Librational feedback cooling
Librational feedback cooling
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DOI：
10.1103/physreva.106.023503
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发表时间：
2022-08-03
影响因子：
2.9
通讯作者：
Gratta, Giorgio
中科院分区：
文献类型：
--
作者：
Blakemore, Charles P.;Martin, Denzal;Gratta, Giorgio
在光学捕获的二氧化硅微球中，可以观察到刚体围绕优选方向进行角振荡的振动运动。我们演示了在外电场耦合其电偶极矩下诱导旋转的直径类似于5 μ m的球体的1个振动自由度的冷却。冷却是通过在旋转场中加入相位调制来完成的。通过对电场的相位施加pi/2位移并拟合由此产生的振动运动的指数衰减来量化冷却程度，以获得阻尼时间，以及从观察到的平衡振动中估计模态温度。该结果是研究捕获微球动力学的重要一步，对于将机械运动冷却到基态至关重要，同时也提供了微观尺度上材料中电荷迁移率的见解。
Librational motion, whereby a rigid body undergoes angular oscillation around a preferred direction, can be observed in optically trapped, silica microspheres. We demonstrate the cooling of 1 librational degree of freedom for similar to 5-mu m-diameter spheres that have been induced to rotate with an external electric field coupled to their electric dipole moment. Cooling is accomplished by adding a phase modulation to the rotating field. The degree of cooling is quantified by applying a pi/2 shift to the phase of the electric field and fitting the resulting exponential decay of the librational motion to obtain a damping time, as well as estimating a mode temperature from the observed libration in equilibrium. The result is an important step in the study of the dynamics of trapped microspheres, crucial to cooling the mechanical motion to its ground state, as well as providing insights regarding the charge mobility in the material at microscopic scales.