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Physics Seminar

Exciting all exciton states in a quantum dot under the influence of phonons

Speaker: Jun-.Prof. Doris Reiter (Münster University)
Date: Wednesday 20 February 2019
Time: 15:00
Venue: Queens Buildings N/4.07

Semiconductor quantum dots are quasi-zero-dimensional structures, in which electrons are confined on the nanoscale. A discrete energy spectrum emerges, hence quantum dots are nicknamed artificial atoms. Using laser pulses electron-hole pairs, the so-called excitons, can be created and manipulated in the quantum dot. This is the foundation to use semiconductor quantum dots for applications in quantum information technology, e.g., as source for single or entangled photons. In my talk I will discuss the optical state preparation using chirped laser pulses. A chirped laser pulse changes its frequency during the pulse, which leads to the effect of adiabatic rapid passage yielding a robust population of the exciton. This versatile method can also be extended to excite the biexciton as well as the dark exciton by adding a tilted magnetic field. I will present how all exciton complexes can be prepared. Further, I will address the interaction with phonons, which can result into a damping of the adiabatic rapid passage effect for certain excitation parameters, and compare our theoretical predictions with recent experimental measurements. CV: The research interests of Doris Reiter are optically induced quantum dynamics in nanostructured solids. Doris Reiter has studied at the University of Münster, where she also did her PhD in 2010. During her PhD studies she spend half a year in Toronto in the group of John Sipe. During her PostDoc stage she was one year at Imperial College London in the group of Ortwin Hess with a DAAD P.R.I.M.E. scholarship. Since 2016 Doris holds a Junior-Professor position at the University of Münster with her own group.