Circularly polarized light in coupled quantum dots

Circular light polarization is studied in vertically self-assembled coupled quantum dots (QDs). We have calculated the emitted light polarization along the direction of spin-polarized states (considering 100% spin-polarized states). We have considered ellipsoidally shaped QDs made with InAs/GaAs. It has been shown that the interdot distance is a crucial parameter for circularly polarized light. For small, elongated QDs with small interdot distance the light polarization along the plane perpendicular to the growth direction is P(110)similar to 40%. In the case of large and elongated (e not equal 1.0) QDs with large interdot distance the light polarization is only P(110)similar to 5%. Comparison with experimental results has been highlighted for the case of large interdot distances (uncoupled QDs).