title: Gap maps and intrinsic diffraction losses in one-dimensional photonic crystal slabs.
abstract: A theoretical study of photonic bands for one-dimensional (1D) lattices embedded in planar waveguides with strong refractive index contrast is presented. The approach relies on expanding the electromagnetic field on the basis of guided modes of an effective waveguide, and on treating the coupling to radiative modes by perturbation theory. Photonic mode dispersion, gap maps, and intrinsic diffraction losses of quasi guided modes are calculated for the case of self-standing membranes as well as for silicon-on-insulator structures. Photonic band gaps in a waveguide are found to depend strongly on the core thickness and on polarization, so that the gaps for transverse electric and transverse magnetic modes most often do not overlap. Radiative losses of quasiguided modes above the light line depend in a nontrivial way on structure parameters, mode index, and wave vector. The results of this study may be useful for the design of integrated 1D photonic structures with low radiative losses.
authors.affiliation: Istituto Nazionale per la Fisica della Materia and Dipartimento di Fisica Alessandro Volta, Università di Pavia, Via Bassi 6, I-27100 Pavia, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Gerace
authors.forename: Lucio Claudio
authors.initials: LC
authors.lastname: Andreani