Attonewton-meter torque sensing with a macroscopic optomechanical torsion pendulum
Attonewton-meter torque sensing with a macroscopic optomechanical torsion pendulum
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DOI：
10.1103/physreva.101.011802
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发表时间：
2020-01-17
影响因子：
2.9
通讯作者：
Ando, Masaki
中科院分区：
文献类型：
--
作者：
Komori, Kentaro;Enomoto, Yutaro;Ando, Masaki
通过将振荡器耦合到光学腔，可以执行对机械振荡器的位移和作用在其上的力的精确测量。布朗热力是测量灵敏度的一个基本限制，它阻碍了将精确的力测量作为基本研究工具的能力，特别是在宏观量子测量和桌面引力实验的背景下。一个具有低机械共振频率的扭摆，在高于共振频率时，可以受到来自其悬挂的非常小的热力的限制。在这里，我们报告扭矩传感的10毫克扭摆杆镜形成的，使用两个光学腔的任何一个边缘。通过从腔中减去两个信号来测量旋转模式，而腔内辐射压力用于用1 kHz光学弹簧捕获扭转模式。由此产生的扭矩灵敏度为20 aN m/root Hz，是毫克级扭转振荡器的记录。这使我们能够测试自发波函数崩溃的参数制度，福尔斯之间的测试空间为基础的实验，和高频低温超导杠杆。
Precise measurements of the displacement of, and force acting on, a mechanical oscillator can be performed by coupling the oscillator to an optical cavity. Brownian thermal forces represent a fundamental limit to measurement sensitivity which impedes the ability to use precise force measurements as a tool of fundamental enquiry, particularly in the context of macroscopic quantum measurements and tabletop gravitational experiments. A torsion pendulum with a low mechanical resonant frequency can be limited by very small thermal forces-from its suspensions-at frequencies above resonance. Here, we report torque sensing of a 10-mg torsion pendulum formed by a bar mirror, using two optical cavities on either edge. The rotational mode was measured by subtracting the two signals from the cavities, while intracavity radiation pressure forces were used to trap the torsional mode with a 1 kHz optical spring. The resulting torque sensitivity of 20 aN m/root Hz is a record for a milligram-scale torsional oscillator. This allows us to test spontaneous wave-function collapse in a parameter regime that falls in between that tested by space-based experiments, and high-frequency cryogenic cantilevers.