Abstract: A holographic data storage system for the storage and retrieval of data which includes in combination input means adapted to produce a number of coherent beams; wavefront matching means comprising at least one cylindrical lens for facilitating the discrimination of date; a storage medium adapted to store a number of data tracks, and capable of movement in a plane perpendicular to the plane of incidence; stepping means which is adapted to direct the number of beams produced by the input means on to the storage medium in a manner whereby a number of data tracks are recorded or retrieved, and read out means capable of controllable selective retrieval of date.

Abstract: A holographic recording method and device is disclosed in which the recording medium is a photochromic material in which a holographic record is recorded by bleaching the photochromic material using a laser beam. The photochromic materials are a class of fulgides and fulgimides.

Abstract: A scanning system which includes a rotatable multifaceted polygon, the faceted surfaces of which are optically reflective; a recording means spaced-apart from the said polygon and adapted to move in a direction parallel to the rotational axis of the polygon; light generating means for generating at least one pair of light beams, the light beams of each pair being directed at different angles onto the faceted surface in a manner whereby the regions of the faceted surface illuminated by the beams are in contact with each other in a non-overlapping relationship; modulating means for modulating the said at least one pair of light beams; and focussing means interposed between the said polygon and the said recording means for focussing each pair of light beams reflected from the said polygon onto the said recording means.

Abstract: An apparatus for treating continuous unexpanded structural honeycomb material formed of permanently creasable material comprises rollers for drawing the material in the expansion direction whilst compressing it perpendicularly thereto so that it adopts a second unexpanded state. A guide receives the advancing material and permits slight re-expansion and a double acting severing device, e.g. a circular blade driven by a double-acting ram in forward and return strokes, severs the slightly re-expanded material to form cut lengths. The severing device may be located at the position of a guide of compact form, or at the outlet end of a guide in the form of a channel having at least one resilient wall. A receiving surface, formed in part by a conveyor belt may be provided to receive the cut lengths and allow them to expand. Guides for the expanded material may be arranged to discharge the expanded material from the receiving surface.