Pure dephasing in the linear and nonlinear optical response of quantum dots

W. Ben Chouikha, S. Jaziri, R. Bennaceur

Gustavo Diniz, Silvio Quintino, V. V. França

N. H. Bonadeo, Gang Chen, D. Gammon +1 more

We report a study of the coherent nonlinear optical response of individual excitons localized in GaAs quantum dots. Our data show that the nonlinear response is comprised of an incoherent contribution dominated by saturation of the oscillator strength and a coherent contribution giving rise to population pulsations. The results compare well with present theory and show the similarities with atoms and quantum dots in their coherent optical interaction with light. The measured energy relaxation and dephasing rates are comparable, reflecting the absence of significant pure dephasing at low temperatures. In addition, we use nonlinear spectroscopy to investigate quantum dot coupling showing the presence of an incoherent coupling leading to fast energy relaxation. The polarization properties as well as the fine structure splitting are also discussed.

N. H. Bonadeo, Duncan G. Steel, D. Gammon

Victor Bondarenko, Yang Zhao

N. H. Bonadeo, Gang Chen, Dan Gammon +3 more

Coherent nonlinear optical spectroscopy of individual excitons in GaAs quantum dots is demonstrated and shows strong similarities with atoms in their coherent optical interaction, unlike higher dimensional heterostructures. The nonlinear response is dominated by an incoherent contribution (saturation) and a coherent contribution (population pulsations) of the single dot and compares well with present theory. The data shows that energy relaxation and dephasing rates are comparable, reflecting the absence of significant pure dephasing, and also demonstrate the presence of interdot energy transfer.