Spectral Green´s functions for multilayer media in a simple form

A spatial Green´s function of multilayer media by complex images, is now very simple in form. The spectral Green´s function, from which the spatial function is derived, is still very cumbersome especially for media of many layers. The paper completes the simplification, by rewriting the spectral function in a novel series of wave transmission matrices. This leads to much simplicity in evaluation and to physical insights.