Semiconductor quantum dots (QDs) are promising candidates for ultrafast coherent qubit manipulation using laser pulses. In inhomogeneous QD ensembles, macroscopic optical polarization decays rapidly due to dephasing, but this is reversible in photon echoes. This paper proposes a method to control the echo emission time by introducing an additional resonant control pulse with a 2π area. The control pulse, depending on its timing, slows dephasing or rephasing, shifting the echo emission time by up to 5 ps in self-assembled (In,Ga)As QDs. This provides a versatile method for precise control of photon echo timing.

Alexander N. Kosarev, Hendrik Rose, Sergey V. Poltavtsev, Matthias Reichelt, Christian Schneider, Martin Kamp, Sven Höfling, Manfred Bayer, Torsten Meier, Ilya A. Akimov