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

一种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。磁场引起了许多代科学家和工程师的兴趣。一个原因是，一旦磁场产生，它就可以对电荷和电流提供几乎无限的力，例如洛伦兹力。如果可以利用这一点，那么人们可以拥有以低能耗运行在非常低的功率上的光学、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，因为它对我们熟悉的环境中固体和液体内流动的电荷施加非常弱的力。这就是为什么自然界没有材料的例子，其光学性质是由磁场控制的原因之一。在这里，研究人员建议通过利用以下事实来解决这个问题：当材料熔化或冻结时，可以在固体和液体区域之间的边界处产生短暂（几纳秒）但非常大的电流。该瞬态电流可以足够大，使得当制冷机磁体被带到其附近时，材料可以显著变形。因此，物理性质，如光的透射率可以显着改变。他们称这种效应为MAgneto-THermal或MaTh效应，并预计将创造一种基于可逆改变其透光性的新型高速光开关器件。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，可以在纳米材料内产生涉及固化或熔化前沿的大的瞬态热梯度。初步假设表明，在移动相前沿的边界处，即凝固或熔化前沿，质量密度差产生电荷不平衡，从而导致大的瞬态电流密度。热模拟研究和实验表明，纳秒脉冲熔化的10 - 100 nm尺寸范围内的金属纳米颗粒可以在中等磁场的存在下发生形状变形，甚至破碎。由于这些形状变化和破碎效应可以通过激光热去湿效应逆转，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。本研究的目的是设计、制作并演示一种基于金属纳米粒子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。他们将研究作为激光和材料参数的函数的器件性能。他们预计，拟议的任务也将提高他们对耦合磁热效应的基本理解。因此，新的知识以及新的技术，预计从计划的实验和理论研究。

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.