Institut des
NanoSciences de Paris
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Single and indistinguishable photon sources based on semiconductor quantum dots

(Paola Atkinson, Richard Hostein, Valia Voliotis)

Semiconductor quantum dots (QD) are ideal solid-state systems for realizing efficient and bright single photon sources. By performing photon correlation measurements the generation of non-classical states of light can be shown [1]. Moreover, the degree of indistinguishability of the emitted photons can be measured by Hong-Ou-Mandel two-photon interference experiments. For resonant excitation, the indistinguishability that reaches 80%, remains constant at low temperature and then rapidly drops above 10K. On the basis of these experiments and a theoretical model, we have attributed this behavior to the interaction of the QD with the acoustic phonons bath. This coupling is the dominant mechanism of dephasing and constitutes an intrinsic limitation to the coherence properties of this kind of solid system [2].

[1] L. Monniello, A. Reigue, R. Hostein, A. Lemaitre, A. Martinez, R. Grousson, V. Voliotis, Indistinguishable single photons generated by a quantum dot under resonant excitation observable without postselection, Phys. Rev. B 90, 041303(R) (2014)

[2] A. Reigue, F. Lux, L. Monniello, M. Bernard, F. Margaillan, A. Lemaître, J.Iles-Smith, J. Mork, R. Hostein, and V. Voliotis, Probing exciton-photon interaction by two-photon interferences in a resonantly driven quantum dot, Phys. Rev. Lett. 118, 233602 (2017)

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Caption : SEM Image (C2N) showing a one-dimensional waveguide etched on the surface of the sample containing a layer of QDs embedded in Bragg mirrors. The dots are represented in yellow. The resonant laser is guided along the ridge and the emitted photons are detected from the top surface. In the center, a coincidence histogram of the detected photons in an HBT setup shows a strong antibunching at zero delay, demonstrating the single photon emission. Right : the degree of indistinguishability measured in a two-photon interference setup reaches 80% at low temperature and is limited by the coupling to acoustic phonons when the temperature is increased.