Opt Lett. 2018 Oct 15;43(20):4961-4964. doi: 10.1364/OL.43.004961.
In terms of the law of momentum conservation, the optical pulling force (OPF) is a counterintuitive phenomenon for optical manipulation. We investigate analytically and numerically the tunable OPF exerted on the low refractive index nanoparticle (NP) in a hybrid dimer system when it is illuminated by a plane wave based on the coupled dipole approximation method and the finite-difference time-domain method, respectively. The underlying physical mechanism relies on the near-field electromagnetic coupling between the low refractive index dielectric NP and the plasmonic NP. We further evaluate the dependence of the OPF on the geometrical parameters of the system. It is also numerically demonstrated that a Gaussian beam can be used to achieve pure OPF with no transverse force component. The proposed OPF offers an additional degree of freedom for optical sorting, transport, and trapping of NPs.
从动量守恒定律的角度来看，光拉力（OPF）是一种对光操控来说违反直觉的现象。我们分别基于偶极子耦合近似方法和时域有限差分方法，对平面波照射下混合二聚体系统中低折射率纳米粒子（NP）上的可调 OPF 进行了分析和数值研究。其潜在物理机制依赖于低折射率介电 NP 和等离子体 NP 之间的近场电磁耦合。我们进一步评估了 OPF 对系统几何参数的依赖性。数值结果还表明，高斯光束可用于实现无横向力分量的纯 OPF。所提出的 OPF 为 NPs 的光学分选、传输和捕获提供了额外的自由度。
