Optical manipulation of metallic microparticles remains a significant challenge because of the strong scattering forces arising from the high extinction coefficient of the particles. This paper reports a new mechanism for stable confinement of metallic microparticles using a tightly focused linearly polarized Gaussian beam. Theoretical and experimental results demonstrate that metallic microparticles can be captured off the optical axis in such a beam. Meanwhile, the three-dimensionally confined particles are observed spinning transversely as a response to the asymmetric force field. The off-axis levitation and transverse spinning of metallic microparticles may provide a new way for effective manipulation of metallic microparticles.

中文翻译：

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金属微粒的离轴光学悬浮和横向旋转

由于粒子的高消光系数产生的强散射力，金属微粒的光学操作仍然是一个重大挑战。本文报告了一种使用紧密聚焦的线性偏振高斯光束稳定限制金属微粒的新机制。理论和实验结果表明，金属微粒可以在这种光束中被捕获在光轴之外。同时，观察到三维受限粒子横向旋转作为对不对称力场的响应。金属微粒的离轴悬浮和横向旋转可能为有效操纵金属微粒提供新的途径。