Abstract: The holographic recording system comprises a pair of aligned first and second Fourier transforming lenses, a holographic beam splitter having a series of random phase illumination holograms at a front focal plane of the first lens and arranged to move in a given direction to successively receive a light beam for deffracting it into a zero-order diffracted beam and a first-order diffracted array of sampled, phase shifted beams, and a mask having a first and second apertures disposed at the Fourier transform plane of the first lens. A page composer having electrooptical transducers is positioned in the second aperture to receive the first-order diffracted array of beams to spatially optically modulate the incident beams in accordance with one of successive groups of binary signals.

Abstract: A non-destructive readout scheme suitable for use with a holographic storage system having data stored in three spatial dimensions and one frequency dimension is described. The readout scheme and the holographic storage system use a preferred storage material which undergoes a reversible photochromic reaction involving two inhomogeneously broadened absorption bands. Information is written into the storage system by exposing the material to a holographic interference pattern of light at a frequency within either one of the two absorption bands. The non-destructive readout scheme involves reconstructing the original information by sensing the change in the index of refraction at a frequency just outside of and near either one of the two absorption bands. The readout scheme also includes sensing refractive index changes near one or more narrow absorption lines within either absorption band.

Abstract: A system for recording and reproducing information using Fourier transform holography wherein original information to be recorded as holograms is divided into a number of groups each including N(N .gtoreq.2) information units, each unit including a given amount of information. This information is recorded by a holographic technique on a track or tracks of a record medium as a series of holograms from a plurality of unit-information input positions, or from a single unit-information input position when a reference light having a plurality of incident angles is used. In reproducing, the images either analog or digital are reproduced such that images reproduced from adjacent holograms in the series of holograms on the track appear at, at least two different positions on an image plane of a reproducing system such as pickup tubes or a photodiode array.

Abstract: A wideband holographic information storage system records Fourier holograms on film in rapid succession, each hologram storing 128 bits of data. The hologram fringe pattern is held stationary by varying the reference beam frequency to track the variations of frequency of the signal beam that are caused by acoustic-optic modulation of the signal beam. Holograms are successively recorded in adjacent positions by scanning a light beam across a photosensitive film with a rotating polygonal mirror, the recording light beam being wide enough to cover two facets of the mirror so as to achieve nearly 100% scanning duty cycle. During readout, a readout light beam is steered to compensate for prismatic deflection effects caused by variations in thickness of the film.