Photonic band gap in different spatial structures of two-dimensional amorphous photonic materials

Photonic gaps of two-dimensional amorphous photonic materials consisting of different dielectric basic units are simulated by using the multiple scattering method. Even though all of these amorphous photonic materials have only short-range dielectric order, they still possess a photonic band gap. When the basic unit is made of dielectric cylinders, the S-wave gap exists, and when the number of cylinders in the basic units increases, a second gap may open. However, if it is constructed by air holes and a connecting dielectric background, we obtain both the S- and P-wave gaps. The positions and widths of these gaps in amorphous materials are close to the corresponding values in the periodic structure. Our results give further confirmation that shortrange order is one of the major causes of formation of the photonic gap.