Abstract

A novel tomographic imaging procedure has recently been proposed [1] for reconstructing the complex index of refraction profile of a semi-transparent, three-dimensional inhomogeneous object from measurements of the intensity of the fields generated by the object in a sequence of scattering experiments. This procedure is briefly described and compared with earlier work of a similar nature by Wolf [2] and Carter [3], and is illustrated by a number of computer simulated examples. We also report on experimental results obtained using the procedure to reconstruct the index of refraction profile of an optical fiber suspended in an index matching bath. The experiment consisted of illuminating the suspended fiber with a collimated He-Ne laser beam, and measuring the resulting far-field intensity pattern with a scanned photomultiplier tube. The measured intensity pattern, which is effectively a Gabor hologram of the scattered field, is then employed in the reconstruction algorithm implemented on a PC. The reconstruction of the index profile of the fiber is found to be in very good agreement with the actual index profile as estimated from manufacturer specifications and optical microscopy. The talk includes a brief discussion of the use of the imaging procedure in coherent optical microscopy of optically thick samples.

© 1990 Optical Society of America