We describe an all-optical scheme for spin manipulation in the ground-state triplet of the negatively charged nitrogen-vacancy (NV) center in diamond. Virtual optical excitation from the
3A2 ground state into the
3E excited state allows for spin rotations by virtue of the spin-spin interaction in the two-fold orbitally degenerate excited state. We derive an effective Hamiltonian for optically induced spin-flip transitions within the ground state spin triplet due to off-resonant optical pumping. Furthermore, we investigate the spin qubit formed by the Zeeman sublevels with spin projection
mS=0 and ${m}_{S}=\ensuremath{-}1$ along the NV axis around the ground state level anticrossing with regard to full optical control of the electron spin.
Electron spin echoes were performed on nitrogen-vacancy $(\mathrm{N}\ensuremath{-}V)$ centers in diamond using optical polarization and detection and 35 GHz microwave control. The experiments demonstrate an approach to quantum information in the solid state. A phase memory time of $3.6 \ensuremath{\mu}\mathrm{s}$ was measured, and coupling of the electronic spin to the
14N nuclear spin was observed. Because of the favorable properties of the $\mathrm{N}\ensuremath{-}V$ center, interesting extensions of these single-qubit operations can be proposed.