Scalable integrated single-photon source

The team behind the new discovery from Niels Bohr Institute in Copenhagen, Denmark. Credit: Niels Bohr Institute

Photonic qubits are key enablers for quantum information processing deployable across a distributed quantum network. An on-demand and truly scalable source of indistinguishable single photons is the essential component enabling high-fidelity photonic quantum operations. A main challenge is to overcome noise and decoherence processes to reach the steep benchmarks on generation efficiency and photon indistinguishability required for scaling up the source.

A team at Niels Bohr Institute in Denmark has reported on the realization of a deterministic single-photon source featuring near-unity indistinguishability using a quantum dot in an “on-chip” planar nanophotonic waveguide circuit.

The device produces long strings of >100 single photons without any observable decrease in the mutual indistinguishability between photons. A total generation rate of 122 million photons per second is achieved, corresponding to an on-chip source efficiency of 84%.

These specifications of the single-photon source are benchmarked for boson sampling and found to enable scaling into the regime of quantum advantage.

The paper has been published in Science Advances.