Scattering of electromagnetic cylindrical waves by an isolated, semi-infini
te, open-ended, single-shell, zigzag carbon nanotube (CN) is considered in
the optical regime. The CN is modeled as a smooth homogeneous cylindrical s
urface with impedance boundary conditions known from quantum-mechanical tra
nsport theory. An exact solution of the diffraction problem is obtained by
the Wiener-Hopf technique. The differences between the scattering responses
of metallic and semiconducting CNs are discussed.