  Carbon nanotubes provide a rare access point into the plasmon physics of
one-dimensional electronic systems. By assembling purified nanotubes into
uniformly sized arrays, we show that they support coherent plasmon resonances,
that these plasmons enhance and hybridize with phonons, and that the
phonon-plasmon resonances have quality factors as high as 10. Because coherent
nanotube plasmonics can strengthen light-matter interactions, it provides a
compelling platform for surface-enhanced infrared spectroscopy and tunable,
high-performance optical devices at the nanometer scale.
