ADVANCES IN APPLICATION OF OPTICAL COHERENCE TOMOGRAPHY TO MATERIAL STUDIES: PRELIMINARY RESULTS WITH COMPOSITES

摘要

Optical coherence tomography (OCT) was developed for and has proven to be of value in the field of biomedical imaging. OCT is a coherent optical gating technique that allows excellent discrimination against scattered light that arrives to the detector at a time, which is different from that of the image. This allows three-dimensional imaging below the surface of turbid media, where multiply scattered incoherent light precludes conventional imaging. OCT is based on the heterodyne detection and can reach dynamic range of better than 10~(11). Even with the raster scanning, video rate imaging was demonstrated. OCT is mostly appropriate for detecting microscopic defects in the near surface regions of various materials where ultrasound and X-Rays may have difficulties. We applied OCT towards subsurface imaging in various materials.