Zhao Yiqiong, Shapiro David, McGloin David, Chiu Daniel T, Marchesini Stefano
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 947202, USA.
Opt Express. 2009 Dec 7;17(25):23316-22. doi: 10.1364/OE.17.023316.
It is well known that a circularly polarized Gaussian beam carries spin angular momentum, but not orbital angular momentum. This paper demonstrates that focusing a beam carrying spin angular momentum can induce an orbital angular momentum which we used to drive the orbital motion of a micron-sized metal particle that is trapped off the beam axis. The direction of the orbital motion is controlled by the handedness of the circular polarization. The orbiting dynamics of the trapped particle, which acted as an optical micro-detector, were quantitatively measured and found to be in excellent agreement with the theoretical predictions.
众所周知，圆偏振高斯光束携带自旋角动量，但不携带轨道角动量。本文证明，聚焦携带自旋角动量的光束可以诱导出轨道角动量，我们利用该轨道角动量来驱动微米级金属粒子在离光束轴处被捕获时的轨道运动。轨道运动的方向由圆偏振的旋向控制。作为光学微探测器的捕获粒子的轨道动力学被定量测量，发现与理论预测非常吻合。
