Microcavities, texture symmetry, and photonic bandgaps

The dispersions of the waveguide modes of planar and wavelength-scale textu red microcavities are measured and compared. We show that when just one mir ror of the microcavity has a corrugated profile, the waveguide modes are dr amatically altered with Bragg scattering from the texture leading to a seri es of flat bands and photonic band gaps. In contrast, we further show that when both mirrors possess a similar in-phase corrugation, although Bragg sc attering of the modes still occurs, no bandgaps or band edges are formed. T he results are explained by modeling the electric field distribution in the microcavity, and the implications of the findings for emissive devices are discussed. (C) 2001 Optical Society of America OCIS codes: 310.2790, 310.6 860, 230.3670, 050.2770.