S.E. Dissanayake, K A I L Wijewardena Gamalath, Point Defects in GaAs Photonic Crystals, ILCPA Volume 43, International Letters of Chemistry, Physics and Astronomy (Volume 43)
    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.
    Band Structure, Defect Mode, GaAs, Mode Field Distribution, Multilayer, Photonic Crystal, Plane Wave Expansion, Square Lattice, Supercell