Nonlinear optical response and exciton dephasing in quantum dots

Nonlinear optical response and exciton dephasing in quantum dots

The full time-dependent four-wave mixing polarization in quantum dots is microscopically calculated, taking into account acoustic phonon-assisted transitions between different exciton states of the dot. It is shown that quite different dephasing times of higher exciton states in pancake anisotropic InGaAs quantum dots are responsible for the experimentally observed [1] double-exponential decay ...

Exciton dephasing via phonon interactions in InAs quantum dots: Dependence on quantum confinement

We report systematic measurements of the dephasing of the excitonic ground-state transition in a series of InGaAs/GaAs quantum dots having different quantum confinement potentials. Using a highly sensitive fourwave mixing technique, we measure the polarization decay in the temperature range from 5 to 120 K on nine samples having the energy distance from the dot ground-state transition to the we...

Dephasing in Open Quantum Dots

Shape-averaged magnetoconductance (weak localization) is used for the first time to obtain the electron phase coherence time tf in open ballistic GaAs quantum dots. Values for tf in the range of temperature T from 0.34 to 4 K are found to be independent of dot area, and are not consistent with the tf ~ T22 behavior expected for isolated dots. Surprisingly, tfsT d agrees quantitatively with the ...

Exciton dephasing in ZnSe quantum wires

Spin-flip limited exciton dephasing in CdSe/ZnS colloidal quantum dots.

The dephasing time of the lowest bright exciton in CdSe/ZnS wurtzite quantum dots is measured from 5 to 170 K and compared with density dynamics within the exciton fine structure using a sensitive three-beam four-wave-mixing technique unaffected by spectral diffusion. Pure dephasing via acoustic phonons dominates the initial dynamics, followed by an exponential zero-phonon line dephasing of 109...