Direct observation of stimulated emission of NV– centers in synthetic HPHT diamond

Data on direct observation of stimulated emission of $\mathrm{NV}^{-}$centres in synthetic NRNT-diamonds located in a focused pump beam are presented. The spectra and pulse durations of the stimulated emission were simultaneously recorded. It was found that the shapes of the spectra and the intensity of stimulated emission depend on the number of emitting centres and the position of the crystal relative to the focus of the pump beam.