# Optical properties file

Optical properties files are key-files contain $\mu_a$, $\mu'_s$, and refractive index information for each region in the modeled domain. They work slightly differently for makeAnirfast() and makeAanalytic(). In both cases, you need to define the wavelengths with:

• LAMBDA: a vector with each wavelength (in nm).

For makeAnirfast() you need a line for each property and region names in the region file.

• MUA_NAME: absorption coefficient (in mm^-1) for the region NAME. This should be a vector with one value per wavelength.
• MUSP_NAME: the same for reduced scattering coefficient (mm^-1).
• N_NAME: index of refraction for each region and wavelength.

For makeAanalytic() there are no regions, so you simply enter each line without the NAME:

• MUA
• MUSP
• N