Information content of the Born field scattered by an embedded slab: multifrequency, multiview, and multifrequency-multiview cases

The information content of the scattered field in the framework of the line ar Born and distorted Born approximations for a one-dimensional lossless di electric permittivity profile embedded in a lossless homogeneous halfspace is analyzed. The number of degrees of freedom of the scattered held and the class of the retrievable profiles from a multifrequency, a multiview, and a multifrequency-multiview configuration are evaluated by analytical consid erations and validated by numerical singular-value decomposition. The analy sis stresses the effects of the background permittivity value on the degree s of freedom and on the class of retrievable profiles within the distorted Born approximation. In particular, the results show that, for high values o f the halfspace permittivity, the information content in the multiview appr oach at a fixed frequency becomes too poor to yield effective reconstructio ns, whereas a suitable multifrequency or multifrequency-multiview approach can provide better results. (C) 1999 Optical Society of America [S0740-3232 (99)00110-6].