Abstract: A device is provided for establishing the uniformity of wall thickness for a plurality of hollow spherical shells suspended in a liquid. Specifically, the device imposes a variable angular acceleration on each shell in order to establish a uniform wall thickness for each shell. The device includes a container for receiving the liquid and the suspended shells. Further, the device includes a motor for moving the liquid to impose a variable angular acceleration on each shell. Also, the device includes an element for polymerizing each shell after each shell's wall thickness has become substantially uniform.

Abstract: An image projection system comprises a laser source that generates a series of periodic pulses having substantially uniform energy content, a spatial light modulator, and a modulator driver synchronized with the laser pulses so that transition intervals of the modulator elements occur in an interpulse period between first and second states of the modulator elements. Because the pulses are substantially equal in energy, and the transitions of the modulator elements occur in interpulse intervals, the collective energy delivered to any pixel in the system described herein during the period of one frame is a direct function of the number of pulses, which can be accurately controlled in a digital manner.

Abstract: A single frequency filter for a laser, comprising a polarizer that defines a direction of polarization and one or more birefringent elements situated within the cavity with their dielectric axes offset from the direction of polarization. The ends of the birefringent elements have a finite reflectance, and may be coated for reflectance or left uncoated. In some embodiments the filter is situated in a laser cavity with a broadband gain medium, in other embodiments, the filter is situated in an external cavity. To provide tunability, a wavelength control system is coupled to the birefringent element. An embodiment is described in which the filter comprises two birefringent elements of unequal optical length along the optical axis, which advantageously reduces the voltage required to tune the frequency. To provide tunability, the first and second birefringent elements are both coupled to a wavelength control system that simultaneously controls both elements.

Abstract: A multi-screen laser projection system comprises a laser source that generates a plurality of laser beams, an image display control system, a plurality of modulator arms each including a light modulator; and an optical switch coupled to the image display control system and modulators. A plurality of projection optical systems are respectively arranged to project the modulated light from each modulator onto its associated screen. The optical switch is arranged to receive the plurality of beams from the laser source and switch each of the beams to one of the modulator arms in order to illuminate each modulator with a sequence of colors during each frame. During the course of a frame, each of the colors becomes incident upon the modulator. The projection system disclosed herein can provide a cost-effective, efficient true digital projection display system with high resolution and high brightness.

Abstract: A single frequency filter for a laser, comprising a polarizer that defines a direction of polarization and one or more birefringent elements situated within the cavity with their dielectric axes offset from the direction of polarization. The ends of the birefringent elements have a finite reflectance, and may be coated for reflectance or left uncoated. In some embodiments the filter is situated in a laser cavity with a broadband gain medium, in other embodiments, the filter is situated in an external cavity. To provide tunability, a wavelength control system is coupled to the birefringent element. An embodiment is described in which the filter comprises two birefringent elements of unequal optical length along the optical axis, which advantageously reduces the voltage required to tune the frequency. To provide tunability, the first and second birefringent elements are both coupled to a wavelength control system that simultaneously controls both elements.

Abstract: A laser in which the laser emission is autocoupled into an optical fiber. The laser cavity is insensitive to misalignment; i.e. it will oscillate if the optical fiber is positioned within an allowed volume determined by a degenerate resonator configuration. In one embodiment, a solid state laser includes two ball lenses arranged on opposing sides of the gain medium. The degenerate resonator configuration is defined on one end by a reflectively-coated outer surface of the ball lens. The other end is approximately defined by an allowed volume on the outer surface of the second ball lens. To provide a laser cavity the reflective end of the optical fiber is situated within the allowed volume. The laser may be end-pumped using a fiber-coupled laser diode, and the ball lens is used to focus the pump beam into the gain medium. The reflective end may be provided by a Bragg grating.

Abstract: A multi-screen laser projection system comprises a laser source that generates a plurality of laser beams, an image display control system, a plurality of modulator arms each including a light modulator; and an optical switch coupled to the image display control system and modulators. A plurality of projection optical systems are respectively arranged to project the modulated light from each modulator onto its associated screen. The optical switch is arranged to receive the plurality of beams from the laser source and switch each of the beams to one of the modulator arms in order to illuminate each modulator with a sequence of colors during each frame. During the course of a frame, each of the colors becomes incident upon the modulator. The projection system disclosed herein can provide a cost-effective, efficient true digital projection display system with high resolution and high brightness.

Abstract: An image projection system comprises a laser source that generates a series of periodic pulses having substantially uniform energy content, a spatial light modulator, and a modulator driver synchronized with the laser pulses so that transition intervals of the modulator elements occur in an interpulse period between first and second states of the modulator elements. Because the pulses are substantially equal in energy, and the transitions of the modulator elements occur in interpulse intervals, the collective energy delivered to any pixel in the system described herein during the period of one frame is a direct function of the number of pulses, which can be accurately controlled in a digital manner.

Abstract: A progressive scan architecture for displaying a two-dimensional image by alternately scanning two or more laser beams, one after the other with a time delay between adjacent beams. The beams are arranged to become incident upon a polygon scanner in a row with an approximately uniform spatial separation and an approximately equal angle between adjacent beams. The polygon scanner scans horizontally and a galvanometer-driven mirror scans vertically. Adjacent lines are progressively scanned in sequence from top to bottom, which advantageously reduces or eliminates psycho-visual effects and is tolerant of non-linearities in the vertical scanner, allowing use of a low-cost galvo mirror. Typically, the beams in the row are arranged in pairs, and only one beam from each pair will be scanning at any one time.

Abstract: A display system includes blue, green, and red laser light sources and light shaping devices which receive the laser light from the laser light sources and shapes the light into a number of approximately identical beamlets. The beamlets are modulated individually and the modulated beamlets are combined. The combining results in an output of beamlets, each of which comprises three input beamlets of each of the colors red, green, and blue. The resultant beamlets can then be scanned onto a display screen.

Abstract: A fiber optic coupler for coupling an asymmetrical beam such as provided by a laser diode into a fiber optic cable. The coupler comprises at least one fiber optic cable having a longitudinally-formed approximately flat entrance facet and a cylindrical curved reflective surface formed on a first end. The curved reflective surface defines a line focus proximate to the entrance facet. A support structure situates the entrance facet proximate to the laser diode so that the line focus is approximately aligned with the narrow output aperture of the laser diode. The fiber optic cable may have any cross-section, such as circular, rectangular, or square. The fiber optic cable also includes a main body for receiving and transmitting the coupled laser radiation, and an output end having an approximately flat exit facet for outputting the laser radiation.

Abstract: A fiber optic coupler for coupling an asymmetrical beam such as provided by a laser diode into a fiber optic cable. The coupler comprises at least one fiber optic cable having a first end including a tapered section that has an approximately flat coupling facet for receiving the asymmetrical beam and an approximately flat tapered surface adjacent to the coupling facet for reflecting the rapidly diverging radiation, a main body for receiving and transmitting the reflected laser radiation, and an output end having an approximately flat output facet. A support structure situates the coupling facet proximate to the laser diode. A second, approximately flat tapered surface may be formed in the tapered section opposite the first tapered surface. The fiber optic cable may have any cross-section, such as circular, rectangular, or square.

Abstract: A two-metal grating is produced by vacuum depositing a first dielectric cing upon a separation layer formed upon a mandrel; then depositing a first optically opaque metallic layer, etching the layer to form stripes; then vacuum depositing a second optically opaque film; then electroforming a backing structure and separating the dielectric coating from the separation layer on the mandrel to form a free-standing grating structure having a smooth surface. This structure can then be affixed to a metallic mirror. A buried phase grating can also be fabricated by additionally depositing a second dielectric layer and a third metallic layer.

Abstract: A flexible light conduit which preserves the coherence of a transmitted beam. Several conduit elements having optical elements mounted inside each one are connected together to form a chain. Each conduit element is tiltably coupled to each adjacent conduit element in the chain. The optical elements may be refractive or reflective. The conduit preserves the spatial coherence properties of the beam so the input image is reimaged at a distant place, having passed through the series of relay optical elements through the angles permitted by the coupling members.

Abstract: An optical element having a thin, transparent plate containing a plurality of shallow cooling channels, and a transparent substrate immediately behind the plate with a plurality of inlet and exhaust ducts underlying and in fluid communication with coolant being circulated through the cooling channels of the plate. In use, the optical element may be configured as a beam splitter, mirror, or aperture sharing device by applying a coating that is at least partially reflective to the face plate of the element. Alternatively, if used as a window or refractive element, the above cooling structure can be applied to both faces of the element. Optical distortion can be further reduced by using a coolant having a refractive index matching that of the substrate.

Abstract: A mirror or antenna apparatus having individual petal segments, each of a complex shape, mated with a central hub assembly. Registration pads are provided on the hub assembly to align the petal segments with respect to the hub and each other. Electrical actuators provide fine tuning adjustments in the order of microns.

Abstract: An infrared scene projector has a cathode ray tube with a display screen coated with a luminescent phosphor material that produces radiation in the infrared spectrum when excited by the electron beam. The desired screen images are generated electronically, the screen is scanned by the cathode ray beam, and the intensity of the beam is modulated by the signal from the image generator.