Single artificial atoms in silicon emitting at telecom wavelengths

The experimental setup used by the researchers to detect single fluorescent artificial atoms in silicon. A green laser is used to excite a silicon-on-insulator sample located inside the vacuum chamber of a He-closed cryostat. The photoluminescence emitted by the sample is collected and sent towards near-infrared single-photon detectors. Credits: A. Dréau/A. Durand/ P. Valvin (Laboratoire Charles Coulomb, CNRS & University of Montpellier, France).

Researchers at Université de Montpellier and CNRS, University Leipzig and other universities in Europe have recently successfully isolated single, optically active artificial atoms in silicon for the first time.

Given its potential for integration and scalability, silicon is likely to be a key platform for large-scale quantum technologies. Individual electron-encoded artificial atoms, formed by either impurities or quantum dots, have emerged as a promising solution for silicon-based integrated quantum circuits.

However, single qubits featuring an optical interface, which is needed for long-distance exchange of information, have not yet been isolated in silicon.

The team has reported the isolation of single optically active point defects in a commercial silicon-on-insulator wafer implanted with carbon atoms. These artificial atoms exhibit a bright, linearly polarized single-photon emission with a quantum efficiency of the order of unity. This single-photon emission occurs at telecom wavelengths suitable for long-distance propagation in optical fibres.

Their results showed that silicon can accommodate single isolated optical point defects like in wide-bandgap semiconductors, despite a small bandgap (1.1 eV) that is unfavourable for such observations.

Their paper has been published in Nature Electronics.

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