Contrast increasing method for coherence tomographic imaging

摘要

The method enhances contrast in optical coherence tomography by scanning an object with partially coherent light beams and by detecting the low position of the light emitting points inside the object by means of partial coherence interferometry. The interferometric measurement beam which scans the object is a double beam obtained through beam splitting. The two interferometric partial beams from the beam splitter to the object and back to the photodetector in the interferometer provide a total path difference of a half wavelength or an odd number multiple thereof. Thus with an homogenous object structure the light bundles from the two object points destructively interfere with each other in the interferometer. In the device for carrying out the method, the two partial beams are generated by wavefront splitting using a beam splitter reflector (13) with a beam splitter surface and an mirror surface. These surfaces are at an angle to each other and lie on a path to provide the required path difference.