Fluorescence modulation of the nitrogen-vacancy center with competition between charge-state conversion and stimulated emission

Abstract

The nitrogen-vacancy (NV) center in diamond has been widely used for quantum information processing, nanophotonics, and biological imaging. In this work, we experimentally studied the charge-state conversion and stimulated emission of the NV center with a near-infrared (NIR) pumping laser. The competition between these two processes resulted in a nonmonotonic dependence of the NV center’s fluorescence intensity on the NIR laser power. Fluorescence enhancement was observed with a weak NIR laser, while fluorescence depletion was observed with a high-power NIR laser. It led to the nonmonotonic change of the spatial resolution with stimulated emission depletion microscopy, which has been used for subdiffraction imaging of the NV center. Our work can help to further understand the optical mechanism and extend the applications of the NV center.