Figure 5. Ultrafast control of the SiV optical transition.

(a) Rabi oscillation with pulsed excitation. The photon counts (black) are recorded as a function of square root of power, the raw data are fitted using a sine function (red). (b) The photon count oscillates when the delay between two π/2 ps pulses varies by τ. Maximum and minimum value of the Ramsey oscillations can be extracted as shown by black and red dots. Blue curves represent the oscillation of the photon counts around delay τ with time shown stretched here for illustration. (c) Ramsey fringe visibility as a function of delay τ. An exponential decay fitting (red curve) yields T₂=780±141 ps.