Band gap studies of triangular 2D photonic crystals with varying pore roundness

Photonic crystals (PCs) are theoretically studied in order to correlate the structural parameters with the resulting electromagnetic behaviour. Two-dimensional (2D) PCs of dielectric media are routinely assumed to be formed by circular rods or pores, respectively. Main topics of the paper are band gap modifications (TM- and TE-polarization) for pores of deteriorating roundness, approximated by ellipses of varying eccentricity. On the basis of Maxwell's equations and a 'plane wave expansion', band structures are computed for triangular 2D lattices of air columns in silicon. The results are compared with calculations for circular air columns of varying filling factors. (C) 2000 Elsevier Science Ltd. All rights reserved.