Study on the Impact of Size Factor and Relative Refractive Index on the Asymmetry Factor

The scattering phase function is one of the most important parameter to describe the transfer of laser energy in various biological tissues. However, the scattering phase function, expressed by Henyey-Greenstein function, is extremely depended on the asymmetry factor. A quantitative relationship between the asymmetry factor ,the size factor and relative refractive index is helpful to determine the corresponding scattering phase function. To obtain this quantitative relationship, by utilizing Mie scattering theory, a numerical calculation of the asymmetry factor involved in the Henyey -Greenstein phase function is carried out at first, and then the relationship between the asymmetry factor,the size factor and relative refractive index is analyzed. Based on these discussions, a new function revealed the quantitative relationship between the asymmetry factor ,the size factor and relative refractive index of tissue is obtained by a simple subsection function. The use of these relations in conjunction with the HG equation generates a phase function similar to that given by the Mie theory equation.