Abstract: This invention enables a laser beam, expanding from a pinhole aperture spatial filter, to be brought back on the optical axis of an optical system such as an optical correlator system and maintained there. The principle of operation is that photodetectors spaced in the outer region of the expanding beam detect a change in orientation of the incident laser beam, and the change is measured and an error signal is used to drive electrically controlled micrometers so as to restore and maintain alignment.

Abstract: Method of fabricating a coherently exposed multiple holographic lens including a first step of fabricating an incoherently exposed master multiple holographic lens with an array of overlapping holographic lens elements, each of said lens elements having an interference pattern substantially covering the entire area of the lens. The master multiple holographic lens is illuminated with a first beam of light from a coherent source to provide a plurality of light waves equal in number to the number of lens elements in the master lens. The plurality of light waves overlap in a region downstream of the master lens. A holographic recording medium is positioned in the region of overlap such that an area thereon is illuminated simultaneously by each of the plurality of light waves. A second beam of light from a coherent source is directed toward the area of the holographic recording medium illuminated by the plurality of light waves.

Abstract: An optical correlator system, comprising a laser to generate a signal beam, an image means located in the path of the signal beam to spatially modulate the signal beam, and first and second matched filters. A multiple beam generating holographic lens is located in the path of the modulated signal beam to partially transmit the signal beam and to deflect a first matrix of replicas of the signal beam onto the first matched filter. A mirror is located in the path of the partially transmitted signal beam to reflect that transmitted beam back to the holographic lens, which deflects a second matrix of replicas of the signal beam onto the second matched filter. With an alternate embodiment, a series of holographic lenses and beam splitters are alternatively arranged along the path of the signal beam. Each holographic lens generates two matrices of beams, with each matrix of beams being focused on an associated matched filter.