Rainbow trapping and releasing by chirped plasmonic waveguides at visible frequencies

摘要

We report on “trapping rainbow” on silver films covered by a one-dimensional chirped dielectricngrating.We attribute the trapping effect to correlative dispersive relation between the excited surfacenplasmon polaritons u0002SPPsu0003 and the lattice constant of the dielectric grating on the metal film, whichnresults in localization of SPPs of different frequencies at different spatial positions. We furthernreveal that, by attaching another uniform dielectric grating on the other side of the metal film andnreal time tuning the refractive index of the grating, the trapped rainbow can be released in sequence.nAnalytical results are demonstrated by finite-difference time-domain simulation. © 2010 AmericannInstitute of Physics. u0004doi:10.1063/1.3502487