Photophysics of Boron Vacancy Centers in Neutron Irradiated Flakes of Hexagonal Boron Nitride

Defects in wide bandgap materials have provided a robust platform for hosting single quantum emitters, which are a fundamental component in the development of quantum technologies. Recently, defects in 2D materials, such as hexagonal boron nitride (hBN), have become the focus of research owing to their potential to overcome some of the limitations of defects in diamond, such as nitrogen vacancy (NV) centers. Specifically, the potential for hBN defects to exist on or very close to the surface of the material, thereby reducing the standoff distance when used as a quantum sensor. Boron vacancy centers (V_B^–) in hBN have a similar electronic structure to NV centers, with a ground state spin triplet and zero-field splitting of approximately 3.45 GHz. However, many of the V_B^– decay rates from the excited state are still largely unknown. In this poster, we present time resolved measurements of neutron irradiated flakes of hBN containing V_B^–. We report measurements of the intersystem crossing lifetime for different flake sizes, utilizing the photoluminescence recovery method, which was previously used in NV metastable lifetime measurements. Additionally, we prepare an ensemble of V_B^– in a thermal and polarized distribution and show the response as a function of excitation power. Lastly, we repeat these measurements with 473 nm excitation and compare with 515 nm excitation.