Metal heterowaveguide superlattices for a plasmonic analog to electronic Bloch oscillations

A metal heterowaveguide superlattice constructed by alternately stacking two metal gap waveguides with gradually changed geometric thicknesses for observing time-resolved plasmon Bloch oscillations (PBOs) is presented. Analytical result from the transfer matrix method reveals the appearance of tilted plasmonic minibands and minigaps, and plasmonic Wannier-Stark ladder in frequency domain, indicating the existence of time-resolved PBO effects in such superlattices. Finite-difference time-domain simulations on the dynamic evolution of plasmon propagation in the superlattices demonstrate the analytical prediction. (c) 2007 American Institute of Physics.