A high-speed optical switch based on transforming the shape of nanomaterial through an interacting magnetic and thermal field

基于通过相互作用的磁场和热场改变纳米材料形状的高速光开关

• 批准号: 1607874
• 负责人: Ramki Kalyanaraman
• 金额: $ 31.49万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607874&HistoricalAwards=false
• 关键词: speed; optical; switch; based; transforming

A high-speed optical switch based on transforming the shape of nanomaterial through an interacting magnetic and thermal field. AbstractThe magnetic field has intrigued many generations of scientists and engineers. One reason is that, once a magnetic field is created it can supply an almost limitless force, such as the Lorentz force, on electrical charges and currents. If this could be exploited then one could have optical, electronic, and data storage technologies that operate on very low power with low energy consumption. Unfortunately, typical magnets, such as a refrigerator magnet, cannot change the optical properties of materials because it applies very weak forces on the charges flowing within the solids and liquids in our familiar environment. This is one reason why nature does not have examples of materials whose optical properties are controllable by magnetic fields. Here the researchers propose to solve this problem by utilizing the fact that when a material melts or freezes, a short lived (few nanoseconds) but extremely large current can be generated at the boundary between the solid and liquid regions. This transient current could be large enough such that, when a refrigerator magnet is brought in its vicinity, the material can be deformed substantially. Thus, physical properties such as the transmission of light can be dramatically changed. They call this effect the MAgneto-THermal or MaTh effect and anticipate the creation of a new type of high-speed optical switching device based on reversibly changing its light transparency. Such devices could find application in optical and quantum computing hardware and in electronic components. Large transient thermal gradients involving a solidification or melting front can be created within nanomaterials by heating by nanosecond pulsed laser light. Preliminary hypothesis suggests that at the boundary of a moving phase front, i.e. solidification or melting front, the mass density difference creates a charge imbalance resulting in a large transient current density. Thermal modeling studies and experiments show that metal nanoparticles in the 10-100 nm size range melted by nanosecond pulses can undergo shape deformation and even break-up in the presence of moderate magnetic fields. Since these shape changes and break-up effects can be reversed by laser thermal dewetting effects, a very fast change in optical properties can be achieved in the presence of a simultaneous magnetic and thermal field. The goal of the research is to design, fabricate, and demonstrate an optical device based on the magnetic field break-up and thermal field re-assembly of metal nanoparticles. The researchers plan to use a combination of thin film deposition, cost-effective nanosphere lithography, etching, pulsed laser melting, and optical characterization. They will investigate the device performance as a function of laser and materials parameters. They anticipate that the proposed tasks will also enhance their fundamental understanding of the coupled magnetic-thermal effect. Therefore, new knowledge as well as a new technology is expected from the planned experimental and theoretical investigations.

一种基于相互作用的磁场和热场来改变纳米材料形状的高速光开关。摘要磁场引起了许多代科学家和工程师的兴趣。其中一个原因是，一旦产生磁场，它就可以为电荷和电流提供几乎无限的力，如洛伦兹力。如果可以利用这一点，那么人们就可以拥有在非常低的功率和低能耗下运行的光学、电子和数据存储技术。不幸的是，典型的磁铁，如冰箱磁铁，不能改变材料的光学性质，因为在我们熟悉的环境中，它对流动在固体和液体中的电荷施加非常微弱的力。这就是为什么自然界没有可由磁场控制光学性质的材料的例子的原因之一。在这里，研究人员建议通过利用这样一个事实来解决这个问题：当材料熔化或冻结时，在固体和液体区域之间的边界上可以产生短暂的(几纳秒)但极大的电流。这种暂态电流可能足够大，以至于当冰箱磁铁被带到它附近时，材料可以实质上变形。因此，可以显著改变诸如光的传输之类的物理属性。他们将这种效应称为磁热效应或数学效应，并预计将基于可逆地改变其光透明度来创造一种新型的高速光开关设备。这种设备可以在光学和量子计算硬件以及电子元件中找到应用。通过纳秒脉冲激光加热，可以在纳米材料内部产生包括凝固或熔化前沿在内的大的瞬时温度梯度。初步假设认为，在运动相前沿的边界，即凝固或熔化前沿，质量密度差产生电荷不平衡，导致较大的暂态电流密度。热模拟研究和实验表明，在中等磁场的作用下，纳秒脉冲熔化10-100 nm尺寸的金属纳米粒子可以发生形状变形甚至碎裂。由于这些形状变化和破裂效应可以被激光热脱湿效应逆转，因此在同时存在磁场和热场的情况下，可以实现光学性质的非常快速的变化。本研究的目标是设计、制造和展示一种基于金属纳米颗粒的磁场分解和热场重组的光学器件。研究人员计划使用薄膜沉积、成本效益高的纳米球光刻、蚀刻、脉冲激光熔化和光学表征的组合。他们将研究激光和材料参数对器件性能的影响。他们预计，拟议的任务还将加强他们对磁热耦合效应的基本理解。因此，有计划的实验和理论研究将带来新的知识和新的技术。