Light propagation in turbid media: Application to biological tissues

The analysis of the propagation of light through media is fundamental for a great variety of applications, including non-guided or fiber-based guided optical communications, industrial optical cutting or welding, and biomedical optics. These applications employ sometimes heterogeneous turbid media, such as ocean water, the atmosphere or biological tissues. Turbid media present both strong absorption and scattering. As a consequence light propagation in turbid media is a complex and challenging problem. This is specially relevant in optical treatment and diagnosis of biological tissues. In this work, we describe different approaches to the calculus of light propagation in turbid media. Light-matter general interaction is first considered. Turbid media are described by means of fundamental optical properties. Special attention is paid to scattering due to its complexity. Biological tissues are classified and the most relevant morphological and optical characteristics are described. Several light propagation models are proposed, applied to the most common biological tissues, and compared. The results are essential for an adequate planning of safe optical treatments, in which no collateral damage is produced, and for obtaining high-resolution images of pathologies in order to provide an early diagnosis.