Sub-femto-Newton sensing torsion pendulum for detecting of light force

Posted on 21.09.2022 - 20:54
Mechanical oscillators is widely used in many fields of physics including ultra-high precision measurements, gravity experiments and Optical mechanical systems. A sub-gram-scale silicon wafer is suspended by a tungsten wire with a diameter of 8 microns , forming a torsion pendulum to detect the laser radiation pressure. We demonstrate the application of a low-frequency, highly sensitive torsion pendulum for the measurement of light forces. In the feedback cooling state , the system exhibits a force sensitivity at the end of the pendulum close to 0.1 fN, approaches the thermal noise limit, reaches the detection level of the laser radiation pressure of 60 nanowatts.


Guan, Shengguo; Sun, Jing; Huang, Biao; Cheng, Yanbei; duan, zhenglu; Le, Jianxin (2022): Sub-femto-Newton sensing torsion pendulum for detecting of light force. Optica Publishing Group. Collection.
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Shengguo Guan
Jing Sun
Biao Huang
Yanbei Cheng
zhenglu duan
Jianxin Le


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