Fig. 5.

(a) Sensitivity curves plotted as a function of $T/{\tau }_c$, indicating that speckle contrast ($\kappa (T)$) has a maximum sensitivity, when $T={\tau }_c$ ; The range “D” indicates the region of data ($\kappa (T)$), where $T\ge {\tau }_c$. (b) Speckle contrast data plotted against exposure time, where highlighted region shows speckle contrast for T which belongs to region D. Here ${\kappa }_1^2$ and ${\kappa }_2^2$ corresponds to ${\tau }_c$ values of ${10}^{-3}\mathrm{s}$ and ${10}^{-1}\mathrm{s}$ respectively.