Nonlinear Optical Properties of Carbon Nanotubes from First Principles

The optical excitation spectra of both semiconducting and metallic single-walled carbon nanotubes (SWNTs) as well as other 1D materials are dominated by exciton states of large binding energy and well defined symmetry in the group of the k-vector along the periodic direction. The optical oscillator strength is transferred almost entirely from the continuum into the excitons and the corresponding exciton-phonon states. Recent experiments have probed the spectral structure of the excited states of various symmetry in SWNTs using nonlinear optics techniques such as ultrafast spectroscopy, multi-photon spectroscopy, and phonon-assisted spectroscopy. We have developed and applied a new method based on the first-principles GW-Bethe Salpeter approach to the study of the nonlinear optical properties of the SWNTs. Supported by NSF Grant No. DMR07-05941, US DOE Contract No. DE- AC02-05CH11231 and DOE CSGF grant DE-FG02-97ER25308 and computational resources from Teragrid and NERSC.