Electron spin echoes were performed on nitrogen-vacancy $(\mathrm{N}-V)$ 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 $3.6\hspace{0.5em}\mu \mathrm{s}$ was measured, and coupling of the electronic spin to the ${}^{14}\mathrm{N}$ nuclear spin was observed. Because of the favorable properties of the $\mathrm{N}-V$ center, interesting extensions of these single-qubit operations can be proposed.

• Received 9 March 2001

DOI:https://doi.org/10.1103/PhysRevB.64.041201