Laser Written Diamond Optoelectronic Devices for use in Quantum Computing*

The nitrogen-vacancy (NV) defect within a diamond lattice has been shown as a viable candidate for a quantum register. Using laser writing, these defect centres can be placed with high precision at any depth through a sample, without inducing significant damage to the surrounding lattice [1-3], to create deep solid state qubit arrays. These sites have shown coherence times of 700 µs, as long as the longest achieved for room-temperature spin-echo coherence measurements in non-¹²C enriched diamond [1]. Additionally, the technique can be used to create conductive graphitic tracks, which are the subject of current investigation for their potential to act as DC circuitry within the diamond. Configuring the wires such that NVs lie between ends of two wires may allow charge state transfer, bringing greater control of defects, and enable sites to be tuned precisely. It is hoped that, combining these aspects, a single diamond could hold many individually addressable qubits leading to a compact quantum processor.

[1] C.J. Stephen et al., arXiv:1807.03643 (2018)
[2] Y.-C. Chen et al., Nature Photonics 11, 77 (2017)
[3] Y.-C. Chen et al., arXiv:1807.04028 (2018)