Coupling of photon energy via a multiwalled carbon nanotube array

Fluorescent beads were excited by a laser beam coupled through a multiwalled carbon nanotube array. The images of the fluorescent beads showed a distinctive dependence on the polarization direction of the laser beam owing to the surface plasmons induced from the metallic property of the array. The thickness of the array is 2 μm as compared to the metallic films of tens of nanometers in thickness that are conventionally used for surface plasmon excitation. This remarkable photon coupling capacity of a multiwalled carbon nanotube array is attributed to the confinement of electrons in its outermost tube shells and ballistic transport.