Single artificial atoms in silicon emitting at telecom wavelengths

Carbon-related point defects can be isolated in a commercial silicon-on-insulator wafer, acting as artificial atoms that provide efficient polarized single-photon emission at wavelengths suitable for long-distance propagation in optical fibres. 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. Here we report 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. Our results show 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.