Photonic Bandgap Inspection in 2-D Sublattices

Large photonic bandgaps (PBGs) have been obtained by sweeping linearly the parameters of complex sublattices inside the unitary cells of square- and triangular-lattice photonic crystals. An efficient frequency-domain finite-element method with periodical boundary conditions has been used for theoretical analyses. PBGs in silicon/air photonic crystals for both polarization modes have been considered for up to 21 eigenmodes and both low- and high-order PBGs have been obtained by this relatively simple systematic process.