*3.1. Validation Results of Optical Properties*

The system in Figure 2a shows the curves of μ*<sup>a</sup>* of water obtained by AIS and μ*<sup>a</sup>* reported by Deng et al. [39]. The results are in agreement with previous reports, which find that there are three absorption peaks at 1485, 1169 and 980 nm. In addition, the relative error of μ*<sup>a</sup>* values at 905–1600 nm ranged from 0.03% to 10.25%. Figure 2b presents the curve of μ- *s* values of 1% Intralipid based on AIS. A comparison of the measured μ- *s* and reference value based on Mie theory revealed that both profiles showed a downward trend with the increase in wavelengths [38], and the mean relative error was 9.20%. However, the relative error of μ*<sup>a</sup>* and μ- *<sup>s</sup>* after 1600 nm clearly increases. This is due to a low signal-to-noise ratio of the spectrometer, or more detected interference signals. Therefore, μ*<sup>a</sup>* and μ- *s* at 905–1600 nm were taken as the effective data in this study.

**Figure 2.** Absorption (μ*a*) estimation on water (**a**) and scattering (μ- *s*) estimation on 1% Intralipid (**b**).
