Figure 3: Relative multi-photon coherence times.
From: Observation of detection-dependent multi-photon coherence times
Relative coherence times as a function of the number of photons, quantified by width ratios σ(N−m,m)/σ(1,1), are shown for photons with Gaussian frequency distribution (equation 9). Circles (red), diamonds (green), squares (black) and triangles (brown) represent the width ratios for the detection of (N,0), (N/2,N/2), (N/2+1,N/2−1) and (N/2+2,N/2−2), respectively. The dashed (red) line is the asymptotic expression 
for the width ratio of the (N,0)-signal.
