Propagation loss in two-dimensional polaritonic photonic crystal waveguides

By means of a plane-wave-based transfer-matrix method, we present an extensive study of propagation loss in two-dimensional polaritonic photonic crystal waveguides with limited cladding wall thickness. Our method has an intrinsic advantage in this case, because the effect of index dispersion can be easily incorporated as the transfer matrix is defined at each frequency separately. We examine the dependence of propagation loss on the waveguide wall thickness. We find that the propagation loss exponentially decays with increasing the waveguide wall thickness and exhibits very complex behavior with respect to the excitation frequency. We also find that the propagation loss in our structure exhibits completely different varying behavior from that of the similar passive structure studied in [Z.Y. Li, K.M. Ho, Phys. Rev. Lett. 92 (2004) 063904]. The novel behavior can be explained by the fact that these two structures have different guided mode dispersions.