Abstract

Diffraction tomographic imaging algorithms use measurements of scattering from semitransparent objects to generate volume (2-D or 3-D) reconstructions of microscopic objects. An efficient direct reconstruction formula is imbedded in the filtered backpropagation algorithm. This algorithm, when applied on transmission scattering data, uses scattered fields within the homogeneous plan wave spectrum domain to generate quantitative reconstructions with spatial resolution of $\lambda /\sqrt{3}$. Availability of near-field scanning probe technology will allow measurements with subwavelength resolution. These data, having evanescent plane wave spectra, contain information on the object with a resolution better than $\lambda /\sqrt{2}$ but cannot be incorporated into the filtered backpropagation algorithm in its presently known form. We present a generalization to the filtered backpropagation algorithm that uses evanescent plane wave spectra from scattering data to improve the resolution of reconstructions beyond the $\lambda /\sqrt{2}$ limit.

© 1991 Optical Society of America