Slow light in insulator-metal-insulator plasmonic waveguides

We study numerically the slow-light capability of insulator-metal-insulator (IMI) plasmonic waveguides. Metal-induced losses are included in the calculation of the dispersion relations, and their effect on the slow-light properties of the waveguide is investigated. In addition to reducing the propagation lengths of surface plasmon polaritons, losses are found to limit the achievable slowdown factors and the practical potential of the device. To alleviate the problem, we consider active materials. Using realistic parameters, we find that a spectral region is then formed where a slow-light pulsed signal can achieve infinite propagation lengths or be amplified. The optical buffering capabilities of the IMI waveguide with losses are analyzed, and we conclude that while losses limit the buffering capabilities of the passive device, the use of active materials may combat the problem effectively from an application point of view. (C) 2011 Optical Society of America