Two-dimensional photonic crystals with insertion of circular and triangular defects

Abstract

In this work, we calculate photonic band structure for a defective two-dimensional photonic crystal using plane wave expansion method and supercell technique. The photonic crystal comprises circular GaAs cylinders arranged in a two-dimensional hexagonal lattice embedded in an air background in which circular and triangular GaAs defects are inserted. Within the photonic band gap, we can observe a defect mode, whose electric field intensity exhibits a bipolar pattern confined around the defect. If we increase pressure while keeping the GaAs dielectric constant at a constant temperature, we observe that the defective modes shift toward higher frequencies without changing the width of the photonic band gap. Moreover, increasing the radius of the circular GaAs defect favors the appearance of a new defective mode within the photonic band gap. However, if we increase the length of the triangular defect, only a single defect mode may be observed at frequencies close to the air band. We hope that these findings can be considered for the development of new photonic devices.