Voltage-controlled coherent population transfer in an asymmetric semiconductor quantum dot molecule

We present a scheme for the coherent population transfer of a three-level system in a quantum dot molecule by means of the interdot tunnel-coupling which can be controlled by a bias voltage. Under proper combination of the pump laser pulse and the tunnel-coupling pulse, an almost complete population transfer from the state without excitations to the indirect exciton state can be achieved. Additionally, by tuning the tunnel-coupling pulse, an arbitrary coherent superposition of the two states can also be prepared.