Precision Mass and Density Measurement of Individual Optically Levitated Microspheres
Precision Mass and Density Measurement of Individual Optically Levitated Microspheres
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DOI：
10.1103/physrevapplied.12.024037
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发表时间：
2019-02
影响因子：
4.6
通讯作者：
Charles P. Blakemore;Alexander D. Rider;Sandip Roy;A. Fieguth;A. Kawasaki;N. Priel;G. Gratta
中科院分区：
文献类型：
--
作者：
Charles P. Blakemore;Alexander D. Rider;Sandip Roy;A. Fieguth;A. Kawasaki;N. Priel;G. Gratta
我们报道了一种利用静电共悬浮技术对直径约-4.7微米的光学悬浮微球进行的质量测量。捕获的带电微球的质量是通过在已知静电力的影响下，通过保持其轴(垂直)位置与光学反馈力固定来测量的。通过外推到在没有光功率的情况下支撑微球对抗重力所需的静电力，得到了系统不确定度为1.8美元的质量测量结果。在三个案例中，从聚合物涂层硅束上的陷阱中回收微球，并用电子显微镜成像来测量它们的半径。单个微球的质量和半径的同时精确表征意味着密度为$1.55\pm0.08~$g/cm3$。从光学陷阱中回收单个微球的能力为进一步诊断打开了大门。
We report an $\textit{in situ}$ mass measurement of approximately-$4.7{\text -}\mu$m-diameter, optically levitated microspheres with an electrostatic co-levitation technique. The mass of a trapped, charged microsphere is measured by holding its axial (vertical) position fixed with an optical feedback force, under the influence of a known electrostatic force. A mass measurement with $1.8\%$ systematic uncertainty is obtained by extrapolating to the electrostatic force required to support the microsphere against gravity in the absence of optical power. In three cases, the microspheres are recovered from the trap on a polymer-coated silicon beam and imaged with an electron microscope to measure their radii. The simultaneous precision characterization of the mass and radius of individual microspheres implies a density of $1.55\pm0.08~$g/cm$^3$. The ability to recover individual microspheres from an optical trap opens the door to further diagnostics.