Effective tuning of exciton polarization splitting in coupled quantum dots

The polarization splitting of the exciton ground state in two laterally coupled quantum dots under an in-plane electric field is investigated, and its effective tuning is designed. It is found that there are significant Stark effect and anticrossing in energy levels. Due to the coupling between inter- and intradot states, the absolute value of polarization splitting is significantly reduced, and it could be tuned to zero by the electric field for proper interdot separations. The scheme of the authors is interesting for the research on the quantum dot–based entangled-photon source.