Birefringence dispersion in Solc-type anisotropic periodic bandgap structures

Forbidden gaps in Sole folded-type anisotropic periodic structures are anal yzed. The azimuth angle in the first quadrant and unequal thicknesses of al ternating uniaxial layers are considered. Unit-cell translation matrices ar e explicitly given at oblique and normal incidences. Implicit dispersion re lations are obtained. Birefringence and normal group velocities are determi ned. Numerical examples make the distinction between the gaps determined by one root and those determined by two roots of the eigenvalue equation. Whe n layers have unequal thicknesses, the gap determined by one root is much w ider, but inside the gap the reflectivity is lower than unity, breaks appea r, and an increased birefringence results. (C) 2001 Optical Society of Amer ica OCIS codes: 230.4170, 260.1180, 260.1440, 260.5430, 310.6870, 350.2460.