Figure 4:

2-pulse illumination modulation across the entire field of view enables wide-field quasi $g_2(\tau )$ measurement and correlation time mapping. a-d The quasi $g_2(\tau )$, i.e. $K_{2P}^2(T)$ images at $T=10\mu \mathrm{s},15\mu \mathrm{s},40\mu \mathrm{s}$ and $100\mu \mathrm{s}$, respectively. Image size: 1000×750. e-f ICT maps extracted with three $g_1(\tau )=e^{-{\left(\tau /{\tau }_c\right)}^n}$ models. $n=2,1$ and 0.5, respectively. $\mathrm{I}\mathrm{C}\mathrm{T}=1/{\tau }_c$. The 2D map of correlation times was obtained by fitting $K_{2P}^2(T)$ maps at 15 $T$ time points ranging from $10\mu \mathrm{s}$ to 5 ms. h ICT map with $n$ optimized at each pixel to maximize the $R^2$, the coefficient of determination. i Map of optimal $n$. j-l Fitting results of $K_{2P}^2(T)$ at the three points highlighted in i. lg: logarithm to base 10. In figure j, the $n=1$ and $n=0.5g_1(\tau )$ models fail to fit the $K_{2P}^2(T)$ curve. Hence, they appear as a flat line in the plot. The same is true for the $n=0.5g_1(\tau )$ model in figure k.