Inelastic scattering of surface plasmons in oscillating metallic waveguides

By using a metal-insulator-metal waveguide with temporally oscillating core width, the single frequency of incident surface plasmon polaritons (SPPs) could be converted to many discrete frequencies with equivalent intervals. The conversion efficiency is affected by the waveguide structure and also the amplitude and frequency of the oscillation. Finite-difference time-domain simulations revealed that the SPP frequency shift behavior is analogous to the spatial light diffraction in optical waveguide arrays. The discrete frequencies of SPPs can further be controlled by varying the initial phase of the waveguide core width oscillation. The results are explained analytically using the coupled mode theory. (C) 2011 American Institute of Physics. [doi:10.1063/1.3605677]