基于焦散线理论的表面波激发光栅结构设计

Caustic theory is a method of constructing the initial wavefront by using the tangent clusters of the light propagation trajectories. The surface wave designed and transmitted based on the caustic theory has the advantages of local field enhancement and controllable propagation trajectory, so it has important applications in optical microscopy, optical sensing, and control of light wave coupling. A method for designing the grating structure of Bloch surface wave excitation based on the caustic theory is proposed. Using bilinear grating structure for numerical simulation,a non-diffraction surface wave that can propagate 100 μm is realized, and the influence of the grating structure parameters on the coupling efficiency of the surface wave is analyzed. Furthermore, a simple grating structure is designed according to the caustic theory, which can realize the regulation of self-accelerating transmission of surface waves along any trajectory through simulation calculations. The results provide an effective way to manipulate the transmission of light waves at the sub-wavelength scale and the port design of on-chip optical interconnection.