Multifocus tomographic algorithm for measuring optically thick specimens

A novel tomographic algorithm for reconstructing the two-dimensional refractive index fluctuations of an optically thick phase object from one-dimensional projections acquired at a multiplicity of focal positions and a multiplicity of angular orientations is described. The new method is validated by measurements of multicore and microstructured optical fibers using interference microscopy. The method will benefit other transverse fiber measurement technologies and is broadly applicable to any tomographic reconstruction problem in which the transverse dimension of the specimen is substantially larger than the depth-of-field of the imaging system. (C) 2013 Optical Society of America