Abstract: By applying a photonic signal to a microresonator that includes a photonic bandgap delay apparatus having a photonic band edge transmission resonance at the frequency of the photonic signal, the microresonator imparts a predetermined delay to the photonic signal. The photonic bandgap delay apparatus also preferably has a photonic band edge transmission resonance bandwidth which is at least as wide as the bandwidth of the photonic signal such that a uniform delay is imparted over the entire bandwidth of the photonic signal. The microresonator also includes a microresonator cavity, typically defined by a pair of switchable mirrors, within which the photonic bandgap delay apparatus is disposed. By requiring the photonic signal to oscillate within the microresonator cavity so as to pass through the photonic bandgap delay apparatus several times, the microresonator can controllably impart an adjustable delay to the photonic signal.

Abstract: The method and apparatus for measuring the transmittance of blood within a retinal vessel detects the intensity of light reflected from illuminated portions of an eye, including the retinal vessel and background fundus, and adjusts the corresponding intensity signals to compensate for reflections from the retinal vessel. In particular, the transmittance measuring method and apparatus constructs an intensity profile function based upon the intensity signals. As a result, the intensity profile function approximates the intensity of light transmitted through the retinal vessel as a function of retinal vessel position. During the construction of the intensity profile function, the transmittance measuring method and apparatus can compensate for at least some of the reflections of light from the retinal vessel which occurred prior to propagation of the light through the retinal vessel, thereby increasing the accuracy with which the transmittance of blood within a retinal vessel is measured.

Abstract: A waveguide hologram illumination system is based on thin substrate waveguides bearing a hologram on the surface through which light is diffracted out. A light source is optically coupled to the waveguide such that light emitted from the source is caused to propagate along the waveguide, being diffracted out at intersections with the surface of the waveguide on which the hologram is formed. The selective emission through the hologram can be advantageously used to illuminate display holograms or spatial light modulators. Provisions are made for rendering the amount of light emitted through the hologram uniform along the length of the hologram.

Abstract: The method and apparatus for measuring the oxygen saturation of blood within a retinal vessel illuminates the retinal vessel with light having a combination of wavelengths selected to reduce the error in the measured blood oxygen saturation. The oxygen saturation measuring method and apparatus illuminates a retinal vessel with light having the selected combination of wavelengths. For example, the oxygen saturation measuring method and apparatus can illuminate the retinal vessel with light having a first wavelength between 460 nm and 503 nm, a second wavelength between 600 nm, and 770 nm and a third wavelength between 770 nm and 1000 nm. The oxygen saturation measuring method and apparatus then measures the transmittance of the blood within the retinal vessel in response to the illumination at each of the selected wavelengths.

Abstract: A photonic signal is applied to a photonic bandgap structure having a photonic band edge transmission resonance at the frequency of the photonic signal and having a photonic band edge transmission resonance bandwidth which is at least as wide as the bandwidth of the photonic signal. When a photonic band edge transmission resonance is matched to the photonic signal which is being transmitted, a controllable delay is imparted to the photonic signal without significantly altering the photonic signal itself.

Abstract: An instrument and a method are provided for determining the concentration of at least one species in a substance. The instrument and method can be used to identify and distinguish among various degrees of contamination of motor oil, diesel fuel, and hydraulic fluid by water, ethylene glycol, wear particles, and loss of anti-oxidants. The instrument includes a broad band light source, such as a tungsten filament incandescent lamp, which is very inexpensive and reliable. A fiber optic link is provided to a detector that receives and discriminates among optical spectral transmissions through the fiber optic. Discrimination circuitry is provided for evaluating the transmission and providing a readout that indicates the quality of the fluid. The instrument is suitable for in situ determination of oil quality.

Abstract: A display device which is capable of producing a plurality of different views of an image simultaneously is provided. The display includes an array of semiconductor devices with an electro-optical material disposed over the array of semiconductor devices. The semiconductor devices include electrodes which are selectively activated to form refraction gratings in the electro-optical material. Each of the semiconductor devices also includes a processor layer which can determine a refraction grating which is necessary for generating a predetermined number of discrete images which are visible from a predetermined number of different vantage points or viewer positions. Since a different image is provided to each eye, the viewer is provided with a perception of depth such that a three-dimensional image is provided. In addition, since different images or at least different image perspectives are provided to different points, horizontal and/or vertical parallax of the display is attained.

Abstract: A waveguide hologram illumination system is based on thin substrate waveguides bearing a hologram on the surface through which light is diffracted out. A light source is optically coupled to the waveguide such that light emitted from the source is caused to propagate along the waveguide, being diffracted out at intersections with the surface of the waveguide on which the hologram is formed. The selective emission through the hologram can be advantageously used to illuminate display holograms or spatial light modulators. Provisions are made for rendering the amount of light emitted through the hologram uniform along the length of the hologram.

Abstract: A multimode waveguide having a small thickness has light coupled to the side of the waveguide in order to provide a multimode operation of the waveguide for providing a continuous pattern of totally internally reflected light which is utilized to reconstruct holographic images from a holographic emulsion placed on a surface of the waveguide. This waveguide structure for reconstructuring a hologram has the capability of providing highly efficient hologram reconstruction while using ordinary light sources and is able to use beam diameters greater than the thickness of the waveguide.

Abstract: A switch device which includes a magnet movable within a passageway. A wire coil is provided about the passageway such that, as the magnet moves into the coil, a current is induced, thereby providing a signal pulse. The switch can be utilized for sensing changes in inertia, with a stopper opposing movement of the magnet unless the magnet imparts sufficient force against the spring biased stopper to allow the magnet to move along the passageway. The biasing force of the stopper can be adjusted to adjust the amount of force, acceleration or deceleration required for actuating the switch. The switch may also be utilized without the spring-biased stopper, with the magnet preloaded with a spring or weight, such that the switch automatically operates upon removal of a safety pin.

Abstract: A multimode waveguide having a small thickness has light coupled to the side of the waveguide in order to provide a multimode operation of the waveguide for providing a continuous pattern of totally internally reflected light which is utilized to reconstruct holographic images from a holographic emulsion placed on a surface of the waveguide. This waveguide structure for reconstructuring a hologram has the capability of providing highly efficient hologram reconstruction while using ordinary light sources and is able to use beam diameters greater than the thickness of the waveguide.

Abstract: A new polyethylene glycol derivative (PEG) having the property of not being destroyed by water and also being able to retain reactivity in water and selectively react with amine groups. Also provided is a process for modifying organic or polymer surfaces in water by connecting PEG derivatives to exposed amine groups which provides a process whereby there is efficient linking to organic or polymer surfaces in water by use of the PEG derivatives.

Abstract: A system to produce interconnections between a planar input array and a planar output array using a holographic planar array made by a single exposure or multiple exposures of a photosensitive medium incorporated therein at each of M.times.N positions in said holographic planar array to store the weighted interconnections to connect each input of the O.times.P input array to any one or any combination of outputs in the R.times.s output array in parallel with the strength of connection for each output being determined by the weighting factors as stored in said holographic planar array unadjusted or as adjusted by one or more modulating devices incorporated therein when the optically aligned system is illuminated from any one or any combination of V.times.W sources each of which produces a beam of electromagnetic radiation singular in time or any combination of such V.times.W sources in parallel with each such source producing a different wavelength or any combination of such V.times.

Abstract: An infrared achromatic waveplate structure having a cadmium sulfide (CdS) plate and a cadmium selenide (CdSe) plate aligned with each other so that the fast axis of the plates are perpendicular to each other, this structure provides a desired retardance of a first orthogonal polarization component with respect to a second orthogonal polarization component of an incident light beam. The thickness of the plates are in a ratio between 0.8:1 and 0.9:1 (CdSe:CdS), an achromatic response with a substantially constant retardance is provided in a wavelength range from 3 to 11 microns. A desired amount of retardance is available by adjusting the thickness of the two plates as long as the ratio of the thicknesses is maintained within the recited value. In particular a quarter wave net retardance of an incident light beam operating between 3 and 11 microns is provided when the cadmium sulfide plate is 1.25 millimeters and the cadmium selenide plate is 1.0666 millimeters.

Abstract: An improved fabrication of superconducting films is disclosed whereby a multi-phase Y-Ba-Cu-O compound is utilized. The film is formed by sputtering of a target material consisting of the superconducting 123 phase Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7 onto the green 211 phase Y.sub.2 BaCuO.sub.5. After annealing, the superconducting characteristics, of the formed film, in terms of transition width and T.sub.c, are improved over those using other oxide compounds as substrates.