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A new approach using the diffraction method of linear superposition is used for the analytical description of an imperfect Fabry-Perot etalon. Derived simple relations for the transfer coefficients of a corrugated thin-film system may find a broader field of application.

A hybrid optical/digital processing scheme for measuring phase distributions is described and demonstrated. It is intended to be an alternative to interferometric methods of measuring optical path length changes in flow diagnostics and can also be used as a flow visualization technique. The processing scheme enables one to make accurate measurements of phase at arbitrary points in the image plane. The system is based on a simple coherent optical Fourier processor but incorporates three separate measurements and postdetection digital processing to eliminate extraneous parts of the signal. The addition of a holographic filter to the system enables one to measure deformation or displacement of diffusely reflecting opaque objects. The technique is demonstrated by using it to visualize the flow of an expanding compressible gas jet and to measure the optical path length through a heated plume of air.

The paper relates to hologram synthesis from 2-D transparencies. A synthetic field hologram, that is, a synthetic hologram with the diffraction efficiency unimpaired by the number of basic holograms overlapping each other on a synthetic field hologram, is presented. This hologram may be reconstructed in white light. The hologram and method of its creation can be used for making holographic land maps.

Fringe formation and localization in holographic interferometry of transparent media are discussed for configurations in which light enters the medium and is scattered back through it by an embedded diffuse object. Fringe order numbers are doubled, and the fringe localization region is translated and compressed by a factor of 2. The results are applicable to tomographic reconstruction of aerodynamic density fields around opaque test objects.

The formation of images of semitransparent spherical particles illuminated with coherent light is described from a diffraction theory viewpoint. Such images are distinctly different from those of opaque particles. The primary optical phenomena involved are illustrated by experimental results, and practical implications for holographic imaging of sprays are noted.

The performance of a magneto-optic readout system can be degraded by a phase shift between two basic polarization components of a readout beam. One source of this phase shift is undesired birefringence in the substrate of an optical disk. The effect of disk birefringence on the signal-to-noise ratio of a differential magneto-optic readout is evaluated. It is shown that this effect may be represented by two parameters J_2 and J_3 that depend only on the birefringence and the numerical aperture of a beam illuminating the disk. Previous papers on this subject either presented involved, open-form expressions for the differential magneto-optic readout or assumed that the beam illuminating the disk is collimated. Here simple closed-form formulas are derived by using parameters J_2 and J_3. The effects of system conditions that can interact with the disk birefringence, such as an imbalance between the differential data detectors, are also considered.

An algorithm for computer tomography has been developed that is applicable to reconstruction from data having incomplete projections because an opaque object blocks some of the probing radiation as it passes through the object field. The algorithm is based on iteration between the object domain and the projection (Radon transform) domain. Reconstructions are computed during each iteration by the well-known convolution method. Although it is demonstrated that this algorithm does not converge, an empirically justified criterion for terminating the iteration when the most accurate estimate has been computed is presented. The algorithm has been studied by using it to reconstruct several different object fields with several different opaque regions. It also has been used to reconstruct aerodynamic density fields from interferometric data recorded in wind tunnel tests.