NER: Photoacoustic Characterization of Nanoelectromechanical Systems

在这项提案中，我们将开发高分辨率光声技术来产生和检测纳米级系统中的声振动，并证明该系统在表征双钳位NEMS光束谐振器方面的可行性。目前的NER方案旨在克服光声显微镜中的这些分辨率问题，并展示其在纳米级器件：NEMS中的适用性。为了实现这一目标，我们将开发一种光学近场光声显微镜系统，该系统将允许我们产生并检测NEMS设备中的声和热振动。该系统将使用调制的连续波激光器(最高可达5 GHz)来激励，并将使用连续波探测激光器来分别监测局部位移和温度。利用高折射率固体浸没透镜克服空气中的衍射极限，可以获得高的空间分辨率。基于SIL的技术非常适合于在NEMS设备中产生和检测声波，因为它允许将空气中的激光光斑尺寸减小到衍射极限以下，同时保持高灵敏度干涉检测所需的光学吞吐量。这项拟议的研究工作旨在评估这项实验技术，它将成为一项使能技术，并有助于回答有关通过这些设备的能量流动的基本问题。这一NER努力将允许对NEMS的高分辨率光声显微镜进行初步的可行性研究，并为未来发展近场光学探测器以产生和检测纳米级结构中的声子奠定基础。研究生支持也包括在这一努力中。学生将获得真正的跨学科教育体验，并接受近场光学、声学和纳米力学领域的培训。本期会议将具体讨论以下主题：

In this proposal, we will develop high-resolution photoacoustic techniques for generating and detecting acoustic vibrations in nanoscale systems and demonstrate the feasibility of this system in the characterization of doubly clamped NEMS beam resonators.The current NER proposal seeks to overcome these resolution problems in photoacoustic microscopy and demonstrate its applicability to nanometer scale devices: NEMS. To accomplish this, we will develop an optical near-field photoacoustic microscopy system that will allow us to generate and detect acoustic and thermal vibrations in NEMS devices. This system will have a modulated CW laser (up to 5 GHz) for excitation and a CW probe laser will be used to monitor the local displacement and temperature, respectively. High spatial resolution will be obtained by incorporating a high refractive index solid immersion lens (SIL) to overcome the diffraction limit in air. The SIL based technique is well suited for the generation and detection of acoustic waves in NEMS devices because it allows for reduction of laser spot size below the diffraction limit in air while maintaining the optical throughput necessary for high sensitivityinterferometric detection. The proposed research effort is aimed at evaluating this experimental technique, which will act as an enabling technology and help answer fundamental questions regarding the energy flow through these devices.This NER effort will allow for an initial feasibility study on high-resolution photoacoustic microscopy of NEMS and provide the foundation for future development of near-field optical probes for the generation and detection of acoustic phonons in nanoscale structures. Graduate student support is also included in this effort. The students will have a truly interdisciplinary educational experience and receive training in the areas of near-field optics, acoustics, and nanoscale mechanics. This NER specifically addresses the following themes: