Independent dynamic acousto-mechanical and electrostatic control of individual quantum dots in a LiNbO 3-GaAs hybrid

A single InGaAs∕GaAs quantum dot is addressed in a two-color femtosecond transmission experiment in the optical near-field of a nanometer-scale shadow mask. After resonant excitation of the wetting layer beneath the nanoisland, we detect transmission changes of the quantum dot with narrow band femtojoule probe pulses. We find bleaching signals in the order of 10−5 that arise from individual interband transitions. Moreover, the nonlinear optical response reveals a picosecond dynamics associated with carrier relaxation in the quantum dot. As a result, we have developed an ultrafast optical tool for both manipulation and readout of a single self-assembled quantum dot.

PACS 78. 47.+p, 78.67.Hc Carrier dynamics in InGaAs/GaAs quantum dots is analyzed with highly sensitive femtosecond transmission spectroscopy. In a first step, measurements on a large ensemble of nanoislands reveal the dynamical electronic filling of quantum dots from the surrounding wetting layer. Most interestingly, we find a spinpreserving phonon mediated scattering into fully localized states within a few picoseconds. Then, individual artificial atoms are isolated with metallic shadow masks. For the first time, a single self-assembled quantum dot is addressed in an ultrafast transmission experiment. We find bleaching signals in the order of 10-that arise from individual interband transitions of one quantum dot. As a result, we have developed an ultrafast optical tool for both manipulation and read-out of a single self-assembled quantum dot.

Carrier dynamics in InGaAs/GaAs quantum dots is analyzed with highly sensitive femtosecond transmission spectroscopy. In a first step, measurements on a large ensemble of nanoislands reveal the dynamical electronic filling of quantum dots from the surrounding wetting layer. Most interestingly, we find a spin-preserving phonon mediated scattering into fully localized states within a few picoseconds. Then, individual artificial atoms are isolated with metallic shadow masks. For the first time, a single self-assembled quantum dot is addressed in an ultrafast transmission experiment. We find bleaching signals in the order of 10 -5 that arise from individual interband transitions of one quantum dot. As a result, we have developed an ultrafast optical tool for both manipulation and read-out of a single selfassembled quantum dot.

Carrier dynamics in InGaAs/GaAs quantum dots is analyzed with highly sensitive two-color femtosecond transmission spectroscopy. Especially, a single artificial atom is addressed in the optical near-field of a nanometer scale shadow mask. Resonantly exciting the wetting layer beneath the nanoisland, we detect transmission changes of the quantum dot with narrowband femtojoule probe pulses. We find bleaching signals in the order of 10 −5 that arise from individual interband transitions. Moreover, the nonlinear optical response reveals a picosecond dynamics associated with carrier relaxation in the quantum dot. As a result, we have demonstrated an ultrafast optical tool for both manipulation and read-out of a single self-assembled quantum dot.