Computational photonics from the bottom-up

Optimizing the performance of optical fibres or photonic devices often boils down to the identification of a proper dielectric material, or to a systematic modification of an existing basic material. With modern ab initio simulation methods based on density functional theory, it is possible to model dielectric properties from the bottom-up. Starting with the atomic and electronic structure of the underlying dielectrics, one may systematically search for the most stable materials with the best dielectric properties, and use that data as part of subsequent realistic simulations of photonic structures and devices based on Maxwell´s equations. In the following we will discuss certain aspects of modern ab initio methods used to determine the frequency-dependent dielectric function of a given material, and present some illustrative examples in terms of the dielectric properties for some crystalline phases of SiO₂.