that combines chemistry, physics, optics, material sciences, engineering and nanotechnology. The strong collaboration between USA and Taiwan, an Asian developing nation, will contribute to the preparation of the new generation of PhDs by providing them with global awareness. Results will be diseminated through publications in peer-reviewed journals and conference presentations.