Photonic band structure of dielectric membranes periodically textured in two dimensions

The real and imaginary photonic band structure of modes attached to two-dimensionally textured semiconductor membranes is determined experimentally and theoretically. These porous waveguides exhibit large (1000 ${\mathrm{cm}}^{-1}$ at 9500 ${\mathrm{cm}}^{-1})$ second-order optical gaps, highly dispersive lifetimes, and bands with well-defined polarization along directions of high symmetry.