  We studied theoretically the population dynamics and the absorption spectrum
of hybrid nanosystem consisted of a matal nanoparticle (MNP) and a
semiconductor quantum dot(SQD). We investigated the exciton-plasmon coupling
effects on the population dynamics and the absorption properties of the
nanostructure. Our results show that the nonlinear optical response of the
hybrid nanosystem can be greatly enhanced or depressed due to the
exciton-plasmon couplings. The results obtained here may have the potential
applications of nanoscale optical devices such as optical switches and quantum
devices such as a single photon transistor.
