March 2, 2020
Reproducibility of High-Performance Quantum Dot Single-Photon Sources
Single-photon sources based on semiconductor quantum dots have emerged as an excellent platform for high efficiency quantum light generation. However, scalability remains a challenge since quantum dots generally present inhomogeneous characteristics. Here we benchmark the performance of 15 deterministically fabricated single-photon sources. They display an average single-photon purity of 95.4% ± 1.5% with an average mean wavepacket overlap of 88.0% ± 3.1% corresponding to a single-photon indistinguishability of 92.2% ± 2.6% and high homogeneity in operation wavelength and temporal profile. Each source also has state-of-the-art brightness with an average first lens brightness value of 13.6% ± 4.4%. While the highest brightness is obtained with charged quantum dots, the highest quantum purity is obtained with neutral ones. We also introduce various techniques to identify the nature of the emitting state. Our study sets the groundwork for large-scale fabrication of identical sources.
November 27, 2019
Interfacing scalable photonic platforms: solid-state based multi-photon interference in a reconfigurable glass chip
Scaling-up optical quantum technologies requires a combination of highly efficient multi-photon sources and integrated waveguide components. Here, we interface these scalable platforms, demonstrating high-rate three-photon interference with a quantum dot based multi-photon source and a reconfigurable photonic chip on glass. We actively demultiplex the temporal train of single photons obtained from a quantum emitter to generate a 3.8×103 s−1three-photon source, which is then sent to the input of a tunable tritter circuit, demonstrating the on-chip quantum interference of three indistinguishable single photons. We show via pseudo number-resolving photon detection characterizing the output distribution that this first combination of scalable sources and reconfigurable photonic circuits compares favorably in performance with respect to previous implementations. Our detailed loss-budget shows that merging solid-state multi-photon sources and reconfigurable photonic chips could allow 10-photon experiments on chip at ∼40 s−1 rate in a foreseeable future.
August 19, 2019
Generation of non-classical light in a photon-number superposition
Generating light in a pure quantum state is essential for advancing optical quantum technologies. However, controlling its photon number remains elusive. Optical fields with zero and one photon can be produced by single atoms, but, so far, this has been limited to generating incoherent mixtures or coherent superpositions with a very small one-photon term. Here, we report the on-demand generation of quantum superpositions of zero, one and two photons via coherent control of an artificial atom. Driving the system up to full atomic inversion leads to quantum superpositions of vacuum and one photon, with their relative populations controlled by the driving laser intensity. A stronger driving of the system, with 2π pulses, results in a coherent superposition of vacuum, one and two photons, with the two-photon term exceeding the one-photon component, a state allowing phase super-resolving interferometry. Our results open new paths for optical quantum technologies with access to the photon-number degree of freedom.
November 21, 2019
June 4 2019
October 14, 2019
April 29, 2019