Photochromism in single N-vacancy optical centers in diamond was demonstrated. Time-resolved optical spectroscopy showed that intense irradiation at 514nm switches the N-vacancy defects to the negative form. This defect state relaxes back to the neutral form under dark conditions. Temporal anticorrelation of photons emitted by the different charge states of the optical center unambiguously indicated that the N-vacancy defect accounts for both 575 and 638nm emission bands. Possible mechanism of photochromism involving N donors was discussed.

Photochromism in Single Nitrogen-Vacancy Defect in Diamond. T.Gaebel, M.Domhan, C.Wittmann, I.Popa, F.Jelezko, J.Rabeau, A.Greentree, S.Prawer, E.Trajkov, P.R.Hemmer, J.Wrachtrup: Applied Physics B, 2006, 82[2], 243-46