Folded and confined one-dimensional plasmons in modulated wires

We demonstrate theoretically and experimentally that one-dimensional plasmons confined in doped wires are either extended or longitudinally confined when the lateral width of the wires is periodically modulated. Theoretical dispersion curves, calculated within a classical framework, reproduce well the experimental dispersion deduced from Raman scattering on deep etched modulated wires. Zone-edge gap openings, increasing with the modulation amplitude, are exhibited. We show that deep etching allows good control of complex geometries and provides quasiabrupt boundary conditions.