针对金属表面等离激元光镊热损耗问题, 设计了一种硅基双纳米柱加纳米环的光镊结构.通过有限元仿真在1 064 nm入射光场下计算了三种不同硅基纳米结构(硅基纳米球、纳米柱、纳米环)的场增强效果.利用硅基纳米结构光学共振机理, 设计了一种电场增强倍数达到7.39倍的硅基双纳米柱光镊结构.在此基础上, 增加纳米环使光镊结构的环中心与双纳米柱间隙产生光学共振耦合现象, 得到的电场增强倍数高达11.9倍, 形成了稳定的光学势阱.最后采用麦克斯韦应力张量法对硅基光镊中不同直径的聚苯乙烯小球进行了捕获分析, 并在x、y、z方向上计算分析了直径为25 nm的聚苯乙烯小球在不同位置的捕获力、捕获势能以及捕获刚度.设计的硅基纳米双圆柱加纳米环的光镊结构能够对聚苯乙烯小球起到良好的捕获效果.

To solve the heat loss of the surface plasmon optical tweezers, an optical tweezers of siliconbased doublenanocylinder with nanoring is designed. The field enhancement effects of three different siliconbased nanostructures (siliconbased nanosphere, nanocylinder and nanoring) were calculated by finite element simulation at 1 064 nm incident light field. Then, according to the optical resonance mechanism of siliconbased nanostructures, a siliconbased doublenanocylinder optical tweezers with an electric field enhancement factor of 7.39 times is designed. On this basis, optical resonance coupling is generated between the center of the ring and the gap between the double nanocolumn of the optical tweezers by introducing nanoring to the optical tweezers, which makes the electric field enhancement factor reaches up to 11.9 times and forms a stable optical potential well. Finally, Maxwell's stress tensor method was used to capture and analyze polystyrene beads of different diameters in siliconbased optical tweezers. And the trapping force, trapping potential and capture stiffness of polystyrene spheres with a diameter of 25 nm at different positions were calculated and analyzed in the x, y and z directions. The designed optical tweezers of siliconbased nanocylindrical and nanorings can achieve good results for the capture of polystyrene spheres.