General principles
Optical Coherence Tomography; applications to retinal and biofilm imaging

In this section, we'll take a look at optical coherence tomography (OCT), explaining what it is, what it can measure and what it's used for, without going into the technical details of implementation, which will be covered later in the article.

First, we'll explain how light propagation time can be measured to quantify the depth of the structures that make up a sample. Next, we'll look at the various theories that predict the amount of light reflected by the different structures visible in OCT as a function of the size regimes of these structures. Finally, we'll explain the imaging principles that help us understand why and in what cases OCT is an imaging technique of interest.