Abstract: The disclosure describes a wide field reflective optical system comprising an afocal fore telescope and an imaging system. The afocal telescope comprises first and second confocal paraboloidal reflectors, an aperture stop located in front of the first reflector at a distance equal to its focal length, and a field stop located at the common focal point of the reflectors. The imaging system is an improvement of the Schmidt principle and comprises an aspheric corrector reflector that reflects radiation from the second paraboloidal reflector onto a plane reflector. The plane reflector is located in front of a spherical reflector that focuses radiation at its focal plane through an aperture in the plane reflector.

Abstract: A technique for irradiating a substantially large surface area so as to obtain substantially uniform radiation density over the entire surface area to be irradiated through the use of prismatic elements including elliptical shaped reflector means and a line radiation source, wherein the line radiation source and the image plane of the surface area to be irradiated are positioned at predetermined locations displaced from the normal primary and secondary focal points to cause the entire surface area to be irradiated in a substantially uniform manner.

Abstract: In testing a large aspheric mirror such as a paraboloid, one uses as interferometric reference a small spherical mirror together with a test glass. The combination of mirror and test glass produces a parabolic wavefront for comparison. Recently holograms have been used as synthetic test glasses. The average fringe distance of the grating-like holograms has to be fine enough if separation of the diffraction orders is required. We propose to use holograms with circular fringes. Now the different diffraction orders come to focus at different locations on the optical axis, where all but one order can be eliminated. This is easily possible, since the waves coming from a mirror with a central hole are hollow cones. Several ways for making these computer-generated circular holograms are suggested.

Abstract: A plurality of optical beams, encoded to have different spacially varying intensity profiles, are launched along a common wavepath. At the receiver, demultiplexing is effected by means of a converging lens which performs a two-dimensional Fourier transformation upon the multiplexed beams, producing an array of spots at the focal plane of the lens which uniquely identifies and separates the plurality of beams. It is an advantage of such a system that the spot locations are not affected by small displacements of the beams off the path axis.

Abstract: Summary Earthquake focal plane solutions are computed using P wave first motion, S wave polarization angles, and combinations of the two. The method used is based on a maximum-likelihood argument implemented by the generation of a score surface on a discrete grid. The combined score is of the form a(P-score)+b(S-score). For the P-solution and S-solution, the computer system also produces contoured fiducial regions about the poles of the focal planes. This permits an evaluation of the quality of the solutions and makes possible the comparison of solutions for different earthquakes. These contoured limits have a probabilistic interpretation as 95 per cent fiducial regions, a term explained by Pope. A new graphical method for P wave solutions makes possible the construction of exact boundaries of the regions. The Aleutian earthquake of 1969 May 14, is analysed, and the solution shows good agreement between the observed P wave first motions and the S polarization angles.

Abstract: Ordinary interferometry, hologram interferometry, contouring, speckle, moire, ordinary radar, Doppler radar, optical Doppler velocimeter, Doppler holography, and gated viewing are all discussed, and it is demonstrated how closely these methods are related to each other. One single diagram, the holo-diagram, can be used for the evaluation of each method and even for combinations of the methods. The diagram is constructed for the study of interference patterns when an object is placed in the vicinity of two focal points representing either one point of illumination and one point of observation or two points of illumination or two points of observation. It reveals interference surfaces in space and how ordinary interference fringes are formed where an object intersects these surfaces. With a common moire analogy the three-dimensional sensitivity distribution and the fringe patterns of each of the methods can be simulated. Finally it is pointed out that the diagram demonstrates the interference limits and diffraction limits of any method of optical information retrieval.

Abstract: Apparatus to perform correlation spectroscopy utilizes a zero dispersion monochromator having entrance, intermediate and exit slits. A ruled grating is located in the beam path between entrance and exit slits and is operable to disperse a beam of radiation incident thereon both prior and subsequent to radiation passage through the intermediate slit. A first axis is parallel to the grating rulings, the entrance and exit slits symmetrically disposed at opposite sides of a plane bisecting and normal to a line extending between the entrance and exit slits, the plane also passing through the intermediate slit. That axis is located to have intersection with and to extend at an angle Ψ relative to a normal to the plane that passes through said intersection thereby to substantially eliminate spectral overlap. Further, an array of sets of slits is provided adjacent the intermediate slit position of the monochromator, the sets of slits in the array being successively movable into the focal plane at the intermediate slit position.

Abstract: A method and apparatus for recording and projecting single color or multiple color encoded image-plane carrier holograms are described. An object is illuminated with a coherent collimated laser beam. The parallel spatially modulated rays are focused on a monochrome recording medium located in a recording plane with the rays maintained essentially parallel. A collimated reference beam, which is coherent with the object beam, is directed at the recording medium to form an image-plane hologram having a single discrete spatial carrier frequency in case of a single color laser or additional spatial carrier frequencies for as many colors as are in the laser. The processed image-plane hologram is projected by directing a generally collimated beam of incoherent white light upon the hologram to form separated wavefront reconstructions of parallel rays. A lens projects the parallel rays in a viewing plane after their convergence at a focal spot in a focal plane. A spatial filter located in the focal plane provides selection of desired color images and blocks undesired ghosts. A control for moving and adjustment of the spatial filter is provided to attain hue and saturation control as well as brightness of the projected image. An embodiment for recording of image-plane holograms of diffuse objects or diffusely illuminated objects as well as three-dimensional objects is described.

Abstract: A system and method for generating a shadow image of the surface of an object, the image capable of quantitative surface measurement by direct measurement of the slope of the surface at a given location, from which a surface roughness figure may be determined. Light of a defined angular distribution is directed upon the object surface. A collecting lens transmits an image of the surface to an image plane. An aperture located at the focal plane of the lens has at least a portion thereof in the light path to block out a portion of the possible angles of light passing through the collecting lens, limiting the reflected light from the surface to an angular light distribution in the beam to effect a contrast image between at least two areas in the image plane of an intensity contrast of at least two per cent.

Abstract: Summary The method of maximum likelihood is applied to find solutions for the focal plane parameters of an earthquake using P wave first motions and using S wave polarization angles. The solution is carried out numerically by generating likelihoods over a discrete grid covering the parameter space. The likelihood values are contoured to show regions of maximum likelihood. By an appropriate calibration of the contours of these regions, they can be interpreted as fiducial regions that express the quality of the focal plane determination. Alternative interpretations of these regions are discussed at some length as instances of the general problem of constructing confidence regions. This paper gives the necessary statistical background material for the paper (Determining Maximum Likelihood Focal Plane Solutions, Dillinger, Harding & Pope) but may be read separately.

Abstract: A coherent optical multichannel correlator for identifying an object to be investigated by permeating the object with a beam of coherent radiation which is received by a transformation element and projected on a filter hologram which reconstructs a reference wave received by an optical sensor when the object to be identified is correlated with a filter hologram characterized by a Fourier transformation element comprising a plurality of lenses arranged in a raster with each lens having a focal point separated from a focal point of adjacent lenses, and by the filter hologram comprising a plurality of filter holograms with each of the plurality of filter holograms associated with a separate lens of the raster. The raster of lenses may be a raster of Fresnel zone lenses. The optical sensing element may be a single element which receives the reconstructed waves from each of the filter holograms or it may be subdivided into a plurality of sensing elements with each of the elements associated to receive the reconstructed reference wave of a single hologram filter. The lenses of the raster may be arranged with the focal point of each of the lenses lying in a single plane extending vertically to the optical axis of the beam or can be arranged with the focal points lying in a plurality of different parallel planes which extend vertical to the optical axis and preferably the filter holograms are located at the focal point for its respective lens.

Abstract: A method and apparatus for positioning with respect to each other a pair of bodies such as a mask having a predetermined pattern thereon and a wafer onto which the pattern is to be printed. These bodies are respectively situated in parallel focal planes and a reference point on the body in one focal plane has an image thereof projected onto the body in the second focal plane, this latter body having a positioning point which is to coincide with this image when the bodies are properly positioned with respect to each other. A second image of the reference point is projected to an observation point, and an image of the image of the reference point on the body at the second focal plane is also projected to the observation point, so that the operator may observe at the observation point when the positioning point is located in coincidence with the image of the reference point on the body at the second focal plane.

Abstract: A ranging device for determining instrument-to-subject distance for focusing of an objective lens of the instrument on the subject. Located in the optical path of the objective lens, the ranging device includes a drive for cyclically displacing an optical means about the nodal point of that optical means to cause an image of the subject to remain stationary on an image plane when the objective is focused thereon and to cause the image to rotate in the image plane when the objective is not focused on the subject.

Abstract: Information regarding a pattern being identified is obtained by means of a photoelectric connector comprising a photoelectric surface on which a photoinput image of the pattern is to be projected, focusing means for focusing photoelectrons emitted by the photoelectric surface in response to the photoinput image to form a photoelectron image on a focal plane, means to enlarge or reduce the photo-electron image, deflecting means for moving the position of the photoelectron image in the focal plane, an array of a plurality of electron beam detecting elements which are arranged in a plane near the focal plane, each electron beam detecting element generating a current proportional to the quantity of the electron beam impinging thereupon, and a plurality of parallel output conductors respectively connected to the electron beam detecting elements. The outputs on the output conductors are processed to identify the pattern.

Abstract: An optical receiver comprising a lens system for forming an image of a distant light source at its focal plane. The light on either side of the focal plane is intercepted by a reticle of alternate opaque and transparent strips of equal widths which move at constant speed and always in the same direction across the light while the reticle continuously oscillates back and forth along the optical axis between extreme positions one of which is in the focal plane of the lens. A photodetector converts the light transmitted by the reticle into a proportionate electrical signal. An inhibit gate located between the output of the photodetector and the receiver output circuit is made to respond to the presence of an amplitude modulation of the AC component of the photodetector output at either the oscillating frequency of the reticle or twice this frequency to prevent an output from the receiver when either of these modulations is present.

Abstract: A two point focus variable magnification lens system which can be focussed at two points, the minimum and maximum focal lengths with different magnifications by the movement of the only second lens groups, and which when focussed at the minimum focal length of the maximum focal length can be made to focus for an object at either of special two distances without performing the focussing operation as far as the following conditions are satisfied, WHEREIN F1 IS THE FOCAL LENGTH OF THE FIRST LENS GROUP, F2 IS THE FOCAL LENGTH OF THE SECOND LENS GROUP, S1 IS THE DISTANCE OF A SPECIAL FARTHER SIDE OF OBJECTS FROM THE FRONT END OF THE LENS SYSTEM IN THE CASE OF THE MINIMUM FOCAL LENGTH, S2 IS THE DISTANCE OF A SPECIAL NEARER SIDE OF OBJECTS FROM THE FRONT END OF THE LENS SYSTEM, xi O IS THE DISPLACEMENT LENGTH OF THE SECOND LENS GROUP, K = 1 2ROOT z (z: the variation ratio of magnification), ln is the interval between the principal points of the first and second lens groups in the case of the maximum focal length, x is the distance from the front principal point of the first lens group to the point of image formed of an object at a special farther side by the first lens group in the case of the minimum focal length, and y is f2(1 - K)2/k.

Abstract: Holographic imaging as a projective transformation is discussed and coefficients of the transformation equations are determined for five types of mutual conjugation. Locations of cardinal points also are determined. On the basis of the relations for the coordinates of cardinal points the graphical determination of the optical axes is indicated. At the end, geometric constructions of image points for all types of conjugation are developed and illustrated on the example of the imaging of a square localized in the meridional plane.

Abstract: A general expression for the exposure transfer function of a photographic system employing a focal-plane shutter is derived which includes the effects of uniform, linear image-motion. The results show that the modulation transfer function (MTF) of such a system is upper bounded by the product of the diffraction-limited optical MTF and a term strongly coupling the shutter and motion effects. The coupling of these effects results in a general solution dependent upon the size and shape of the pupil and the aberrations of the optical system.

Abstract: A scanning device with rotatable plane mirror surfaces movable about the radius of curvature of a cylindrical mirror and positioned to pass through the focal plane of the cylindrical mirror. A light beam relayed from the movable plane mirror is reflected from the cylindrical mirror along a path parallel to the optical axis of the device for each successive position of the plane mirror.

Abstract: 1276553 Lamps GTE SYLVANIA Inc 12 Aug 1969 [14 Aug 1968] 40336/69 Heading F4R A lamp, particularly a vehicle headlamp, of the kind in which an optical element, such as a lens or ellipsoidal reflector, forms an image of a light source at the rear focal plane of a projection lens has a gate disposed at the rear focal plane to define a sharp cut-off along part of the edge of the projected beam and a filter spaced from the gate at an out-of-focus position, the filter having zones of different densities to provide a gradual cut-off along the remaining part of the edge of the beam.

Abstract: 1,270,030. Remote observation apparatus. COMMISSARIAT A L'ENERGIE ATOMIQUE. July 2, 1969 [July 10, 1968], No.33373/69. Heading G2J. An apparatus for the remote observation of objects has an objective 2 of variable focal length and an adjustable lens group 4 transmitting a parallel light beam to a fixed lens group 6, a first mirror system 16, 18 and a second mirror system 8 for deflecting a beam to an eye piece unit 10 also being provided. An image of the object is transmitted through glass window 104, mirror 106 and objective 2 on to the front focal plane of lens group 4 which passes the image through mirror 16, 18 lens group 6, either to binocular eye-piece 10 or to a photographic recording system 12 via movable mirror system 8. The remote adjustment of the lens elements of 2 and 4 is achieved by a system of toothed wheels and connecting rods attached to a set of manual control knobs adjacent the eye-piece unit 10. Alternatively an electric control system may be used. The apparatus comprises tubes 14, 3, 1 the latter being slidable on rollers 101 into a projecting tube 102 set in the wall 100 of a leak proof chamber e. g. a furnace or pressure or vacuum chamber, the window 104 and the flange 108 sealing the apparatus. The mirror 8, Fig. 12 (not shown), is pivotable on stand (88) via a spring and pivot arrangement by knob (97), two arms (98) and a stop (96) limiting the movement. The mirrors 16, 18 may be replaced by a single mirror.

Abstract: An optical data processing system using paraboloidal reflecting surfaces is disclosed. In the preferred embodiment the paraboloidal reflecting surfaces are segments of a paraboloidal mirror. A source of coherent light is in the focal plane of the first paraboloidal mirror segment which collimates the beam and reflects it toward a second paraboloidal mirror surface. The information to be analyzed, on a transparency for example, is placed in the collimated beam. The beam is reflected from the second paraboloidal mirror segment and focused on a Fourier transform plane. A photon detector could be placed in the Fourier transform plane or suitable spatial filters can be placed thereat, with the filtered beam then being reflected from a third paraboloidal mirror segment to be focused on a reconstruction plane.

Abstract: A fiber optics image-transferring element is nonisoplanatic over a surface region containing only a few fundamental resolution elements, and no meaningful or consistent evaluation of a fiber optics image can be made by examining such a nonisoplanatic region. A holographic scheme offers a solution to the problem of fiber optics image evaluation based upon examination of a nonisoplanatic region. Interfering plane waves are used to create a sinusoidal irradiance distribution that is continuous over the entire fiber optics input surface. Subsequent holographic evaluation of the photographically recorded input and output yields values of a statistical MTF by comparing the amplitude of a sinusoidal input to the average amplitude of the sinusoidal output component. The design and operation of such a holographic system is presented, and an experiment that demonstrates the advantages of the holographic measurement is discussed.

Abstract: We have evaluated the principal optical characteristics of paraboloid-hyperboloid x-ray telescopes by a ray-tracing procedure; we find that our results for resolution, focal plane curvature, and finite source distance effects may be approximated in terms of the design parameters by simple empirical formulas.