复原胞超光栅中负透射的鲁棒性

Analysis of negative transmission in metagratings with different complex unit cells

基于多重散射理论,研究了复原胞超光栅在发生负向透射,即透射光与入射光在法线同侧时,复原胞的结构对负向透射效率的影响.复原胞由2个不同半径的介质纳米柱组成,它们沿一条线排列起来构成超光栅.结果表明,要实现完美效率,复原胞超光栅对小柱子的半径及其在复原胞内的位置并没有非常严格的要求.这意味着复原胞结构对负向透射现象具有很好的鲁棒性,制备和实现高效的复原胞介质超光栅非常可行.

Based on multiple scattering theory,the effect of the configuration of complex unit cells on transmissivity in the negative first diffraction order is studied when negative transmission occurs in metagratings with a complex unit cell;that is,when transmitted beams lie on the same side of the normal as incident beams occurs in such metagratings.The complex unit cells are composed of two dielectric nanorods of different radii that constitute a metagrating when they are arranged in a line.Our calculations show that no stringent requirements on the radius of the smaller rods and their position in a complex unit cell are required in order for the negative transmission to be perfectly efficient.This implies that the configuration of complex unit cells is robust to the negative transmission,and hence,that it is easier to construct a high-efficiency dielectric metagrating with a complex unit cell.