Figure 2

(a) The schematic of unit cells of tapered and uniform OS-HMM waveguide arrays. (b,c) The dispersion relations of the uniform O-HMM waveguide for two widths of (b) 13 and (c) 33 mm, while the widths of S-HMM waveguide are assumed to be 9 and 22 mm. (d,e) The dispersion relations of the uniform S-HMM waveguide for two widths of (d) 9 and (e) 22 mm, while the widths of O-HMM waveguide are assumed to be 13 and 33 mm. The lattice constants along x-direction and y-direction are assumed to be = 57 mm and
= 34 mm, respectively. All the other parameters are the same as those in Fig. 1.