Femtosecond laser writing of silicon vacancy color centers with specific defect orientations in silicon carbide

To deterministically generate silicon vacancies (VSi) with high positioning accuracy and specific defect orientations is one of the outstanding challenges in the development of a new generation of quantum information technologies. Here, we firstly propose and experimentally demonstrate the laser writing method for the selective generation of silicon vacancy color centers with different defect orientations or types (V1 and V2). The results indicate that when processed at a wavelength of 1030 nm, an increased number of pulses significantly enhance the silicon vacancy color center yield, with a dominant presence of V1. In contrast, at a wavelength of 800 nm, high pulse energy (1000 nJ, corresponding to a specific power density of 4.917037 x 1018 W m-2) improves the generation probability ratio between V2 and V1 color centers, suggesting potential for selective enhancement. Based on simulation results and theoretical analysis, we attribute the generation probability of V1 and V2 centers to the different multi-photon absorption processes and defect ionization levels during femtosecond laser processing. These results highlight the facile optical fabrication of specific defect types for quantum technologies.