Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod

We theoretically investigated the dynamics of exciton populations [ρyy(t) and ρxx(t)] on two orthogonal polarization eigenstates (∣x⟩ and ∣y⟩) and the polarization ratio P(t)=[ρyy(t)−ρxx(t)]∕[ρyy(t)+ρxx(t)] of an anisotropic InGaAs quantum dot modulated by the surface plasmon of an Au nanorod (NR). In the resonance of longitudinal surface plasmon of AuNR, the polarization ratio P(t) increases from 0.22 to 0.99 during the excitation due to the efficient enhancement of Rabi frequency of the transition between the ∣y⟩ and vacuum states, and decreases from 0.02 to −0.92 after the excitation pulse due to the enhancement of decay rate of the ∣y⟩ state. This offers an approach to modulate the dynamic polarization ratio of radiative emissions.