Fig. 3: Pump-probe modulation of the photon number distribution induced by the coherent phonon excitation.

a Phase-averaged quadrature distribution for a probe pulse with a mean photon number of 13.8 photons per pulse. Left: histogram of the equilibrium phase-averaged quadrature distribution. Right: histogram map describing the time-resolved dynamics of the quadrature distribution. b Applying the tomography algorithm to the quadrature data we study the evolution of the photon number distribution. Equilibrium (left) and time-resolved evolution (right) are shown. We also consider a weaker probe beam with an average of 2.9 photons per pulse and report the relative evolution for the quadrature (c) and photon number (d) distributions. We observe in both cases the presence of coherent oscillations at the phonon frequency