The effect of defect layer on transmissivity and light field   distribution in general function photonic crystals
  We have theoretically investigated a general function photonic crystals (GFPCs) with defect layer, and choose the line refractive index function for two mediums $A$ and $B$, and analyze the effect of defect layer's position, refractive indexes and period numbers on the transmission intensity and the electric field distribution. We obtain some new characters that are different from the conventional PCs, which should be helpful in the design of photonic crystals. 
Xiang-Yao Wu, Si-Qi Zhang, Bo-Jun Zhang, Xiao-Jing Liu, Jing Wang,   Hong Li, Nuo Ba and Xin-Guo Yin
physics.optics