Title：Resonance fluorescence from semiconductor quantum emitters

Speaker：Disheng Chen，Nanyang Technological University

Date：July 8, 2020 9:30 AM

Meeting Link：Tecent Meeting

https://meeting.tencent.com/s/1eEQyfkawZ7g

Meeting ID: 968 203 655

Abstract：Solid-state quantum bits and the associated single-photon emitters possess unparalleled advantages over the atomic systems regarding the integration, scalability and easiness of operations by sacrificing some extent of cleanness in the host environment. Resonance fluorescence (RF) scattered by these artificial atoms is of paramount importance for applications pivoted on two-photon interference, such as distributed optical quantum computing and large-scale quantum networks. However, many solid-state emitters suffer from large inhomogeneous broadening, photoluminescence blinking and even a complete quenching of RF. Quite often, these phenomena are attributed to the uncontrolled local Fermi-level pinning or fluctuations due to the low but non-negligible background doping of the host materials, for example, nitrogen, boron in diamond, and carbon, silicon in GaAs.

In this talk, I will discuss an all-optical method to modify the local Fermi level around a Germanium-vacancy (GeV) color center in diamond thus recovering the RF by an enhancement factor of hundreds. Meanwhile, the challenges posed by the spectral diffusion caused by environmental fluctuations and energy mismatch among different quantum emitters can be efficiently reconciled by employing coherent scattering. With a proper fine-structure splitting, a 3-level V-system (InGaAs/GaAs quantum dots) can outperform the conventional 2-level system on coherent scattering intensity and purity. This provides a unique opportunity for multi-level systems to play an important role in quantum optics.