Electron spin studies of nitrogen vacancy centers in nanodiamonds

Fluorescent nanodiamonds containing nitrogen vacancy centers are created by electron irradiation. The values of spin echo coherence time T-2 of nitrogen vacancy centers in nanodiamonds are very small, which are between 0.86 mu s and 5.6 mu s. The results of Ramsey interference fringes show that the values of dephasing time T-2* differ from each other and the T-2* of nitrogen vacancy center NV1 is biggest (0.7 mu s). Its inhomogeneous linewidth obtained from Fourier transform frequency spectrum of Ramsey interference fringes is 1.05 MHz. The hyperfine structure for the nitrogen vacancy center electron spin coupled to the host nitrogen-14 nuclear spin can be detected by the electron spin resonance spectrum in nitrogen vacancy center NV1. It is important for the realization of the manipulation of nuclear spins and quantum gates of multiqubit in nanodiamonds.