S.E. Dissanayake, K A I L Wijewardena Gamalath, Point Defects in GaAs Photonic Crystals, Volume 43, International Letters of Chemistry, Physics and Astronomy (Volume 43)
https://www.scipress.com/ILCPA.43.91
Abstract:
    Applying plane wave expansion method to one dimensional multilayer system formed from alternating layers of GaAs and air, a defect mode was artificially introduced by removing a GaAs layer at the centre of a supercell and the band structures and mode field distributions were obtained. The defect mode normalized frequency was 0.28. The parameters for developing a Febry-Perot filter in the visible frequencies are given. The point defects in a two dimensional square lattice formed from GaAs rods of radius 0.16<i>a</i> in air was created by removing one GaAs rod at the centre of a supercell and also by increasing the centre GaAs rod radius to 0.5<i>a</i>. The removal of the rod folded the band structure 25 times creating a localized evanescent defect mode. The increment of the centre GaAs rod radius led to five defect bands inside the band gap with one degenerate state creating a monopole, two quadrupoles and two hexapoles. Evolution of the defect modes with the variation of the radius of GaAs rod is also presented.
Keywords:
    Band Structure, Defect Mode, GaAs, Mode Field Distribution, Multilayer, Photonic Crystal, Plane Wave Expansion, Square Lattice, Supercell