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Coherent control on single quantum dots

This work is performed in collaboration with X. Marie and T. Amand from the LPCNO-INSA(Toulouse).

The energy states in semiconductor quantum dots are discrete as in atoms, and quantum states can be coherently controlled with resonant laser pulses. Long coherence times allow the observation of Rabi-flopping of a single dipole transition in a solid state device, for which occupancy of the upper state depends sensitively on the dipole moment and the excitation laser power. The robust population inversion in a single quantum dot is demonstrated using an optical technique that exploits rapid adiabatic passage from the ground to an excited state through excitation with laser pulses whose frequency is swept through the resonance. This observation in photoluminescence experiments is made possible by introducing a novel optical detection scheme for the resonant electron hole pair (exciton) generation.

References :

A. Debnath, C. Meier, B. Chatel and T. Amand, Chirped laser excitation of quantum dot excitons coupled to a phonon bath, PRB 86, 161304 (R) (2012)

C.-M. Simon, T. Belhadj, B. Chatel, T. Amand, P. Renucci, A. Lemaitre, O. Krebs, P. A. Dalgarno, R. J. Warburton, X. Marie and B. Urbaszek, "Robust quantum dot exciton generation via adiabatic passage with frequency-swept optical pulses" Physical Review Letters 106, 166801 (2011).