“…During the last decade different multilayered waveguiding structures had been studied: the magnetic photonic crystals [32][33][34], nanocomposite multilayers and photonic crystal waveguides [35], silicon-based hybrid gap surface plasmon polariton waveguides [36], nanophotonic and plasmonic waveguides [37] and multilayer graphene waveguides [38]. Besides, four-layer structures due to the enhanced field confinement in guiding layer [39,40] can be effectively used in medical applications such as label free biosensors.…”