Synthetic-aperture chirp confocal imaging.

An imaging system that combines synthetic-aperture imaging, holography, and an optical chirp with confocal imaging is described and analyzed. Comparisons are made with synthetic-aperture radar systems. Adaptation of several synthetic-aperture radar techniques to the optical counterparts is suggested.

Simultaneous position and velocity measurement by interferometric imaging.

The simultaneous measurement of azimuthal position and azimuthal velocity by interferometric imaging in a grating interferometer is described. The system works with ordinary incoherent, white light.

Space bandwidth requirements for three-dimensional imagery.

Four different methods for storing a three-dimensional image are examined. The efficiency of each method, expressed in terms of the space-bandwidth product of the stored data, is calculated.

Small-aperture, high-resolution, two-channel imaging system.

A method that utilizes incoherent light interferometry is used to form images through vanishingly small apertures. The method utilizes the increased channel capacity produced by reduction of spatial coherence, but in a way thatimproves the resolution instead of the signal-to-noise ratio.

Propagation of spatial pulses in interferometrically produced guiding structures.

Image transfer properties of interferometrically produced dielectric light guides are investigated. A general technique of analysis is developed. Computer calculations based on this approach are used to study the behavior of pulses traversing the guiding structures for various values of refractive index. Experimental results are obtained using photosensitized polymethyl methacrylate as the recording material. Computer results are compared with existing theory and found to be in close agreement.

Recording of phase-amplitude images.

An interferometer comprising three diffraction gratings and an imaging system is used with spatially and spectrally noncoherent light to produce high fidelity low noise recording of phase- and -amplitude objects.

Achromatic interferometers for white light optical processing and holography.

Achromatic interferometers are developed that perform optical processing operations and record both the phase and amplitude of the output by means of a coherent reference beam. The interferometers simultaneously carry out the data processing tasks and form fringes with white light extended sources.

Noise performance of an achromatic coherent optical system.

The noise-suppression characteristics of an achromatic optical processing system when operated with a broad-spectrum light source are analyzed. It is shown that such systems produce considerable noise improvement. Both signal-dependent and signal-independent noise are considered. In each case, we find that the achromatic coherent system behaves much like an incoherent imaging system.

Broad-source image plane holography as a confocal imaging process.

The process of image plane holography with incoherent illumination has many significant properties. The process can produce extremely high-quality, low-noise images, section slicing, image formation through inhomogeneities, and high-resolution image formation through small apertures. The process of confocal imaging has similar properties. We describe the similarities and differences between the two processes.

Synthetic antenna data processing by wavefront reconstruction.

A sidelooking radar system employing a coherent optical processor is analyzed on a holographic basis. The optical system is studied in detail.

Imagery with pseudo-randomly diffused coherent illumination.

Image formation with coherent light may be improved by passing the coherent beam through a pseudorandom coded diffuser, which resembles ground glass except that it is designed in accordance with certain constraints.

Space-invariant holography with quasi-coherent light.

Optical configurations for performing holography with light of limited coherence are analyzed. Such configurations, which may employ mirrors and gratings in preference to lenses and prisms, are space invariant in that the optical pathlength of a ray between object and hologram recording planes depends only on its initial direction, not on its location in the object plane. Holograms of arbitrary size made from object transparencies of arbitrary size and light of limited coherence.

Holographic aberration compensation with partially coherent light.

The aberration-compensation method of passing the conjugate beam from a hologram through the same optical system used in making the hologram is combined with broad source interferometer techniques to give, along with the aberration compensation, considerable noise reduction. As with conventional photography, the image is two dimensional.

Grating interferometers for producing large holographic gratings.

Methods for producing large holographic diffraction gratings are described. In particular, the advantages of using a grating interferometer illuminated with a noncollimated beam from either an extended monochromatic source or an extended polychromatic source are described along with some of the problems that arise and methods to solve them. Experimental results illustrating the grating interferometer's ability to produce straight uniform fringes when illuminated with such noncollimated wavefronts are given.

Interferometric method for imaging through inhomogeneities.

A method of image formation through inhomogeneities is proposed and demonstrated. The imaging system, including inhomogeneity, is in one branch of an interferometer that produces broad-source fringes. The imaging system aperture is stopped to a small point. The effective aperture is in the other branch, which is otherwise empty.

Source image distortion description of broad source fringe formation.

A theory of broad source fringe formation in which the broad source fringe formation process is associated with distortion of the source image, is applied to an interferometer formed from diffraction gratings in tandem. It is shown that the source distortion is exactly that required to produce equally spaced fringes for all source elements. The possibility for applying this theory to the design of more complex interferometric systems that operate in extended source illumination is considered.

One-way phase conjugation with partially coherent light and superresolution.

Limitations on the one-way phase-conjugation technique are described. These limitations are reduced or eliminated by reducing the spatial coherence of the light and by reducing the aperture of the imaging system. By introducing a suitable level of superresolution of the kind previously described as superresolution by incoherent-tocoherent conversion, the aperture and coherence reductions reduce the effect of the optical path inhomogeneities. However, the aperture reduction does not degrade the diffraction-limited resolution limit.

Superresolution by spatial-temporal encoding methods.

The Lukosz technique of superresolution by spatial and temporal frequency interaction is extended. The effects of various misalignments and other errors are considered. An implementation of the technique is presented. Experimental results are given.

Three-dimensional confocal imaging of objects embedded within thick diffusing media.

Confocal scanning methods are modified to allow 3-D imaging of objects embedded within thick diffusing media. A method called exfoliative deconvolution is used to sharpen a volume image in which the blur is depth variant. Experimental results are presented.

Space-invariant achromatic grating interferometers: theory.

A general analysis of an n-grating interferometer under various conditions of illumination is presented, where n = 1,...,4. Conditions for fringe localization and effects of misalignment are given. The lesser known phenomenon of the imaging of a grating by a second grating is described from which the fringe forming capacity of multiple-grating interferometers stems; this can occur regardless of the coherence of the source.