%0 Journal Article %J Nanoscale %D 2014 %T Ultra-broadband unidirectional launching of surface plasmon polaritons by a double-slit structure beyond the diffraction limit %A Chen, Jianjun %A Sun, Chengwei %A Li, Hongyun %A Qihuang Gong %X

Surface-plasmon-polariton (SPP) launchers, which can couple the free space light to the SPPs on the metal surface, are among the key elements for the plasmonic devices and nano-photonic systems. Downscaling the SPP launchers below the diffraction limit and directly delivering the SPPs to the desired subwavelength plasmonic waveguides are of importance for high-integration plasmonic circuits. By designing a submicron double-slit structure with different slit widths, an ultra-broadband (>330 nm) unidirectional SPP launcher is realized theoretically and experimentally based on the different phase delays of SPPs propagating along the metal surface and the near-field interfering effect. More importantly, the broadband and unidirectional properties of the SPP launcher are still maintained when the slit length is reduced to a subwavelength scale. This can make the launcher occupy only a very small area of

%B Nanoscale %I ROYAL SOC CHEMISTRY %C THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND %V 6 %P 13487-13493 %8 NOV %G eng %9 Article %] 000344836800025 %R 10.1039/c4nr02938k