(color online) Coherent manipulation and characterization of a single NV electron spin. (a) Pulse sequence. The first green laser polarize the electron spin to the state, then resonant microwave (MW) pulses are applied to drive the coherent evolution of the electron spin. After manipulation, the spin state is readout by counting the fluorescence intensity. (b) Rabi oscillation of the NV electron spin under resonant driving. The signal is measured with pulse sequence in panel (a). (c) Ramsey fringes (FID) of the NV electron spin. The fast modulation is caused by the host ¹⁴N nuclear spin and the slow modulation is caused by a ¹³C nuclear spin. (d) Spin echo (Hahn echo) of the NV electron spin. The collapse and revival behavior is caused by the Larmor precession of its surrounding ¹³C nuclear spins. Inset of panels (c) and (d): the used pulse sequence.