Fig. 3.

Fluorescence intensities with the (a) milk-only target and (b) ICG–milk target. The abscissa is the SD distance, $\rho$, and the different colors indicate the different target depths, $Z_T=12$, 17, 22, and 27 mm (top layer thicknesses, $d=10$, 15, 20, and 25 mm). The fitting of Eq. (18) to the background intensities is shown by black solid curves. The fittings of Eq. (19) to the fluorescence intensities with the ICG–milk target are shown by colored solid curves in panel (b).