Exciton-plasmon coupling and biexcitonic nonlinearities in individual carbon nanotubes

Optical response of small-diameter (≲1nm) semiconducting carbon nanotubes is discussed under the variable exciton-surface-plasmon coupling both in the linear excitation regime and in the non-linear excitation regime with the photoinduced biexcitonic states formation. The Rabi splitting effect ∼0.1 eV takes place in both cases, indicating the strong exciton-plasmon coupling both for single excitons and for biexcitons as the exciton energy is tuned to the nearest interband surface plasmon resonance of the nanotube. These results should be useful for the development of new tunable optoelectronic device applications of optically excited semiconducting carbon nanotubes, including the strong excitation regime with optical non-linearities.