The intensity gradient of light represents the most important property for optical tweezers to manipulate small particles, which is known to produce a conservative optical force that is either attractive or repulsive. Here, it is shown that Kerker interference, the interplay between electric and magnetic dipoles induced in nanoparticles, permits the intensity gradient to exert a nonconservative optical force, in the case of a standard optical trap created with linearly or elliptically polarized Gaussian beams. The Kerker‐type intensity‐gradient force has an “anisotropic” directionality, and it tends to repel particles away from the beam axis. Such repulsive effects can greatly sensitize the particle trapping behavior of optical tweezers to the particle size. Utilizing these peculiar properties, all‐optical sorting of Si nanoparticles is theoretically demonstrated, with tunable size‐selection criterion and accuracy.

中文翻译：

---

光的Kerker型强度梯度力

光的强度梯度代表了光学镊子操纵小颗粒的最重要特性，众所周知，这会产生吸引或排斥的保守光学力。此处显示，在使用线性或椭圆偏振高斯光束创建的标准光阱的情况下，纳米粒子中感应的电偶极子和磁偶极子之间的相互作用，即刻克干涉，允许强度梯度施加非保守的光学力。Kerker型强度梯度力具有“各向异性”的方向性，它趋向于排斥远离光束轴的粒子。这种排斥作用可以极大地使光镊的颗粒捕获行为对颗粒尺寸敏感。利用这些独特的特性，