Figure 3.

Detection of charge dynamics. (a) Pulse sequence adopted to investigate charge dynamics under laser pumping, for variable irradiation pulse length τ_L. Laser-induced NV⁰ → NV^– photoconversion results in a decrease of the NV⁰ signal and an increase of the NV^–. As an example, panel (b) shows the decrease in NV⁰ FL for sample F2, as measured in the 550–600 nm window, for different laser powers. (c) Pulse sequence used to detect the charge recovery in the dark after a preparation pulse. Recovery of NV⁰ FL for sample F2 at a laser power of 625 mW is shown in panel (d). Various curves in panel (d) correspond to different durations of the initialization pulse.