Abstract: A hologram is written from x, y, z data by presenting an information beam at a holographic medium with x and y coordinates represented by x and y position on the medium and z coordinates represented by distance between the holographic medium and a point position of the beam close to the medium, while simultaneously presenting a reference beam in interference with the information beam and of a size comparable with the size of the information beam at the holographic medium. The area of the information beam and the reference beam at any position on the holographic medium is a small fraction of the total area of the hologram.

Abstract: Coherent light such as a laser beam is spatially modulated by causing it to interact at a photosensitive material such as a crystal with a focussed image of non-coherent light. An electric potential is applied to the crystal either transversely to the direction of the light or in line with the direction of the light according to either the Kerr effect or the Pockels effect. Typical crystals include Bismuth-silicon-oxide and strontium-barium-niobate.

Abstract: Image enhancement is achieved to increase the ability to distinguish details otherwise difficult to discern in bright and dark areas of a photorecord by reflecting light off surface perturbations on the record and displaying the reflected light by means of schlieren optics.