Magnetooptische Effekte bei inkohärenter Vielfachreflexion - Teil I: Iterationsverfahren -

The primary magnetooptical ("mo") effects are the Faraday-effect and the mo Kerreffect. In both cases the polarisation status of light is modified from a starting linear polarisation into an elliptic one including a rotation of the main axis of the ellipses. In the classical notation, the Faraday-effect in its definition is a pure volume effect and the mo Kerr-effect is defined as a interface effect in reflection. But corresponding to the boundary conditions of electromagnetic waves, we also have a mo Kerr-effect in transmission at the interface between two media having different complex mo refraction indices. The paper is concerned with the problem of superimposition of mo influences if multireflection of light is present in a planparallel sample at normal incidence. In contrast to the problem of coherent superposition of the electromagnetic fields of multireflected beams, the paper is concerned with the problem of incoherent beam superimposition. The paper leads to the observable results of mo transmission and reflection effects respectively, by means of an iterative addition of the relevant radiation flux densities of the multireflected beams. The relevant radiation flux densities are the intensity components with respect to the orientation of the analyser. With respect to the integral measuring results of the mo effects in transmission and reflection, a main point of the discussion is to state that the mo polarisation modification in the case of incoherent multireflection is not to be understood as a sort of mean value of the mo spectra in the case of coherent superposition of multireflected beams. In contrast, in the incoherent case we find an "alienation" of the mo spectra possibly leading to a misinterpretation of the involved microphysical processes. The numerical results of two examples are presented. In each case the spectra of coherent as well as incoherent beam superposition are given for comparison. The final discussion contents the remark, that the methode of polarisation modulation between the right and left circular polarisation mode leads to different mo results in comparison with the measurements using a rotating analyser if incoherent multireflection is present. Therefore different definitions of the resulting mo effects must be observed. The presented method of iteration is useful for calculating the expected experimental results based on models as well as to analyse the measurements by variation of the parameters using an appropriate procedure.