Electromagnetic force based on trapped mode of asymmetrical split ring

In this paper, a multi-layered structure based on coupled magnetic/electric resonators is presented. The multi-layered structure can generate a significant electromagnetic force in the terahertz band. The electromagnetic force is calculated by using Maxwell Stress Tensor. The asymmetrical split ring is utilized for field confinement and the multi-layered structure enhances the coupling in the dielectric layer and in the air gap. This leads to a high Q factor and large electromagnetic force. By taking the gravity and the area of the unit cell into consideration, we prove that this force is large enough (about three orders of magnitude higher than in the visible band) to manipulate the unit cell with a small incident power density (<50 nW/μm2).