Polaritons in Semiconductor Layer Structures

Abstract

The infrared optical response of layered structures composed of polar semiconductor materials is strongly influenced by resonant excitation of phononand plasmon-supported bulk polaritons. In addition, subtle effects are caused by interface modes (surface polaritons, surface guided waves) at which electromagnetic radiation is mediated parallel to the interfaces of thin-film structures. Precise information on phonon and plasmon mode parameters can be obtained from measurement and model analysis of the frequency-dependent sample response, e.g., in terms of the complex ratio ρ in (2.1).¹ A rich variety of plasmon-phonon supported bulk and interface modes can occur in thin-film structures composed of polar semiconductors, as will be shown here. A brief outline of the concept of bulk and interface polaritons is given in the following section. The occurrence of surface polaritons and surface guided waves in polar semiconductor thin-film structures is explained and demonstrated.