Liu Lulu, Kheifets Simon, Ginis Vincent, Capasso Federico
School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, USA.
Applied Physics, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium.
Phys Rev Lett. 2016 Jun 3;116(22):228001. doi: 10.1103/PhysRevLett.116.228001.
We demonstrate thermally limited force spectroscopy using a probe formed by a dielectric microsphere optically trapped in water near a dielectric surface. We achieve force resolution below 1 fN in 100 s, corresponding to a 2 Å rms displacement of the probe. Our measurement combines a calibrated evanescent wave particle tracking technique and a lock-in detection method. We demonstrate the accuracy of our method by measurement of the height-dependent force exerted on the probe by an evanescent wave, the results of which are in agreement with Mie theory calculations.
我们展示了一种热限力谱技术，该技术使用由光学捕获在靠近电介质表面的水中的电介质微球形成的探针。我们在100秒内实现了低于1飞牛的力分辨率，这对应于探针2埃的均方根位移。我们的测量结合了校准的倏逝波粒子跟踪技术和锁相检测方法。我们通过测量倏逝波对探针施加的与高度相关的力来证明我们方法的准确性，其结果与米氏理论计算结果一致。
