Figure 4 | Scientific Reports

Figure 4

From: All-optical charging and charge transport in quantum dots

Figure 4

Coherent and incoherent charge transfer. (a) \(\Lambda\)-type system formed by two location states of an electron, \(|{e}_{L}\rangle\) and \(|{e}_{R}\rangle\), and a spatially distributed negatively charged exciton state, \(|{X}^{-}\rangle\). Driving transition \(|{e}_{L}\rangle \leftrightarrow |{X}^{-}\rangle\) with a single resonant pump, \({\Omega }_{1}\ne 0\), \({\Omega }_{2}=0\), incoherently pumps the electron to state \(|{e}_{R}\rangle\) due to the spontaneous recombination of the left electron with the hole, \(|{X}^{-}\rangle \to |{e}_{R}\rangle\). Coherent charge transfer can be obtained, e.g. using the STIRAP scheme, when both transitions are driven, \({\Omega }_{1}\ne 0\), \({\Omega }_{2}\ne 0\) in a suitable pulse sequence (see Supplementary Section S4). (b) Fidelities of coherent and incoherent transfers plotted against transfer times, for a structure of dimension \([{d}_{1},{d}_{2}, {d}_{3}] =[10\;\mathrm{nm},10\;\mathrm{nm},7\;\mathrm{nm}]\) for which \({1/\gamma }_{1}=44\;\mathrm{ns}\) and \({1/\gamma }_{2}=22\;\mathrm{ns}.\)

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