Determining the natural absorption and radiation modes of lossy periodic structures using energy absorption interferometry

Energy absorption interferometry is presented in the spectral domain in order to allow an easier representation of fields for layered media. A formulation comprising a single interface between semi-infinite media is presented and a compact representation of the fringe pattern is obtained assuming that two sources with varying relative phase are used. Limit cases of continuous lossy layers and of very fine parallel strips are considered and different full-wave approaches are discussed. Simulation results show how the structure of the absorbing medium becomes visible when the sources are placed closer to the lossy medium.