Angular trapping of a linear-cavity mirror with an optical torsional spring
Angular trapping of a linear-cavity mirror with an optical torsional spring
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DOI：
10.1103/physreva.106.013514
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发表时间：
2021-10
影响因子：
2.9
通讯作者：
T. Kawasaki;K. Komori;Hiroki Fujimoto;Y. Michimura;M. Ando
中科院分区：
文献类型：
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作者：
T. Kawasaki;K. Komori;Hiroki Fujimoto;Y. Michimura;M. Ando
光学力学系统在各种物理实验中引起了广泛的关注。在光学机械系统中，利用光学干涉法可以精确测量机械振子的位移或作用力。悬挂镜作为一种机械振荡器，常用于毫克以上的光学机械系统中。然而，由于光辐射压力，线性腔中的微小悬浮镜的偏航转动自由度可能是不稳定的。这种不稳定性限制了腔中积累的光功率，并对灵敏度施加了限制。在此，我们证明了当腔的g因子为负且一个反射镜比另一个反射镜重得多时，可以利用光辐射压力来捕获悬挂反射镜的旋转运动，而不需要额外的主动反馈控制。此外，我们还从实验上证明了捕获的有效性。测量了不同腔内功率的悬挂式微镜的转动强度(ff)。结果表明，激光在腔内的辐射压力实际上是一个正恢复力矩。此外，我们还讨论了用我们的实验装置观测量子辐射压强fl的可行性，作为我们的俘获组态的应用。
Optomechanical systems have attracted intensive attention in various physical experiments. With an optomechanical system, the displacement of or the force acting on a mechanical oscillator can be precisely measured by utilizing optical interferometry. As a mechanical oscillator, a suspended mirror is often used in over a milligram scale optomechanical systems. However, the tiny suspended mirror in a linear cavity can be unstable in its yaw rotational degree of freedom due to optical radiation pressure. This instability curbs the optical power that the cavity can accumulate in it, and imposes a limitation on the sensitivity. Here, we show that the optical radiation pressure can be used to trap the rotational motion of the suspended mirror without additional active feedback control when the g factors of the cavity are negative and one mirror is much heavier than the other one. Furthermore, we demonstrate experimentally the validity of the trapping. We measured the rotational stiffness of a suspended tiny mirror with various intracavity power. The result indicates that the radiation pressure of the laser beam inside the cavity actually works as a positive restoring torque. Moreover, we discuss the feasibility of observing quantum radiation pressure fluctuation with our experimental setup as an application of our trapping configuration.