Dispersion and lifetimes of electromagnetic modes attached to strongly textured slab waveguides

The influence of strong, two-dimensional (2D) periodic texture on the dispersion and lifetimes of resonant electromagnetic modes localized in the vicinity of thin (80 to 155 nm) GaAs membranes supported on thick (1 to 2 m) wet-oxidized AlAs cladding layers is reported. A method of extracting this information by fitting Fano-like features in broadband specular reflectivity spectra is described in detail, and applied to samples containing both triangular and square 2D lattices. A new and easier method of probing the properties of these modes is also demonstrated. It involves incorporating a superlattice of defects in the principal crystal lattice, and monitoring the defect diffraction spectrum, rather than the specular reflectivity.