Figure 2

(a) Band gap diagram of the multilayer with semi-infinite stacks calculated for TE polarization. The white area indicates the location of the forbidden band. Light line and dispersion curves of the BSW for the platform alone and for the platform with a 100-nm/500-nm PR coating are plotted, respectively. (b) Experimental dispersion relations of the bare multilayer (platform) and the case with a 100-nm-thick PR layer coating are obtained by detecting the far-field leakage in the reflected beam for varying θ and λ. (c) The effective index contrast of the BSW between the two media, namely, the platform (PR thickness=0) and the coated layers (PR thickness: 100–500 nm), are extracted from RCWA simulations. The star indicates the measured Δn deduced from the measured dispersion curve in (b) for a 100-nm PR coating. BSW, Bloch surface wave; PR, photoresist; RCWA, rigorous coupled-wave analysis; TE, transverse electric.