Fast wavefront manipulation for OCT signal enhancement

Due to its capability to quickly capture volumetric images with microscopic resolution, optical coherence tomography (OCT) has become a valuable tool for medical diagnosis. Strong scattering in samples such as human skin causes the detected signal to decrease rapidly with increasing penetration depth, however, and limits OCT imaging to thin samples. Scattering of light is a deterministic process and, thus, the complex-valued amplitude of the field inside, transmitted or backscattered from a sample is affected by manipulation of the incident field, e.g. by using a spatial light modulator for shaping of the optical wavefront. Application of a suitable incident wavefront can cause the backscattered field to interfere constructively and, thus, enhance the OCT signal detected from the scattering medium. In our contribution we demonstrate non-invasive acquisition of the depth-resolved reflection matrix with a scattering sample. The technique allows for fast depth-selective OCT signal enhancement. The impact on OCT imaging in strongly scattering media is discussed.