Theory of nonlinear optical properties of C60-derived nanotubes

We study the third-order optical nonlinearities (characterized by the second-order hyperpolarizabilities gamma) of C-60-derived nanotubes. It is found that the static gamma magnitudes of armchair (C60+ix10) and zigzag (C60+ix18) nanotubes obey their own exponent laws given by gamma/gamma(60)=(1+ix10/60)(3.15) and gamma/gamma(60)=(1+ix18/60)(2.98), respectively, where gamma(60) is the static gamma magnitude of C-60 and i is a positive integer. Also, the dynamical nonlinear optical responses of armchair and zigzag nanotubes are studied in detail. It is found that the symmetry and caps of these nanotubes have a large effect on their third-order optical nonlinearities. By these detailed studies, we find that armchair and zigzag nanotubes can compete with polymeric materials for photonic applications due to their large nonresonant and resonant third-order optical nonlinearities. (C) 1998 American Institute of Physics.