Ultraslow-light effects in symmetric and asymmetric waveguide structures with moon-like scatterers

• DOI: 10.1007/s11467-016-0598-x
• Publication Date: 2016-10-11T08:16:21Z
• Authors: Yong Wan; Xiao-Hui Ge; Sheng Xu; Yue Guo; Feng Yuan
• Keywords: Saddle; Group velocity; Saddle point; Lattice (music); Slow Light

Ultraslow-light effects in two-dimensional hexagonal-lattice coupled waveguide with moon-like scatterers were theoretically studied using the plane-wave expansion method. For symmetric structures, simulations showed that slow light with high group index can be achieved by shifting the scatterers and adjusting the radius of moon-like scatterers. The maximum group index was over 8:0 × 104. For asymmetric structures, simulations showed that slow light with flat band and high group index can be obtained by shifting the scatterers, adjusting the radius of moon-like scatterers, and rotating the scatterers. The maximum group index was over 5:7 × 105 with a “saddle-like” relationship between the frequency and group index.