Optical Properties of Thin Films and the Berreman Effect

摘要: The measurement of reflection and transmission normally incident light to obtain the optical constants a material is usual tool in solid-state spectroscopy. If under investigation thin film, interaction electromagnetic field with sample can be enhanced by oblique incidence. p-polarized, structures spectra are observed at frequencies transverse (TO) longitudinal (LO) resonances. LO structure — called Berreman effect generated surface charges due normal component electric field. We discuss this for three cases: free film metallic back substrate films on both sides. dependence energy-loss function Im {−1/ɛ} thickness discussed. For idealized systems simple formulae derived characteristic parameter, thickness, obtained. Films show maximum effect. Intuitive arguments given explain Examples application characterize very