Collaborative Research: Intentionally Nonlinear Design of High-frequency Atomic Force Microscopy for Enhanced Material Characterization

自20世纪80年代初发展以来，原子力显微镜（AFM）已成为纳米和生物科学领域最有用的成像工具之一。该奖项支持一种新型原子力显微镜的理论和实验研究，这种新型原子力显微镜是通过有意非线性共振的建设性使用实现的，能够利用高频测量进行传感。除了证明在纳米/微设计中有意非线性的建设性利用概念的有效性之外，在更广泛的意义上，该项目的方法可以作为一个测试平台，用于评估将强非线性纳入复杂的机械系统如何导致巨大的性能提升。这项工作可能具有潜在的变革性，因为它可以提供基于高频传感的有意非线性AFM技术的新范例，具有显着提高灵敏度和性能的能力。获得的AFM传感能力将成为纳米和生物科学等领域无与伦比的工具。详细的分析，计算和实验研究将进行一种新的微悬臂梁设计，使高频非线性AFM。在动态模式下，AFM微悬臂梁的两个主要弯曲模式之间有意设计了1:n的内部共振，其中包含一个内硅桨叶，导致桨叶响应中的高频谐波放大，这是AFM提高灵敏度的基础。研究小组将开发显著增强的AFM测量样品材料性能和形貌，通过感应响应中的高谐波来实现。研究团队将通过理论研究系统地研究、优化、扩展和验证这一有前途的概念，以表征桨对不同类型相互作用力的响应，并将进行一系列扩展的实验测试，以评估高阶内部共振设计对拓扑结构和材料特性变化的敏感性。此外，结合多个同步内部共振的多桨AFM设计将进行定量表征分析，而相关的微加工问题也将得到解决。

Since its development in the early 1980s, atomic force microscopy (AFM) has been one of the most useful imaging tools in the fields of nano- and biosciences. This award supports theoretical and experimental studies of a new type of AFM realized through constructive use of intentional nonlinear resonance enabling the utilization of high-frequency measurements for sensing. Apart from proving the efficacy of the concept of constructive utilization of intentional nonlinearity in nano/micro designs to achieve performance not otherwise attainable, in a broader sense this project's approach can act as a testbed for assessing how strong nonlinearity incorporated into a complex mechanical system can lead to drastic performance gains. This work can be potentially transformative, since it can provide a new paradigm of intentionally nonlinear AFM technology based on higher-frequency sensing, with demonstrated capacity for drastically enhanced sensitivity and performance. The gained AFM sensing capability will be an incomparable tool in fields such as nano- and bio-sciences.Detailed analytical, computational and experimental studies will be performed of a new, microcantilever beam design enabling higher-frequency nonlinear AFM. Under dynamic mode operation an intentionally designed 1:n internal resonance between the two leading bending modes of the AFM microcantilever incorporating an inner Silicon paddle, leads to magnification of high-frequency harmonics in the paddle response, which is the basis for AFM of improved sensitivity. The research team will develop the significantly enhanced AFM measurements of sample material properties and topography, achieved through sensing of higher harmonics in the response. The research team will systematically study, optimize, extend and validate this promising concept through theoretical studies to characterize the paddle's response to different types of interaction forces, and will perform an extended series of experimental tests to assess the sensitivity of high-order internal resonance designs to changes in topology and material properties. Moreover, multi-paddle AFM designs incorporating multiple simultaneous internal resonances will be analyzed for quantitative characterization, whereas related microfabrication issues will also be addressed.