On-demand semiconductor single-photon source with near-unity indistinguishability

Abstract

Single photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness, and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence (RF) has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed RF single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3-ps laser pulses. The π-pulse excited RF photons have less than 0.3% background contributions and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.

Combining in-situ lithography with 3D printed solid immersion lenses for single quantum dot spectroscopy

“…Recently, several independent demonstrations of near-unity indistinguishability2345 have been published, showing that this technology is mature for quantum information purposes. As the QDs are embedded into a solid-state matrix, the amount of light that can be extracted is severely limited by the total internal reflection (TIR) due to the high semiconductor-to-air refractive index contrast.…”

Advances in Mid-Infrared Spectroscopy for Chemical Analysis

“…On-chip waveguide integrated QDs (58), on the other hand, are more suitable for on-chip integrated photonic circuits, as light-generation structures are directly integrated into the waveguide, thereby facilitating, for example, single photon sources for quantum computing and quantum sensing applications (59,60). However, operation at room temperature and electronic pumping remain challenging for such devices.…”

Quantum dots for quantum information

“…This means that phonons are not excited in the QD and the antibunched light arising shows very high indistinguishability. Record indistinguishability single photon sources [16] and entangled photon sources [17] have been produced using this technique.…”