ABSTRACT

Tissue absorption varies for different wavelengths. Examples of light-absorbing tissue constituents or chromophores are melanin, hemoglobin, oxyhemoglobin, bilirubin, cytochrome and water. Figure 1.1 gives the absorption coefficient of the most important of these chromophores at 250 nm to 2.5 µm. The wavelength range of interest for OCT is approximately from 700 nm to 2 µm, because the emission spectra of light sources used in most commercial and experimental OCT systems are in this range. The µa’s of water, hemoglobin, oxyhemoglobin and melanin were collected from the literature by Scott Prahl and Steve Jacques and can be found together with other data on https:// omlc.org.edu/spectra. For water, the data of Hale and Querry were used2.