Optical coherence tomography (OCT) is an imaging modality that can provide non-destructive and high resolution imagery of samples in a non-contact method. The technology is based around backscatter of light from different regions within samples and using scanning methods, 2D and 3D imagery of samples can be generated. 

 

Due to the wavelengths of light used, subsurface structure and surface profiles can be obtained from a wide range of materials, both in air and even immersed in fluids. OCT is similar to ultrasound imaging, with light being used instead of sound.xt to edit it.