Abstract: An imaging spectrometer to form a spectrally resolved image of an object, the spectrometer comprising three curved reflecting surfaces, an optical path between the object and the image comprising reflections from the three curved reflecting surfaces. The spectrometer further comprises dispersing elements each with a curved surface in the optical path. One dispersing element is located in the optical path between the object and a first of the curved reflecting surfaces; another dispersing element is located in the optical path between the image and a third of the curved reflecting surfaces. The majority of the spectrometer's dispersive power may be provided by optical elements in the optical paths between the object and the first of the curved reflecting surfaces and between the image and the third of the curved reflecting surfaces.

Abstract: An optical arrangement, particularly for ground-based flight simulating apparatus of the type using an optical probe moving over a terrain model to provide a visual display of terrain overflown. In such apparatus, during simulated flight, variation of tilt of the model surface relatively to the probe optical axis gives rise to a primary image also tilted relatively to the probe optical axis. The invention solves the problem of providing an in-focus image on a television camera tube the target of which is fixed orthogonal to the probe axis. The arrangement comprises first and second optical imaging systems, and optical axis deflecting means therebetween, usually lens, prism or mirror elements, producing a tilt of the in-focus image plane of the overall system, to compensate for the primary image tilt. The optical arrangement may equally be applied to a laser beam scanned terrain model.

Abstract: An optical system for selectively modulating one or more colors of light in a polychromatic light beam. Using a laser source, all colors are initially plane polarized in a preferred direction. Any selected color is modulated using an electro-optic cell with an optical waveplate both before and following. The first waveplate rotates the direction of polarization of that selected color or another color to a direction at 45.degree. to the preferred direction. The electro-optic cell resolves incident light, solely of the selected color, into two right angle components polarized at .+-.45.degree. to the polarization of said another color. The relative amplitudes of the components is determined by an electrical signal applied to the cell. The second waveplate also rotates the direction of polarization of said selected color or said another color by 45.degree.. A final optical analyzer passes one component of all modulated colors while inhibiting the other component.

Abstract: A mirror drum type of light beam, or other radiation beam, scanning device comprising a rotating mirror drum and an arcuate set of optical, or like, elements arranged coaxially with the mirror drum. An incident beam, directed upon the mirror drum strikes each mirror face in turn as the drum rotates. Each mirror face sweeps the reflected beam across each optical element in turn of the arcuate set. Each optical element is adapted to return the beam to the same mirror face whence it came. The same beam is thereby deflected a second time by the same mirror face to produce an angular rate of rotation of the final reflected beam of four times the angular rate of rotation of the mirror drum.In a modification, a second mirror drum, with convex mirror faces, sweeps the beam over a concave mirror as a pre-scanner, so that the beam follows the reflecting mirror face of the main mirror drum, in rotation.

Abstract: An optical arrangement, particularly for ground-based flight simulating apparatus using an optical probe moving over a terrain model to provide a visual display of terrain overflown.The optical arrangement provides a fully in-focus image on a television camera tube target which is inclined relatively to the plane of the terrain model.The optical arrangement may equally be applied to a laser beam scanned terrain model.The arrangement comprises first and second optical systems, usually lenses or lens combinations, and a deflecting means therebetween, usually lens, prism and mirror elements, producing a tilt of the in-focus image plane of the overall system.

Abstract: A mirror drum type of light beam, or other radiation beam, scanning device comprising a rotating mirror drum and an arcuate set of optical, or like, elements arranged coaxially with the mirror drum. An incident beam, directed upon the mirror drum strikes each mirror face in turn as the drum rotates. Each mirror face sweeps the reflected beam across each optical element in turn of the arcuate set. Each optical element is adapted to return the beam to the same mirror face whence it came. The same beam is thereby deflected a second time by the same mirror face to produce an angular rate of rotation of the final reflected beam of four times the angular rate of rotation of the mirror drum.In a modification, a second mirror drum, with convex mirror faces, sweeps the beam over a concave mirror as a pre-scanner, so that the beam follows the reflecting mirror face of the main mirror drum, in rotation.