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Controlling the Biexciton-Exciton Cascade Kinetics in a Quantum Dot via Coupling to a Microcavity Optical Mode

100%

Sęk G., Krizhanovskii D., Kulakovskii V., Reitzenstein S., Kamp M.

Acta Physica Polonica A

2016

vol. 129

issue 1a

A-44-A-47

The luminescence of single and two exciton states in a quantum dot embedded in the active layer of a micropillar cavity has been investigated. Temperature tuning has been used to bring the energy states of the quantum dot and the cavity into resonance. Studying the resonance behavior of the exciton and biexciton transitions with cavity mode revealed a similar Purcell effect for both lines. The cavity-induced changes of the respective radiative lifetimes have been shown to allow for controlling the ratio between the single and two exciton occupation and their relative emission rates in a single quantum dot.

Nano-Optics on Individual Quantum Objects - From Single to Coupled Semiconductor Quantum Dots

73%

Bacher G., Schömig H., Welsch M., Scheibner M., Seufert J., Obert M., Forchel A., Maksimov A., Zaitsev S., Kulakovskii V.

Acta Physica Polonica A

2002

vol. 102

issue 4-5

475-494

Some recent highlights of our optical studies on single and coupled semiconductor quantum dots are reviewed. In the first part, we concentrate on the role of spins and spin-spin interaction in nonmagnetic and magnetic single quantum dots. In the case of strictly resonant excitation of the ground state in self-assembled CdSe/ZnSe quantum dots, we find an exciton spin relaxation time, which exceeds the recombination lifetime significantly. Linear polarization has to be used for these experiments, as the electron-hole exchange interaction lifts the spin degeneracy and the eigenstates are linear combinations of spin-up and spin-down excitons. In a magnetic quantum dot, the exchange interaction between carrier spins and the spins of magnetic ions is shown to be responsible for giant magneto-optical effects. We demonstrate the formation of zero-dimensional magnetic polarons and we succeeded in measuring the magnetization on a scale of a few nanometers using the characteristic photoluminescence signal of individual quantum dots as experimental monitor. The second part is devoted to pairs of single quantum dots. On one hand, single exciton tunneling within an individual quantum dot pair is demonstrated studying single pairs of vertically correlated strain-induced and self-organized quantum dots. On the other hand, we show that in a pair of lithographically defined single dots with strongly different g-factors the energy spacing between the dot ground states can be tuned in an external magnetic field by about 10 meV, giving access to a controlled coupling between two individual quantum dots.

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2 Acta Physica Polonica A

1 2016

1 2002

2 Kulakovskii V.

1 Bacher G.

1 Forchel A.

1 Kamp M.

1 Krizhanovskii D.

1 Maksimov A.

1 Obert M.

1 Reitzenstein S.

1 Scheibner M.

1 Schömig H.

1 Seufert J.

1 Sęk G.

1 Welsch M.

1 Zaitsev S.

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Controlling the Biexciton-Exciton Cascade Kinetics in a Quantum Dot via Coupling to a Microcavity Optical Mode

Nano-Optics on Individual Quantum Objects - From Single to Coupled Semiconductor Quantum Dots