title: Ultrafast spectroscopy of excitons in single-walled carbon nanotubes.
abstract: We studied the femtosecond dynamics of photoexcitations in films containing semiconducting and metallic single-walled carbon nanotubes (SWNTs), using various pump-probe wavelengths and intensities. We found that confined excitons and charge carriers with subpicosecond dynamics dominate the ultrafast response in semiconducting and metallic SWNTs, respectively. Surprisingly, we also found from the exciton excited state absorption bands and multiphoton absorption resonances in the semiconducting nanotubes that transitions between subbands are allowed; this unravels the important role of electron-electron interaction in SWNT optics.
authors.affiliation: Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: O J
authors.initials: OJ
authors.lastname: Korovyanko
authors.forename: C-X
authors.initials: CX
authors.lastname: Sheng
authors.forename: Z V
authors.initials: ZV
authors.lastname: Vardeny
authors.forename: A B
authors.initials: AB
authors.lastname: Dalton
authors.forename: R H
authors.initials: RH
authors.lastname: Baughman