Half-disordered photonic crystal slabs.

Optical transmission spectra of finite-thickness slabs of two-dimensional triangular-lattice photonic crystals of air holes in a dielectric matrix with various concentrations of randomly located vacancies (absent air holes) are studied. We focus on structures in which only one half of the structure-the incidence or transmission side-is disordered. We find vacancy-induced scattering gives rise to a strong difference in the two cases; for light incident on the disordered side, high transmission within the photonic pseudogap at normal incidence is predicted, in strong contrast to the opposite case, where low transmission is predicted throughout the pseudogap, as is observed in the case of an ideal structure with no defects.

Vacancy-induced transmission in three-dimensional photonic crystal slabs.

The transmission spectra of finite-thickness slabs of three-dimensional (3D) diamond-lattice photonic crystals of air spheres in a dielectric background in which various concentrations of randomly located vacancies are present are studied. We find that resonant modes associated with isolated defects couple to form an extended defect band, leading to a significant increase in transmission for frequencies inside the 3D photonic bandgap. Outside the 3D gap, vacancies induce scattering from evanescent to propagating modes, leading to an increase in transmission near the pseudo-gap edges within the gap. The local defect density of states for several concentrations of vacancies is computed; thus, it is shown that the total number of defect states and the range of supported frequencies increase due to increasing vacancy density.