Theoretical Study of Phase Conjugation in Mesoscopic Interaction Volumes

In order to study the possible phase conjugation of optical near-fields, it is necessary to go beyond the slowly varying envelope- and electric dipole approximations that are normally applied in phase conjugation studies where spatially non-decaying (or at least slowly decaying) modes are mixed. In the present dissertation, the minimal coupling Hamiltonian is used to create a microscopic theoretical description of degenerate four-wave mixing. It is a semiclassical description where the electromagnetic field is treated as a classical quantity and the active medium is treated quantum mechanically. Numerical results are given for a single-level quantum well (exclusively intraband contributions) and for a two-level quantum well (mainly interband contribution). Focusing of a phase conjugated field is also discussed. (Full-length abstracts in Danish and English included).