Spectral Monitoring During Laser Processing for Activation of Single Group-IV Colour Centres in Diamond

Laser processing with ultrashort pulses has previously been demonstrated as a useful mechanism for ultra-high precision fabrication of colour centre defects, such as the nitrogen vacancy in diamond ^1,2. Recently spin-photon interfaces based on different colour centres in diamond, such as those involving group IV atoms, have been shown to offer particular benefits for future quantum networks³. However, new techniques for precise single-defect positioning and activation is critical for scalable device fabrication. Here we address this problem by demonstrating a two-step fabrication method for tin vacancy (SnV-) centres that uses site-controlled ion implantation followed by local femtosecond laser annealing with in-situ spectral monitoring⁴.