Figure 2: (a) Schematic of a plasmonic waveguide system consisting of a metal-dielectric-metal (MDM) waveguide side-coupled to a periodic array of MDM stub resonators. (b) Dispersion relation of the plasmonic waveguide system of (a) calculated using FDFD (black solid line). Results are shown for a silver-air structure with 𝑑 = 1 0 0  nm, 𝐿 = 2 2 0  nm, 𝑤 0 = 𝑤 = 5 0  nm. Also shown is the dispersion relation for lossless metal (red dash-dotted line) and the resonance frequency 𝜔 r e s (black dashed line) ( 𝜔 r e s 0 . 0 6 7 2 𝜋 𝑐 / 𝑑 corresponding to 𝜆 r e s 1 . 5 𝜇 𝑚 ). (c) Reciprocal of the group velocity 𝑣 𝑔 of light in the plasmonic waveguide system as a function of frequency. All parameters are as in (b). (d) Magnetic field profile of the supported optical mode in the system at 𝜆 0 = 1 . 5 5 μm. All other parameters are as in Figure 2(b). (e) Reciprocal of 𝑣 𝑔 versus propagation length 𝐿 𝑝 for the plasmonic waveguide system of Figure 2(a) at 𝜆 0 = 1 . 5 5 μm calculated using FDFD. Results are shown for 𝑑 = 1 0 0  nm (upper blue curve) and 𝑑 = 2 0 0  nm (lower red curve) as 𝐿 is varied. All other parameters are as in (b).