Nonlinear and ultrafast optical response in single-walled carbon nanotubes

Ultrafast Optical Spectroscopy of Single-Walled Carbon Nanotubes

A wavelength-dependent, near-infrared pump-probe study has been performed on micelle-suspended Single-Walled Carbon Nanotubes (SWNTs) whose linear absorption spectra show chirality-assigned peaks. Two distinct relaxation regimes were observed: fast (0.3-1.2 ps) and slow (5-20 ps). The slow component, which has previously been unobserved in pump-probe measurements of bundled tubes, was resonantl...

Ultrafast Optical Spectroscopy of Micelle-Suspended Single-Walled Carbon Nanotubes

We present results of wavelength-dependent ultrafast pump-probe experiments on micelle-suspended single-walled carbon nanotubes. The linear absorption and photoluminescence spectra of the samples show a number of chirality-dependent peaks, and consequently, the pump-probe results sensitively depend on the wavelength. In the wavelength range corresponding to the second van Hove singularities (VH...

Optical Spectroscopy of Single-Walled Carbon Nanotubes

Ultrafast spectroscopy of excitons in single-walled carbon nanotubes.

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 th...

Ultrafast exciton dephasing in semiconducting single-walled carbon nanotubes.

Femtosecond two-pulse degenerate four-wave mixing spectroscopy was applied to study the exciton dephasing in a broad range of excitation intensities and lattice temperatures. We find that both exciton-exciton and exciton-phonon scattering have profound effects on the dephasing process. The dominant phonon mode involved in the dephasing is identified as the out-of-plane, transverse optical mode ...