In single-walled carbon nanotubes (SWNTs), their electronic and vibrational structure as well as their charge-carrier dynamics are crucial for potential ultrasmall optical device applications. SWNT properties have now been obtained from optical absorption and time-resolved photoemission and, at the single-nanotube level, by resonance Raman scattering and photoluminescence studies. This article presents an overview of SWNT photophysics, discussing important findings for the characterization of carbon nanotube properties and directions for future research and potential applications. The unique optical properties observed in SWNTs are due to the one-dimensional confinement of electronic states, resulting in van Hove singularities in the nanotube density of states. Optical measurements of phonons, charge-carrier dynamics, and the electronic transition energy van Hove singularities are discussed.
