Slow-light dispersion by transparent waveguide plasmon polaritons

We propose a classical analogue of electromagnetically induced transparency for a two-level ensemble interacting with two orthogonal optical modes. We show that a single localized plasmon resonance of a metal nanoparticle ensemble coupled to counter-propagating modes of a dielectric waveguide generates a slow transparent waveguide-plasmon polariton. Dispersion is controllable by tuning the coupling strengths of localized plasmon and waveguide modes, while maintaining extremely low loss at the system's transparency. Strong coupling in such plasmonic hybrid systems leads to large group index-bandwidth products.