The properties of two-dimensional fractal plasma photonic crystals with Thue-Morse sequence

Abstract

In this paper, the properties of the acceptor modes and photonic band gaps (PBGs) of two-dimensional (2D) fractal plasma photonic crystals (PPCs) under a transverse-magnetic wave are theoretically studied by a modified plane wave expansion method. The density of states is calculated to elaborate the characteristics of the proposed 2D PPCs in which the dielectric cylinders are inserted in the plasma background according to the iteration rule of the Thue-Morse sequence with square lattices. The band structures of the proposed PPCs and 2D PPCs with a conventional square lattice are numerically determined to analyse the properties of PBGs and acceptor modes. The results illustrate that the performance is improved in the proposed PPCs compared to the 2D conventional PPCs with similar lattices. The larger PBGs and higher cutoff frequency are obtained when the Thue-Morse structure is introduced. The lowest edges of PBGs are flat, and they are originated from the Mie resonances. The acceptor modes can be considered as the quasi-localized states since the Thue-Morse sequence has the self-similarity and non-periodicity at the same time. The influences of configurational parameters on the properties of the proposed PPCs are studied in detail as well. The results demonstrate that the PBGs and acceptor modes can be easily tuned by changing those configurational parameters.