Enhancing Kerr nonlinearity of a strongly coupled exciton-plasmon in hybrid nanocrystal molecules

The optical nonlinearity of hybrid nanocrystal molecules composed of semiconductor and metal nanoparticles with a weak probe in a strong control field is investigated theoretically. Excitons in such a hybrid molecule demonstrate novel optical properties due to the coupling between excitons and plasmons. It is shown that Kerr nonlinear coefficients as functions of the detuning of the control field from the exciton frequency and the centre-to-centre distance between the two nanoparticles are greatly enhanced due to exciton-plasmon couplings.