SCULPTURED THIN-FILMS - I - CONCEPTS

A report on the conceptualization of sculptured thin films (STFs), as well as on recent theoretical advances thereon, is presented. The morp hology of a STF is described in terms of a spatially varying unit vect or called the director, whose piecewise specification assists in setti ng up frequency-dependent constitutive relations of the STF. These rel ations lead in turn to a 4x4 matrix differential equation for the prop agation of electromagnetic waves in the STF. Optical, suboptical, infr ared and even millimeter-wave applications are possible, as well as ac oustic and piezoelectric ones.