Abstract: An apparatus and a method employ on a subject at least one holographic optical element that develops two beams of focused light whose focal configurations appear in predetermined locations which correspond to the position of the subject in the system. In a first preferred embodiment, two holographic optical elements are recorded on a subject that is to be aligned and supported by a holder assembly. During exposure of the holographic optical elements, the light rays passing through the plate converge of two focal points that have position coordinates which define their locations in the coordinate space of the optical system. Each focused point of light strikes a position sensitive detector which develops output signals that represent the position coordinates of the focused point of light in the system.

Abstract: A method and apparatus for performing optical processing on optical information corresponding to a subject (66) combines known optical processing techniques with holography. A reverse ray-trace holographic system is provided so that the image reconstruction beam (90) passes through the optical system in a direction exactly opposite to that travelled by the subject beam (50) during recording of the hologram (88). Aberrations introduced by the system optics are then completely compensated for, allowing use of lower quality optical components. A single large-aperture lens (68) is used to define a Fourier transform of the optical subject information as the hologram (88) is recorded or the image reconstructed, and the subject information is manipulated within the Fourier transform plane (91).

Abstract: High performance optical spatial filters are produced photographically with an apparatus that directs a coherent beam of light through or off a subject and into a lens. The lens focuses the diffracted and/or reflected light to define a Fourier transform of the subject information. A filter is produced by exposing a photographic plate at the Fourier transform plane, processing the plate, and repositioning it. A hologram is recorded through the processed plate with the apparatus, which directs a reference beam to a holographic recording plane. A second photographic plate is placed at the transform plane and exposed with light directed through the hologram from a direction conjugate to the reference beam. The second plate is then processed. Successive generations of filters may also be produced. A method of using the filters for isolating nonperiodic defects in IC photomasks and wafers is also disclosed.

Abstract: An apparatus for the production of a holographic image of a subject disposed at a subject plane includes a source of coherent light divided by a beamsplitter into a reference beam and a subject beam. The subject beam is directed towards the subject through a beamsplitter and a quarter-wave plate. The front surface of an opaque subject or a mirror behind a transparent subject reflects the subject beam back through the quarter-wave plate to the beamsplitter where it is deflected towards a photo-sensitive recording medium through an imaging lens. The reference beam is simultaneously directed toward the recording medium at a predetermined angle of incidence. After exposure and development of the medium, it is illuminated from the conjugate direction by the redirected reference beam. Image rays exactly retrace their original paths back through the optical system and provide a three-dimensional real-image reconstruction at the subject plane.

Abstract: In a method and apparatus for recording a holographic image on a photosensitive medium or film which is capable of being viewed from a wide vertical viewing angle when illuminated by incoherent light, a source of coherent light (10) is divided by splitter (14) into a reference beam (16) and an image or object beam (18). The image beam is directed toward the object, either a transparency (20) or a three-dimensional object (20a), and the image thereof is focused in the vertical plane by means of an anamorphic lens (30) onto a vertical dispersion element (35) and the image thereon is gathered and focused in the vertical plane by means of anamorphic lenses (36 and 38) onto the film (40). In the horizontal plane, the image is focused by an anamorphic lens (42) onto a horizontal exit pupil forming means which may include horizontal dispersion element (45) and the light therefrom is directed onto the film (40).