  Optically-active spin qubits in wide-bandgap semiconductors exist in several
charge states, though typically only specific charge states exhibit desirable
spin or photonic properties. An understanding of how interconversion between
different charge states occurs is important for most applications seeking to
employ such defects in quantum sensing and information processing, and
additionally serves as a means of testing and verifying models of the defect
electronic structure. Here, we use charge-sensitive confocal imaging to study
the wavelength dependence of optical carrier generation in diamonds hosting
nitrogen-vacancy (NV) centers, silicon vacancy (SiV) centers and substitutional
nitrogen (N). We study the generation of distinctive charge-capture patterns
formed when photogenerated charge carriers are captured by photoluminescent
defects, using light spanning 405-633\,nm (1.96-3.06\,eV). We observe distinct
regimes where one- or two-photon ionization or recombination processes
dominate, and a third regime where anti-Stokes mediated recombination drives
weak NV charge cycling with red light. We then compare red-induced charge
cycling to fast charge carrier transport between isolated single NV centers
driven with green and blue light. This work reports new optically-mediated
charge cycling processes of the NV centers, and has consequences for schemes
using charge transfer to identify non-luminescent defects and photoelectric
detection, where ambiguity exists as to the source of photocurrent.
