The ability to generate light in pure quantum states is central to the development of quantum-enhanced technologies. Recently, artificial atoms in the form of semiconductor quantum dots have emerged as an excellent platform for quantum light generation [1]. By placing the quantum dot in an optical microcavity, pure dephasing phenomena are strongly suppressed and single photon wavepackets with very high quantum purity in the frequency domain are generated [2]. This is obtained at high efficiency, which opens new possibilities for optical quantum protocols such as the resource efficient generation of linear cluster states [3].

We recently benchmarked our technology to study the performance reproducibility [4] and explored new schemes to push further the source efficiency [5]. Interestingly, this last study shows that we can turn the emitter imperfections and its coupling the solid-state environment into resources.

 

Finally, this excellent artificial atom-photon interface allows us to investigate fundamental quantum optics. We recently demonstrated that the coherence imprinted at the atomic level can be transferred to the radiated field through spontaneous emission. We observe for the first time the direct generation of light pulses in a pure quantum superposition of vacuum and one-photon with a full control of their relative populations and phase [6].

 

[1] P Senellart, G Solomon, A White, Nature Nanotechnology 12 (11), (2017)

[2] N. Somaschi, et al. Nature Photonics, 10, 340 (2016)

[3] D. Istrati et al. Nature Communications 11, 5501 (2020)

[4] H. Ollivier et al, ACS Photonics 7, 1050 (2020)

[5] S. Thomas et al. arXiv:2007.04330

[6] J. C. Loredo, C. Anton, et. al, Nature Photonics 13, 803 (2019)

 

https://bristol-ac-uk.zoom.us/j/95982115892