Resonance light scattering by optical phonons in diamond crystal with nitogen-vacancy centres

Observation of the resonance enhancement of the intensity of light scattering by optical phonons in a diamond crystal with nitogen-vacancy centres is reported. It is established that the unusual resonance with electronic transitions for optically active nitrogen impurities with both zero-phonon-lines plays the determining role in the increase in intensity of such scattering: at 575.468 nm for a neutral NV$^{0}$ center and at 637.874 nm for a negatively charged NV$^{-}$-center. The obtained experimental data indicate the detection of a strong resonant-intensity amplification in the input scattering channel for the NV$^{0}$ center and in the output channel for the NV$^{-}$-center.