Physical Review Letters
Optimum Photoluminescence Excitation and Recharging Cycle of Single Nitrogen-Vacancy Centers in Ultrapure Diamond
Katja Beha, Anton Batalov, Neil B. Manson, Rudolf Bratschitsch, Alfred Leitenstorfer
Abstract
Important features in the spectral and temporal photoluminescence excitation of single nitrogen-vacancy (NV) centers in diamond are reported at conditions relevant for quantum applications. Bidirectional switching occurs between the neutral (${\mathrm{NV}}^{0}$) and negatively charged (${\mathrm{NV}}^{\ensuremath{-}}$) states. Luminescence of ${\mathrm{NV}}^{\ensuremath{-}}$ is most efficiently triggered at a wavelength of 575 nm which ensures optimum excitation and recharging of ${\mathrm{NV}}^{0}$. The dark state of ${\mathrm{NV}}^{\ensuremath{-}}$ is identified as ${\mathrm{NV}}^{0}$. A narrow resonance is observed in the excitation spectra at 521 nm, which mediates efficient conversion to ${\mathrm{NV}}^{0}$.