Edge-illuminated holograms.

Design and construction considerations and performance characteristics of edge-illuminated holograms are described. The display system layouts presented are compact, monolithic, and achromatic, and the light usage efficiency is improved by recycling the undiffracted hologram-illuminating beam.

Multiple Fourier transform generation for coherent optical correlators.

An interferometrically generated off-axis holographic optical element images a laser diode light source to a 3 x 5 point array through 10 cm of glass. The element also reduces the elliptical beam cross section from 3:1 to 1.5:1.

Interferometric construction of circular gratings.

Low noise diffraction gratings are constructed with the aid of a circular grating interferometer illuminated with a polychromatic or extended source.

Noise suppression in coherent imaging.

Several noise suppression techniques in coherent imaging systems are described. For holographic imaging the diffuse wave, periodic phase modulation, and multiple wave techniques are compared and the implementation of the last is considered. For lens-type imaging systems the use of multiple incoherent waves results in excellent noise suppression.

Diffraction efficiency of bleached, photographically recorded interference patterns.

An experimental study has been made of techniques that can increase the diffraction efficiency of photographically recorded three-dimensional interference patterns. The efficiency is increased by using bleaching processes that convert the silver image into a dielectric image. Diffraction efficiency vs transmittance curves, chemical formulas of some bleaches, and the bleaching procedures are given. A maximum efficiency of 60% has been achieved. Applications to holography and partitioned zone plates are demonstrated.

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.

Improvement of two-dimensional image quality in coherent optical systems.

When coherent light is used for imaging transparent objects, the images may be inferior because of Fresnel diffraction patterns from scattered light or may be degraded by granularity from diffuse illumination. This paper proposes a technique for improving image quality by using a spatially phase-modulated wavefront to illuminate the object. Analysis shows that the resulting image should be free from Fresnel diffraction patterns and should have a negligible amount of residual granularity. Experimental results verify these conclusions. Requirements of the imaging system and the wavefront are discussed. The technique is applicable to any nondiffuse, two-dimensional object and can be used in holography or with any other coherent imaging system.

Correction of lens aberrations by means of holograms.

Holograms are made of a wavefront emerging from a lens having spherical aberration. The hologram, when used in combination with the lens, serves as a corrector plate for the lens. Experimental results are given, followed by a third-order analysis.

Holographic data storage in three-dimensional media.

The holographic storage of diffraction patterns in a three-dimensional media is described from a vector viewpoint derived from the Kirchhoff diffraction integral. The sensitivity of the reconstruction to wavelength and to the orientation of the readout beam is calculated, and experimental results are given.