Diffuse reflectance spectroscopy is a popular technique for characterization of optically scattering materials and structures, including biological tissues and organs. In order to compensate for spectral properties of the incident light and/or detection setup, such measurements regularly involve a suitable reference sample, most often made from material with high reflectance throughout the included spectral region, aka. white standards (WS). It is therefore quite surprising that the absorption and reduced scattering coefficient for Spectralon, a very popular WS material for visible and NIR region (by Labsphere, North Sutton, NH), can not be found in literature. In the only report that we could find, they were estimated only for wavelengths above 600 nm. Moreover, the analysis was based on measurements performed on rather small samples and analytical predictions derived within the diffuse approximation of light transport, which raised some concerns about its accuracy. We have therefore performed dedicated Monte Carlo simulations of the relevant optical measurements on Spectralon samples reported in literature, i.e., the total reflectance as a function of the sample thickness and angular dependence of the diffuse reflectance at different wavelengths in visible and NIR. By varying the input properties until the model predictions matched the experimental data as well as possible, we could estimate the optical properties of Spectralon between 400 and 1100 nm. For the wavelength of 555 nm, e.g., our results indicate an absorption coefficient of 0.7 . 10–4 mm–1 and reduced scattering coefficient of 32 mm–1.
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