Abstract: A multimode optical fiber is used in a confocal light-collection arrangement. A confocal aperture is supported in intimate proximity with respect to the first end of the fiber, preferably within two core diameters from the first end of the fiber. In the preferred embodiment, the confocal aperture is formed directly onto the first end of the fiber using, for example, photolithography or photoablation of a thin metallic film adhered directly to the light-collection end of the multimode fiber.

Abstract: A combined optical diffuser and light concentrator uses a layer of optically transmissive material having a first surface to receive light at a range of angles of incidence and a second surface from which the light emerges at a range of angles of emergence, the second surface including a relief pattern featuring a multiplicity of minute projections, the shape and distribution of the projections resulting in diffused light at a range of angles of emergence narrower than the range of angles of incidence. The projections may be produced in accordance with various techniques, including the processing of a photoresist layer exposed to a random speckle pattern or microlithography, including e-beam/x-ray sources.

Abstract: Laser band-pass filter and/or band-reject filters are located at the end of an optical measurement probe by placing an appropriate Bragg grating proximate to the tip, and within, one or both of the optical fibers that make up the probehead. Thus, where an optical fiber is used to carry excitation energy of a nominal wavelength to a sample, the distal tip of this fiber will have included therein an optical filter to selectively pass energy of the nominal wavelength. Similarly, where an optical fiber is employed to carry stimulated emission from the sample to an analytical instrument such as a spectrometer, this fiber will have included within it at its distal tip an optical filter to selectively reject energy associated with the nominal wavelength.

Abstract: Apparatus for gathering a frontal facial image of an individual observing a display area includes a light-conductive waveguide, transferring the image from a first light-redirecting region to a second light-redirecting region to output the image. The element is supported at least partially in front of the display, such that the input region overlies the display area, and all portions of the element overlying the display area, including the input region, are sufficiently transparent so as not to substantially interfere with the individual's observation of the display. In a preferred embodiment, at least the input region is a holographically derived optical grating, and the element is a transparent panel constructed of glass and/or plastic.

Abstract: A lighting assembly includes an on/off source of light and an optical diffuser characterized in that it receives light from the source and emits it in a desired viewing direction, but with underlying surfaces being at least diffusely visible therethrough. Thus, in an automotive or other vehicular application, the surface may be a body panel, the color of which may be visibly evident through the diffuser panel, thereby enhancing desired aerodynamic/styling characteristics. The source of light preferably comprises one or more semiconductor devices such as light-emitting diodes, and the optical diffuser is holographically recorded and provide high transmission and low backscatter to shape the emitted light in addition to its redirection in accordance with a desired beam profile or cross section.

Abstract: The present invention is a laser protection window for protection from uncontrolled laser illumination. This laser protection window includes a holographic optical element forming a reflection hologram at the wavelength of the expected laser threat. A set of channel plates opaque to the expected laser threat wavelength are disposed at right angles to the holographic optical element in order to block laser illumination arriving outside the cone of protection of the holographic optical element. These channel plates may be vertically disposed to provide protection against mostly horizontally disposed laser threats. In alternative embodiments, the channel plates include both horizontally and vertically disposed plates or plates disposed in polygonal cross section to cover the entire area of the laser protection window.

Abstract: An optical spectrograph utilizes a plurality of holographic transmission optical gratings operative to receive an incoming source of light to be analyzed and diffract the light such that different spectral components impinge upon spatially separated regions of an opto-electronic detector. Various grating configurations are disclosed, including a physical stack of gratings conducive to extreme compactness, as well as a spaced-apart configuration used to preclude spectral cross talk in certain configurations. Diverging light emerging from a fiber-optic bundle is collimated by a first lens assembly prior to passing through the gratings, and a second lens assembly is used to focus the diffracted light onto the detectors, preferably in the form of a two-dimensional CCD array.

Abstract: A narrow bandwidth bandpass filter having high transmission efficiency for the passband and excellent out-of-band attenuation employs a transmission holographic grating sandwiched between the oblique faces of a pair of right angle glass prisms. An incoming laser beam to be filtered is incident normal to one of the prism faces so as to intersect the holographic grating at about 45.degree.. The grating frequency is such as to diffract light of the transmission wavelength through substantially 90.degree. so that it exits the cube formed by the two prisms from the right angle face of the second prism. The out-of-band wavelengths of the incident beam are either transmitted unaffected through the grating or diffracted at a different angle than the light of the transmission wavelength.

Abstract: A holographic diffuser for use in conjunction with a back-lit flat-panel display and a source of illumination in the form of one or more tubular lamp segments is recorded so as to receive light from the lamp segments and scatter it preferentially along a plane perpendicular to the axis of the bulbs. In a back-lit display having vertically oriented tubular lamps, the diffuser scatters substantially more in the horizontal dimension, thus filling in the gaps of light intensity between the bulbs, which would otherwise be viewed by an observer, as with conventional diffusers. The high aspect ratio diffusers of the present invention are preferably formed by projecting coherent radiation through a mask having dimensions functionally related to the desired final aspect ratio, with an optional collimating lens being used to project that mask to infinity. A contact exposure process is also described.

Abstract: An optical spectrograph utilizes a plurality of holographic transmission optical gratings operative to receive an incoming source of light to be analyzed and diffract the light such that different spectral components impinge upon spatially separated regions of an opto-electronic detector. Various grating configurations are disclosed, including a physical stack of gratings conducive to extreme compactness, as well as a spaced-apart configuration used to preclude spectral cross talk in certain configurations. Diverging light emerging from a fiber-optic bundle is collimated by a first lens assembly prior to passing through the gratings, and a second lens assembly is used to focus the diffracted light onto the detectors, preferably in the form of a two-dimensional CCD array.

Abstract: Methods of recording and using holographic diffusers are disclosed for use with edge-lit backlight assemblies for transmissive flat-panel displays such as LCDs. When the holographic diffuser is supported against a surface of a backlight-emitting substrate it is operative to scatter the light in the direction of the display panel largely independent of angle of incidence. The recording methods may be used to produce both transmissive- and reflective-type diffusers, which may be employed simultaneously. In one embodiment a transmissive diffuser is used with a reflector and a cholesteric liquid crystal (CLC) polarizer. In this configuration, scatter lobes exhibiting the correct circular polarization are passed by CLC polarizer, whereas radiation of the opposite handedness is redirected toward the reflector, which converts the handedness into the form passable by the CLC polarizer.

Abstract: A holographic probe facilitates the measurement of radiative effects such as Raman scattering or fluorescence of a remotely disposed sample. Improving upon prior-art techniques, the probe teaches a substantially in-line path between the sample and an output optic wherein a narrowband reflective element, preferably holographically recorded, is used to fold excitation energy from an illumination path into the collection path and reject any Rayleigh scattering received from the sample. The improved configuration further allows a dispersive filtering element to be placed in the illumination path, which may be used in conjunction with spatial filtering to reject non-excitation wavelengths.

Abstract: The present invention is a technique for construction of a laser protection window providing broadened angular protection. Plural modulated index of refraction filter elements are constructed to reflect incident light at a predetermined laser threat wavelength over a cone of protection. The plurality of modulated index of refraction filter elements are disposed in tandem at angles to a direction of primary view through the laser protection window which are symmetrical with respect to the direction of primary view. In a first embodiment, a first optional modulated index of refraction filter element is disposed perpendicular to the direction of primary view; the other modulated index of refraction filter elements are disposed in pairs at opposing angles to the direction of primary view. In an alternative embodiment, the angled modulated index of refraction filter element plates are formed of angled segments.

Abstract: Holographic optical elements relatively free of unwanted, secondary fringes are produced using light having a limited coherence. A photosensitive material of a predetermined thickness records the interference between two beams of light. The mutual coherence of the two illumination beams is sufficiently great to form high contrast interference fringes within some portion of the photosensitive medium. The mutual coherence is limited to prevent the formation of high contrast interference with reflections from the various parts of the construction optics. The two illumination beams may be incident from opposite sides of the photosensitive medium forming a reflection holographic optical element or from the same side of the photosensitive medium forming a transmission holographic optical element. A laser generates the first illumination beam. Control of the mutual coherence may be by passing the first illumination beam through a moving diffuser plate or by varying the wavelength of the laser during the exposure.

Abstract: Holographic optical elements relatively free of unwanted, secondary fringes are produced by passing the light beam from a laser through a rotating diffusing plate to generate a beam of light having a very limited coherence length and a spatial coherence which changes over a period of time. A photographic emulsion having a mirror supported on its reverse side is illuminated by the beam and interference occurs between this primary illumination and illumination reflected from the mirror, creating fringes. No other interference fringes are formed because of the lack of coherence between secondary reflections and other rays of the incident beam. The rotation of the diffusion plate time averages out speckle patterns which would otherwise occur. Alternatively, the illuminating beam has a high degree of spatial coherence but its temporal coherence is reduced and varied over a period of time by changing the wavelength of a tunable-dye laser.

Abstract: Holographic optical elements relatively free of unwanted, secondary fringes are produced by passing the light beam from a laser through a rotating diffusing plate to generate a beam of light having a very limited coherence length and a spatial coherence which changes over a period of time. A photographic emulsion having a mirror supported on its reverse side is illuminated by the beam and interference occurs between this primary illumination and illumination reflected from the mirror, creating fringes. No other interference fringes are formed because of the lack of coherence between secondary reflections and other rays of the incident beam. The rotation of the diffusion plate time averages out speckle patterns which would otherwise occur.Alternatively, the illuminating beam has a high degree of spatial coherence but its temporal coherence is reduced and varied over a period of time by changing the wavelength of a tunable-dye laser.

Abstract: The Raman scattering detector of this invention includes a source of collimated monochromatic illumination, a cube formed of two right angle prisms, a holographic optical element disposed between the prisms, a concentrating lens, a focusing lens and one or more photo detectors. The illuminating beam passes through the cube and is concentrated by the concentrating leans to a sample. Scattered light returned to the concentrating lens is substantially collimated upon return to the cube. The holographic optical element diffracts light at desired Raman wavelengths approximately 90 degrees without substantially affecting the original wavelength. The holographic optical element further disperses light at desired Raman wavelengths permitting them to be separated. The diffracted and dispersed wavelengths are focused on one or more detectors by the focusing lens.

Abstract: The present invention is a laser protection visor. This visor has an ellipsoidal shape. The major axis of the ellipsoid falls on the line connecting the user's eyes. The foci least as far apart as the expected interpupillary distance of the user. The visor has a modulated index of refraction reflection filter disposed thereon having a rejection bandwidth including the wavelength of the expected laser threat. The ellipsoidal shape minimizes the maximum rejection angle needed to prevent laser radiation from reaching either eye. This in turn minimizes the needed rejection bandwidth and thus increases the visual see through at other wavelengths. In the preferred embodiment the modulated index or refraction layer forming the reflection filter is formed of a holographic optical element constructed by capturing an interference pattern in a photosensitive medium.

Abstract: The present invention is an adaptive laser protection device which adaptively forms a reflection holographic optical element to reflect away incident laser radiation. The laser protection device includes a layer of a nonlinear optical material which has an index of refraction varying with light intensity, a transparent layer having a depth greater than the coherence length of the expected ambient illumination and less than the coherence length of the expected laser radiation, and a partially reflecting layer on the far surface of the transparent layer. Laser radiation incident on the laser protection device forms an interference pattern in the nonlinear optical material between directly incident light and light reflected from the partially reflecting layer. This interference pattern within the nonlinear optical material causes the formation of a holographic optical element due to varying indices of refractions.

Abstract: The present invention is a manner of constructing holographic optical elements for use in laser eye protection. A photosensitive layer, preferably formed of dichromated gelatin, is disposed on a transparent supporting substrate with a reflecting surface conformal to the outer surface of the photosensitive layer. The photosensitive layer is exposed with light from a laser point source. The photosensitive layer records the interference patterns between light incident directly from the laser point source and light reflected from the reflecting surface. The photosensitive layer is developed to form a holographic optical element. When this holographic optical element is disposed before the eye, with the center of the eye located at a point equivalent to the location of the laser point source, laser light directed toward the center of the eye is diffracted by the holographic optical element and effectively reflected away from the eye.