Wu Yi-Jing, Zhuang Jing-Han, Yu Pan-Pan, Liu Yi-Fan, Wang Zi-Qiang, Li Yin-Mei, Qiu Cheng-Wei, Gong Lei
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, China.
Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
Nat Commun. 2025 Jan 11;16(1):593. doi: 10.1038/s41467-024-55781-y.
The spin angular momentum (SAM) plays a significant role in light-matter interactions. It is well known that light carrying SAM can exert optical torques on micro-objects and drive rotations, but 3D rotation around an arbitrary axis remains challenging. Here, we demonstrate full control of the 3D optical torque acting on a trapped microparticle by tailoring the vectorial SAM transfer. To this end, we construct a theoretical relationship between the 3D SAM vector of a tightly focused field and the local polarization helicity of the incident field. In practice, a single-beam configuration is proposed for dynamic 3D SAM manipulation, facilitating time-varying vectorial SAM transfer to particles. Control of 3D optical torque on birefringent microparticles is validated by simulations, and dynamic 3D rotations of optically trapped particles around arbitrary axes are experimentally demonstrated. Our work paves the way for manipulating 3D optical torque and particle spinning, which is expected to boost new functionalities and applications of optical tweezers.
自旋角动量（SAM）在光与物质的相互作用中起着重要作用。众所周知，携带SAM的光可以对微观物体施加光扭矩并驱动其旋转，但围绕任意轴的三维旋转仍然具有挑战性。在此，我们通过定制矢量SAM转移，展示了对作用于捕获的微粒上的三维光扭矩的完全控制。为此，我们构建了一个紧密聚焦场的三维SAM矢量与入射场的局部偏振螺旋度之间的理论关系。在实践中，我们提出了一种单光束配置用于动态三维SAM操纵，便于随时间变化的矢量SAM转移到粒子上。通过模拟验证了对双折射微粒的三维光扭矩控制，并通过实验证明了光学捕获粒子围绕任意轴的动态三维旋转。我们的工作为操纵三维光扭矩和粒子旋转铺平了道路，有望推动光镊的新功能和应用。
