Dipole-Dipole Interaction Model of Optical Near Field

Although one can acquire some information about the optical near field by solving the approximated Maxwell and Schrodinger equations simultaneously, this derivation requires numerical calculations with a very long computation time. Even though numerical results are possible, it is very difficult to obtain an intuitive physical picture of the optical near field. In order to overcome this difficulty, Chaps. 4–9 seek to review theoretical models that offer intuitive concepts to analyze the physical meaning of the optical near field and the relevant experimental results. The present chapter presents the simplest theoretical model to describe the phenomena presented in Chap. 2. Section 4.1 imposes a condition on the size of material systems in which the optical near field is investigated. Under this condition, Sect. 4.2 describes the basic role of a probe from the viewpoint of the dipole-dipole interaction. Section 4.3 discusses the characteristics of fiber probes, which depend on their shape and composition.