论文标题
使用拓扑保护的单向传输表面弧波进行光学拉动
Optical pulling using topologically protected one-way-transport surface-arc waves
论文作者
论文摘要
本文提出了一种新的方法，通过使用夹在两个手性超血超材料之间的空气指导来实现颗粒的可靠光学拉力。拉力通过在波导的两个超材料表面上支撑的一对单向传输表面弧形之间的模式转换引起的拉力。表面弧形弥合了孤立的散装等频表面（EFSS）之间的动量缝隙，并受到EFSS的非平凡Chern数量的拓扑保护。当粒子散布具有相对较小的波数$ k_ {x1} $的入射表面 - 弧波时，其能量的一部分被转移到其他表面 - arc模式下，$ k_ {x2}（> k_ {x1}）。由于电磁波在此过程中从粒子成比例到$ k_ {x2} -k_ {x1} $的额外的前向动量，因此粒子将始终受到光学拉力拉力，无论其材料，形状和大小如何。由于手性的表面弧波不受局部疾病的反向散射的影响，并且超材料是XY平面中各向同性的，因此可以在弯曲的空气波导中实现强大的光学拉力，并且可以超越标准的光学拉力拉力机制，这些机制仅限于直线拉动。
This paper proposes a new method to achieve robust optical pulling of particles by using an air waveguide sandwiched between two chiral hyperbolic metamaterials. The pulling force is induced by mode conversion between a pair of one-way-transport surface-arc waves supported on the two metamaterial surfaces of the waveguide. The surface arcs bridge the momentum gaps between isolated bulk equifrequency surfaces (EFSs) and are topologically protected by the nontrivial Chern numbers of the EFSs. When an incident surface-arc wave with a relatively small wavenumber $k_{x1}$ is scattered by the particle, a part of its energy is transferred to the other surface-arc mode with $k_{x2}(>k_{x1}). Because the electromagnetic wave acquires an additional forward momentum from the particle proportional to $k_{x2}-k_{x1}$ during this process, the particle will always be subjected to an optical pulling force irrespective of its material, shape and size. Since the chiral surface-arc waves are immune to backscattering from local disorders and the metamaterials are isotropic in the xy plane, robust optical pulling can be achieved in a curved air waveguide and can go beyond standard optical pulling mechanisms which are limited to pull in a straight-line.
