Broadband slow-light in graded-grating-loaded plasmonic waveguides at telecom frequencies

We explore developing graded-grating-loaded plasmonic waveguide for “trapped rainbow” at telecom frequencies by modulating feature sizes of gratings to extend its operational frequencies to the infrared domain. We show that such a structure is capable of localizing light waves of different infrared frequencies at different spatial positions. Such a slow-light device offers the advantages including a wide spectral band, a long photon lifetime and strong confinement, which may enable practical applications in various nanophotonic circuits.