Fig. 2.

Depth profiles of the microsphere phantom at different focus depths (a) and with different concentrations (b). a) ${\text{μ}}_{\mathrm{s}}$ = 4.3mm⁻¹, the focus depths ${\mathrm{z}}_{\mathrm{f}}$ at 50 μm, 150 μm, 250 μm and 350 μm, respectively. b) ${\mathrm{z}}_{\mathrm{f}}$ = 150 μm, expected scattering coefficients are 10.7 mm⁻¹, 8.5 mm⁻¹, 6.4 mm⁻¹, 4.3 mm⁻¹, and 2.1 mm⁻¹, respectively. The dashed blue curves are averaged depth-profile from 5000 A-lines, and the solid black curves are the fitting functions.