Optical coherence tomography (OCT) is an interferometric, non-invasive optical tomographic with ~30µm axial resolution. OCT has achieve sub-micrometre resolution in 2001 due to introduction of wide bandwidth light sources (sources emitting wavelengths over a ~100 nm range). By now OCT has found its place as a widely accepted imaging technique, especially in ophthalmology, other biomedical applications and art conservation.