Extracting broadband optical properties from uniform optical phantoms using an integrating sphere and inverse adding-doubling

In tissue optics, it is important to measure the wavelength-dependent scattering, absorption and anisotropy coefficients of tissues to describe interactions of light with such turbid media. Here, we use the inverse adding-doubling (IAD) technique coupled to measurements acquired using an integrating sphere (IS). The IS system provides a method to acquire highly accurate measurements for the total reflectance and transmittance for thin turbid samples. The IAD is an iterative technique that uses a numerical solver to radiative transport capable of fitting a set of measured reflectance and transmittance values and thereby yield optical absorption and reduced scattering coefficients of thin samples. We test the validity and performance of the IS/IAD system by obtaining measurements on a set of liquid phantoms prepared with controlled absorption and scattering properties. We explore sources of errors and discuss how the the accuracy these techniques may be improved. We demonstrate that the IAD/IS technique allows the accurate recovery of chromophore spectral properties.