S. V. Poltavtsev

Effect of thermal annealing on the hyperfine interaction in InAs/GaAs quantum dots

The hyperfine interaction of an electron with the unpolarized nuclei in thermally annealed self-assembled InAs/GaAs quantum dots (QDs) is theoretically analyzed. For this purpose, the thermal annealing process of the quantum dots is numerically modeled to obtain the nuclear composition as well as the electron ground state in the QDs. To check the reliability of calculations, the ground-state excitonic transition energies are compared with photoluminescence data from a set of annealed dots. From these results, the electron localization volume and the partial contributions of the In, Ga, and As nuclei to the hyperfine interaction are calculated as functions of annealing temperature. The contribution of the indium nuclei to the hyperfine interaction dominates up to high temperatures of the annealing

Magnetic-Field Control of Photon Echo from the Electron-Trion System in a CdTe Quantum Well: Shuffling Coherence between Optically Accessible and Inaccessible States

({T}_{a}=980\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C})

Photon echo transients from an inhomogeneous ensemble of semiconductor quantum dots

, for which the In content in the dots does not exceed 25%. Simulations of the effect of the nuclear-spin fluctuations on the electron-spin polarization decay are in good agreement with the experiment.

Photon echoes from (In,Ga)As quantum dots embedded in a Tamm-plasmon microcavity

We report on magnetic field-induced oscillations of the photon echo signal from negatively charged excitons in a CdTe/(Cd,Mg)Te semiconductor quantum well. The oscillatory signal is due to Larmor precession of the electron spin about a transverse magnetic field and depends sensitively on the polarization configuration of the exciting and refocusing pulses. The echo amplitude can be fully tuned from the maximum down to zero depending on the time delay between the two pulses and the magnetic-field strength. The results are explained in terms of the optical Bloch equations accounting for the spin level structure of electrons and trions.

Damping of Rabi oscillations in intensity-dependent photon echoes from exciton complexes in a CdTe/(Cd,Mg)Te single quantum well

We acknowledge the financial support by the Deutsche Forschungsgemeinschaft, Project ICRC TRR 160 and the Russian Foundation of Basic Research (RFBR) in the frame of the Project No. 15-52-12016 NNIO_a. The project SPANGL4Q acknowledges financial support from the Future and Emerging Technologies (FET) programme within the Seventh Framework Programme for Research of the European Commission, under FET-Open Grant No. FP7-284743. S.V.P. thanks the RFBR for partial financial support (Project No. 14-02-31735 mol_a). S.V.P. and I.A.Yu. acknowledge partial financial support from the Ministry of Education and Science of the Russian Federation (Grant No. 11.G34.31.0067) and St-Petersburg State University (SPbU) (Grant No. 11.38.213.2014). M.B. acknowledges support from the Ministry of Education and Science of the Russian Federation (Grant No. 14.Z50.31.0021).

Time-resolved photon echoes from donor-bound excitons in ZnO epitaxial layers

We report on the coherent optical response from an ensemble of (In,Ga)As quantum dots (QDs) embedded in a planar Tamm-plasmon microcavity with a quality factor of approximately 100. Significant enhancement of the light-matter interaction is demonstrated under selective laser excitation of those quantum dots which are in resonance with the cavity mode. The enhancement is manifested through Rabi oscillations of the photon echo, demonstrating coherent control of excitons with picosecond pulses at intensity levels more than an order of magnitude smaller as compared with bare quantum dots. The decay of the photon echo transients is weakly changed by the resonator, indicating a small decrease of the coherence time T2 which we attribute to the interaction with the electron plasma in the metal layer located close (40 nm) to the QD layer. Simultaneously we see a reduction of the population lifetime T1, inferred from the stimulated photon echo, due to an enhancement of the spontaneous emission by a factor of 2, which is attributed to the Purcell effect, while nonradiative processes are negligible, as confirmed from time-resolved photoluminescence.

Direct measurement of the long-range p−d exchange coupling in a ferromagnet-semiconductor Co/CdMgTe/CdTe quantum well hybrid structure

We study Rabi oscillations detected in the coherent optical response from various exciton complexes in a 20~nm-thick CdTe/(Cd,Mg)Te quantum well using time-resolved photon echoes. In order to evaluate the role of exciton localization and inhomogeneous broadening we use selective excitation with spectrally narrow ps-pulses. We demonstrate that the transient profile of the photon echo from the localized trion (X

Photon Echo from an Ensemble of (In,Ga)As Quantum Dots

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High-Resolution Two-Dimensional Optical Spectroscopy of Electron Spins

) and the donor-bound exciton (D

Access to long-term optical memories using photon echoes retrieved from electron spins in semiconductor quantum wells

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