Fig. 4
From: Direct observation of broadband nonclassical states in a room-temperature light–matter interface
Nonclassicality excitation tradeoff. Experimental results on excitation probability of photon pairs (a) and cross-correlation function \(g_{\mathrm {{SI}}}^{(2)}\) (b) with scanned pulse energy of the coupling light. The detuning is set at Δ1 + Δ2 = 2π × 4 GHz. The results \(g_{\mathrm {{SI}}}^{(2)}\) larger than 2 (green dashed) is in nonclassical regime. The beam waist of the coupling light is 90 μm. The coincidence window (also known as integration gate) is 9 ns and is centered at the arrival time of the desired photons. Error bars are given by Poissonian statistics
