Polarized photoluminescence excitation spectroscopy of single-walled carbon nanotubes

The polarized photoluminescence excitation spectra of twenty-five single-walled carbon nanotube species are reported. For light polarized along the nanotube axis, the main absorption resonance at E(22) shows sidebands attributed to phonon assisted absorption. Sidebands to E(11) have a diameter dependent energy and are assigned to excited excitonic states. Along with longitudinal excitations, several transverse excitations are identified. The transverse E(12) resonance has a specific family pattern with energy close to E(22). Comparison with theory provides an estimate of the strength of the Coulomb interaction.