We have investigated numerically the photonic bandgap (PBG) and spectral properties of two-dimensional (2-D) square structures fabricated by holographic lithography. Based on the block-iterative frequency-domain method and on the nonorthogonal finite-difference time-domain method, we have calculated band structure as a function of intensity threshold and shown that the PBG of 2-D titania arrays opens only for TM polarization and that directional PBGs can be obtained simultaneously for TE- and TM-polarized waves. In addition, we have shown that symmetry reduction of the atom introduced by holographic lithography can lift the band degeneracies and create an absolute PBG for a square lattice of dielectric rods in air.
© 2004 Optical Society of America
(220.4000) Optical design and fabrication : Microstructure fabrication
(260.2110) Physical optics : Electromagnetic optics
(260.3160) Physical optics : Interference
(350.3950) Other areas of optics : Micro-optics
X. L. Yang, L. Z. Cai, Q. Liu, and Hua-Kuang Liu, "Theoretical bandgap modeling of two-dimensional square photonic crystals fabricated by the interference of three noncoplanar laser beams," J. Opt. Soc. Am. B 21, 1699-1702 (2004)