Precision measurement of optical force based on torsion balance

As an important means of contactless manipulation of targets, optical force has significant application prospects in areas such as light sail propulsion and orbital intervention of space debris. Precise measurement of the optical force generated by spatial targets in complex optical fields is crucial for establishing their spatial dynamics model. The torsion balance can be used to measure the optical torque. We use a 5 μm tungsten fiber to build a torsion balance system to measure the extremely weak optical torque less than 1×10⁻¹⁵ Nm, which can help to establish an accurate model of the interaction between objects and optical forces. At the same time, it provides experimental data for the study of spacecraft orbit control and light sail navigation.