Flat photonic bands in guided modes of textured metallic microcavities

A detailed experimental study of how wavelength-scale periodic texture modi fies the dispersion of the guided modes of lambda/2 metal-clad microcavitie s is presented. We first examine the case of a solid-state microcavity text ured with a single, periodic corrugation. We explore how the depth of the c orrugation and the waveguide thickness affect the width of the band gap pro duced in the dispersion of the guided modes by Bragg scattering off the per iodic structure. We demonstrate that the majority of the corrugation depths studied dramatically modify the dispersion of the lowest-order cavity mode to produce a series of substantially flat bands. From measurements of how the central frequency of the band gap varies with direction of propagation of the guided modes, we determine a suitable two-dimensional texture profil e for the production of a complete band gap in all directions of propagatio n. We then experimentally examine band gaps produced in the guided modes of such a two-dimensionally textured microcavity and demonstrate the existenc e of a complete band gap for all directions of propagation of the lowest-or der TE-polarized mode. We compare our experimental results with those from a theoretical model and find good agreement. Implications of these results for emissive microcavity devices such as light-emitting diodes are discusse d.