Abstract: A night vision system 10 is provided for detecting objects at relatively low visible light levels. The system 10 includes an infrared light source 14. The system 10 further includes a thin sheet optical element 16 extending along a first axis 27 receiving light from the infrared light source 14 and reflecting the light generally in a first direction. Finally, the system 10 includes an infrared camera for receiving the light reflected off objects in the environment and generating a video signal responsive to the received light.

Abstract: An optical element, a lighting system utilizing the optical element and a method of manipulating light from a source to provide an illumination pattern suitable for use in a night vision system and exterior lighting applications is disclosed. The optical element has an input surface and an output surface disposed at approximately perpendicular to the input surface. A stepped surface angles between the input surface and the output surface intersecting the light inside the optical element. Multiple facets are formed in the stepped surface to reflect the light towards the output surface. The input, stepped and output surfaces are arranged such that the light reflects only from the stepped surface. The optical element has a rectangular shape in one embodiment and a wedge shape in a second embodiment.

Abstract: An on-board gas composition sensor is disclosed for monitoring oxygen content levels in the exhaust gas of an internal combustion engine. The gas composition sensor includes a light source for generating excitation light, e.g. in the 350-525 nm wavelength range. A sensor body of porous high-temperature fluorescent inorganic oxide ceramic exposed to the exhaust gas emits an optical fluorescence signal responsive to oxygen content in the exhaust gas upon exposure to the excitation light at 400.degree.-650.degree. C. A florescence detector receives the optical fluorescence signal from the sensor means and generates an exhaust gas oxygen content output signal in response. Fiber-optic cable can be employed for transmitting excitation light to the sensor body from a remotely located light emitter. The same or a separate fiber-optic cable can transmit the optical fluorescent signal from the sensor body to the fluorescence detector also at a remote location.

Abstract: A crystalline silicon carbide film is grown on a heated crystalline silicon substrate by laser ablation of a pure carbon target. For substrate temperatures during deposition above 1000.degree. C. and single crystal silicon substrates the resulting SiC film is expitaxially oriented with respect to the substrate. Films of stoichiometric SiC are grown up to thicknesses of about 4000.ANG.. These films grow on top of the silicon substrate and whereas the source of carbon for the film is from the ablation plume of the carbon target the source of the silicon is from the substrate. By using a method of alternate ablation of a pure carbon and a pure silicon target, similar epitaxial films can be grown to thicknesses in excess of 1 .mu.m with part of the silicon being supplied by the ablation plume of the silicon target.

Abstract: A ferrofluid controlled switch for a light pipe has a light pipe having a first index of refraction, a fluid responsive to a magnetic field having a second index of refraction, and an enclosure concentrically located around at least a portion of the light pipe for retaining the fluid such that the fluid is capable of assuming two configurations, one adjacent to the light pipe and one separate from the light pipe. A controllable magnetic field device such as a permanent magnet or wire coils are used to transfer the magnetically responsive fluid between said two configurations to reduce the output of the light pipe when the fluid is adjacent to the light pipe.

Abstract: An electrophoretic light switch is provided for controlling light in a light pipe having a transparent inner conductor, an outer conductor and a solution containing charged particles. Light is absorbed by the solution when the particles are attracted to the inner conductor causing the light intensity in the light pipe to be reduced.