Imaging the vibrations of nanomechanical resonators means measuring their flexural mode shapes from the dependence of their frequency response on in-plane position. Applied to two-dimensional resonators, this technique provides a wealth of information on the mechanical properties of atomically-thin membranes. We present a simple and robust system to image the vibrations of few layer graphene (FLG) resonators at room temperature and in vacuum with an in-plane displacement precision of ≈0.20 μm. It consists of a sturdy vacuum enclosure mounted on a three-axis micropositioning stage and designed for free space optical measurements of vibrations. The system is equipped with ultraflexible radio frequency transmission lines to electrically actuate resonators. With it we characterize the lowest frequency mode of FLG resonators by measuring its frequency response as a function of position on the membrane and by extracting its effective mass. We use the background noise of the undriven vibrational spectrum to calibrate in-plane displacement. Finally, we measure the first three vibration modes of a resonator whose membrane is partially folded and find that folds locally suppress vibrations.

对纳米机械谐振器的振动进行成像意味着根据它们的频率响应对平面位置的依赖性来测量它们的弯曲模式形状。应用于二维谐振器，该技术提供了大量有关原子级薄膜机械性能的信息。我们提出了一个简单而强大的系统来成像几层石墨烯 (FLG) 谐振器在室温和真空中的振动，面内位移精度为 ≈0.20  μ米。它由安装在三轴微定位平台上的坚固真空外壳组成，专为自由空间光学振动测量而设计。该系统配备了超柔韧的射频传输线，以电驱动谐振器。有了它，我们通过测量 FLG 谐振器的频率响应作为膜上位置的函数并提取其有效质量来表征 FLG 谐振器的最低频率模式。我们使用非驱动振动谱的背景噪声来校准面内位移。最后，我们测量了膜部分折叠的谐振器的前三种振动模式，发现折叠会局部抑制振动。