Fig. 1. Skin stratification model

Fig. 2. Absorption coefficient of Hb， HbO₂ and H₂O

Fig. 3. Relationship between absorption coefficient and wavelength

Fig. 4. Relationship between reduced scattering coefficient and wavelength

Fig. 5. Monte Carlo simulation process

Fig. 6. Photon coordinate initialization

Fig. 7. Penetration of three wavelengths

Fig. 8. Depth of light penetrating the skin

Fig. 9. Photon deposition rate distribution

Fig. 10. Actual optical path diagram

Fig. 11. Schematic diagram of different beam incidence

Fig. 12. Divergent light incidence diagram

Fig. 13. Comparison of penetration depth of four skin model

Fig. 14. Comparison of penetration depth with different divergence angles

Fig. 15. Comparison of relative photon injection rate of target with different divergence angles

Fig. 16. Comparison of relative injection rate of each layer