Spatial Bloch oscillations of plasmons in nanoscale metal waveguide arrays

A kind of metal waveguide array (MWGA) structures designed for observing spatial plasmon Bloch oscillations (BOs) in nanoscale is presented. The gradient of plasmon propagation constants across the MWGAs is realized by gradually changing the dielectric constant of the dielectrics filling in the guides. Plasmon BOs in the MWGAs manifest themselves as periodic breathing and transverse motion under the conditions of initial single and multiple waveguide excitations, respectively. Analytical results from the coupled wave theory are confirmed by finite-difference time-domain numerical simulations. (C) 2007 American Institute of Physics.