Fig. 1. (a)—(f) represent the different decayed teeth

Fig. 2. The schematic of experimental device

Fig. 3. The degree of polarization parameter characterization of different decay teeth sample
(a)—(d) data at the wavelength of 450, 550, 670, 860 nm, respectively

Fig. 4. The contrast figure of the model simulated results and measured data
(a)—(d) corresponding the wavelength of 450, 550, 670, 860 nm