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Optical Engineering

Reconstruction of multilayered dielectric models using oblique transverse electric or transverse magnetic incidence
Author(s): Essam A. Hashish; Hazem Raafat
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Paper Abstract

Subsurface probing of inhomogeneous dielectric media has received considerable attention from the research community. Extensive work in this area has been presented either in the time or frequency domain. However, most of the algorithms presented are mainly devoted to continuous dielectric profile inversion. The fast Fourier transform (FFT) inversion method is newly introduced for discrete multilayer inversion. This method has the advantages of simplicity, a short computation time, and robustness with respect to noise. The FFT inversion method is applied to a discrete homogeneous multilayer dielectric model using oblique incidence and a limited bandwidth, provided that all dielectric media are lossless and nondispersive. For a given model, a uniform plane wave is obliquely incident on the top of its surface, with its polarization being either a transverse electric or a transverse magnetic wave. In each case, the corresponding reflection coefficient is sampled over a finite frequency range. The time-domain spectrum of the reflection coefficient is obtained by applying the FFT algorithm to its samples. An algorithm is developed for the deduction of the height and permittivity of each layer. The algorithm is tested by using the simulated data of a three-layer half-space dielectric model. The resulting relative errors in the inversion process are almost less than 10-4 for all of the model parameters. When a random noise signal is superimposed on the sampled input data, the relative errors are comparable to the noise-to-level ratio.

Paper Details

Date Published: 1 April 1995
PDF: 6 pages
Opt. Eng. 34(4) doi: 10.1117/12.196460
Published in: Optical Engineering Volume 34, Issue 4
Show Author Affiliations
Essam A. Hashish, Cairo Univ. (Egypt)
Hazem Raafat, Univ. of Regina (Canada)

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