Abstract: Ultrashort broadband THz pulses are applied to probe the femtosecond charge-carrier dynamics of laser-excited graphite and carbon nanotubes. In graphite, the electrons lose more than 90% of their excess energy which selectively heat up a very small subset of strongly coupled optical phonons. In the nanotube sample, the absence of a free-carrier re-sponse is due to the photogeneration of strongly bound excitons in the semiconducting tubes. A pronounced dichroism of a spectral feature of increased absorption gives direct evidence of excitations which are localized on a 100-nm length scale.
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