Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.
Opt Lett. 2010 Jun 1;35(11):1792-4. doi: 10.1364/OL.35.001792.
We describe a simple approach to detect small mechanical displacements by scattering evanescent optical waves confined around an optical waveguide. Our experimental setup consists of a microcantilever brought into the proximity of a tapered optical fiber. The scattering of evanescent waves and hence the optical transmission through the tapered fiber is strongly dependent on the separation between the fiber and the microcantilever, allowing for sensitive detection of the small oscillations of the microcantilever. Our approach does not require a coherent laser source, yet it provides a displacement sensitivity of ~260fmHz(-1/2) at a small power level of 38microW. It is suitable for scanning probe microscopy and could eventually be adapted to nanomechanical resonators.
我们描述了一种通过散射限制在光波导周围的倏逝光波来检测微小机械位移的简单方法。我们的实验装置由一个微悬臂梁置于锥形光纤附近组成。倏逝波的散射，从而通过锥形光纤的光传输强烈依赖于光纤和微悬臂梁之间的分离，允许对微悬臂梁的小振动进行灵敏检测。我们的方法不需要相干激光源，但它在 38μW 的小功率水平下提供了约 260fmHz(-1/2)的位移灵敏度。它适用于扫描探针显微镜，并且最终可以适应纳米机械谐振器。
