Abstract: An optical element including a substrate which is generally transparent to infrared radiation in a wavelength range of 5-16 &mgr;m, a pigment disposed in the substrate in an amount that does not generally decrease transmission of the infrared radiation, the pigment being generally non-transmissive to at least one of visible and ultraviolet light, the pigment being reactable with the substrate over time to create a reaction product which can decrease transmission of the infrared radiation, and a protective agent disposed in the substrate in an amount that does not generally decrease transmission of the infrared radiation and which generally prevents creation of the reaction product which can decrease transmission of the infrared radiation. The optical element may be a lens for a passive infrared detector assembly, for example.

Abstract: An illuminator system (16) for an interior cabin (12) of a vehicle (14) includes a light source (72) and a beam-forming optic (100) that is optically coupled to the light source. The optic (100) forms an illumination pattern (22) that is directed forward of the vehicle (14). A housing (58) supports the beam-forming optic (100) along a roofline (47) and window perimeter (48) of the vehicle (14).

Abstract: An infrared transparent optical element for use as an optical window for an infrared imaging camera includes an infrared transparent substrate, an antireflection film, and a protective film of a polymer material. The infrared transparent substrate has first and second major surfaces opposite each other, and the antireflection film is disposed on each of the first and second major surfaces of the substrate. The protective film is on an outer surface of the antireflection film on the first major surface of the substrate.

Abstract: A dioptric projection objective for forming an image of an object, includes a plurality of lenses arranged in an optical path between the object and the image. At least two lenses of the plurality of lenses have respective mutually adjacent lens surfaces which are aspheric to define a double asphere, and the plurality of lenses include positive lens groups, each having at least two lenses, and negative lens groups each having at least two lenses. In addition, a dioptric projection objective having an image side numerical aperture that is greater than or equal to 0.75 for forming an image of an object, includes a plurality of lenses arranged in an optical path between the object and the image, with at least two of the lenses of the plurality of lenses having respective mutually proximal lens surfaces which are aspheric to define a double asphere.

Abstract: Unfinished lenses, semi-finished lens including optical coatings or a transmission altering layer and methods of manufacturing are described. The unfinished lens includes an optical coating and a surface configured to receive a curve. Non-prescriptive and prescriptive lenses can be made by the method.

Abstract: A lens for laser cutting devices, with improved heat transfer properties, and more particularly a lens having a radius R1+R2, the lens comprising a lens body having a radius R1 and a radial outwardly extending flat flange portion having a radius R2, wherein the ratio of R1/R2 is chosen such that the heat transfer is optimized.

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: The present invention is directed to a transparent medium incorporating the oxidative polymerization product of 3-hydroxykynurenine, a synthetic version of the yellow-to-brown pigment that occurs in the ocular crystalline lens with age. Because this coloration in the ocular lens is believed to offer photoprotection to the retina, it may represent an ideal sun lens filter with an optical transmission spectrum that is compatible with the psychophysical and neuro-physiological characteristics of the vision system.

Abstract: The present invention is directed to a three-dimensional memory apparatus for storing information in a volume comprising of an active medium. The active medium is capable of changing from a first to a second isomeric form as a response to radiation of a light beam having an energy substantially equal to a first threshold energy. The concentration ratio between a first and a second isomeric form in any given volume portion represents a data unit. The active medium in the memory apparatus comprises of diarylalkene derivatives, triene derivatives, polyene derivatives or a mixture thereof. The invention is further directed to means for reading the data units from the isomeric states of the active medium in different portions of said active medium where the two isomeric forms have a substantially different absorption coefficient for absorbing energy of a second threshold energy. Reading may also be carried out by measuring the scattering pattern of the two isomeric forms.

Abstract: The present invention relates to a method for designing an achromatic lens and a lens according to the design. The invention provides a lens that makes use of the differences in the index of refraction of ZnSe and ZnS in the mm-wave and IR wavebands to minimize the differences in focal position between the two wavebands. This lens train can be used in conjunction with a dual-band focal plane array to simultaneously focus two wavebands on a common focal plane and thus provide for simultaneous imaging in both wavebands.

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the. reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: A system and method for simultaneous imaging of both infrared and millimeter wave radiation. The novel optical system (10) includes a primary mirror (20), a Mangin secondary mirror (30) positioned to receive energy reflected from the primary mirror (20), and an immersion lens (40) for focusing energy received from the Mangin mirror (30). In the illustrative embodiment, the primary mirror (20) and Mangin mirror (30) are arranged in a Cassegrain configuration. Central to this invention is the use of a negative power refractive Mangin mirror (30) as the Cassegrain secondary mirror, so that the field curvature of the secondary mirror (30) and immersion lens (40) can be made to cancel. The immersion lens (40) effectively decreases the wavelength of the millimeter wave radiation, allowing a smaller detector to collect the same amount of radiation as would a larger detector in air.

Abstract: An antireflection substrate comprising a substrate which is transparent to ultraviolet and vacuum ultraviolet rays in the wavelength region from 155 nm to 200 nm and a mono-, bi- or tri-layer antireflection film formed on at least one side of the substrate, wherein the refractive index and the physical thickness of the antireflection film at the center wavelength &lgr;0 of the wavelength region of ultraviolet or vacuum ultraviolet light which needs antireflection satisfy particular conditions, and an optical component for a semiconductor manufacturing apparatus and a substrate for a low-reflection pellicle which is the ultraviolet and vacuum ultraviolet antireflection substrate

Abstract: A night vision system, suitable for vehicular use, including an infra-red detector mounted on a vehicle, a display mounted on the vehicle, a single-element lens mounted upstream of the infra-red detector so as to direct light from a scene onto the infra-red detector, and circuitry operative to receive a detector output from the infra-red detector and to provide an image output based on the detector output to the display. The system is suitable for applications other than vehicular use, where a comparatively narrow field of view is to be imaged.

Abstract: Dual band millimeter-wave and infrared anti-reflecting coatings are presented, which enhance the passage of millimeter-wave and infrared radiation into a substrate material. A substrate is coated with a quarter-wave coating of an infrared anti-reflecting material followed by a quarter-wave coating of a millimeter-wave anti-reflecting material followed by a second quarter-wave coating of an infrared anti-reflecting material. The second infrared anti-reflecting coating enables incident infrared radiation to pass into the millimeter-wave anti-reflecting material, while minimizing reflection. The first infrared anti-reflecting coating enables incident infrared radiation from the millimeter-wave anti-reflecting material to pass into the substrate material, while minimizing reflection. The millimeter-wave anti-reflecting coating enables incident millimeter-wave radiation to pass into the substrate material, while minimizing reflection.

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: The invention provides a method of making a <194 nm wavelength calcium fluoride crystal optical lithography element for transmitting wavelengths less than about 194 nm along an optical axis with minimal birefringence by providing an optical element optical calcium fluoride crystal with an input face {100} crystal plane and forming the input face {100} crystal plane into an optical lithography element surface of an optical lithography element having an optical axis, with the optical axis aligned with a <100> crystal direction of the optical calcium fluoride crystal. In a preferred embodiment, the below 194 nm transmitting optical element is a <100>oriented calcium fluoride lens. In a preferred embodiment, the below 194 nm transmitting optical element is a <100> oriented calcium fluoride beam splitter.

Abstract: A radiation source assembly and transducer incorporating same are suitable for use in measuring spectral absorption properties of a substance to be analyzed, such as a gas. The radiation source assembly has an optical axis. A measuring radiation source provides radiation in the direction of the axis and a reference radiation source provides radiation in the direction of the axis. An optical diffuser is spaced from the radiation sources along the axis. Radiation from the measuring radiation source and radiation from the reference radiation source are applied to the diffuser and the diffuser forms an exiting radiation beam for the assembly from the radiation of the measuring radiation source and reference radiation source. The exiting radiation beam extends along the axis.

Abstract: An infrared optical system for infrared cameras has a convex lens held by a holding member composed of a low-dispersion material that transmits infrared light. A stop for restricting light beams entering the convex lens is disposed on an object side from the convex lens. An aberration correcting plate for reducing spherical aberration is provided in the vicinity of the stop. A field flattener, the thickness of which changes along image height to offset curvature of field, is disposed on an image side of the convex lens.

Abstract: A bright wide-angle infrared lens, suitable for a wavelength band of 8 to 12 &mgr;m, having favorable imaging performances comprises, successively from the object side, a first lens L1 made of a positive meniscus lens having a convex surface directed onto the object side and an image-side surface formed aspheric, a second lens L2 made of a negative meniscus lens having a convex surface directed onto the object side, and a third lens L3 having a positive refracting power with a convex surface directed onto the object side.

Abstract: A projection exposure lens system has an object side catadioptric system, and intermediate image and a refractive lens system. The refractive lens system from its intermediate image side and in the direction of its image plane has a first lens group of positive refractive power, a second lens group of negative refractive power, a third lens group of positive refractive power, a fourth lens group of negative refractive power, and a fifth lens group of positive refractive power.

Abstract: An inspection microscope (1) having a light source (3) that emits light of a first wavelength below 400 nm for illumination of a specimen (13) to be inspected, and having an objective (11) that is composed of multiple optical components and has a numerical aperture and a focal length, and having a tube optical system (21) and an autofocus device (25) that directs light of a second wavelength onto the specimen (13), is disclosed. The inspection microscope (1) is characterized by the objective (11), which has an optical correction that eliminates the longitudinal chromatic aberrations with respect to the first and the second wavelength and whose optical components are assembled in cement-free fashion, the second wavelength being greater than 400 nm.

Abstract: A diffractive optical element, as well as an optical system incorporating the same, has a comparatively large minimum grating pitch and, hence, is easy to produce. The diffractive optical element has a diffraction grating surface and an aspherical surface formed on an identical substrate or on separate substrates. The pitch of the diffractive grating varies such that it progressively decreases radially outward from the center of the substrate and then kept constant towards the radially outer extremity of the substrate.

Abstract: An infrared transparent optical element of the invention is for use as an optical window for an infrared imaging camera. The optical element includes an infrared transparent substrate, an antireflection film, and a protective film made of a polymer material. The infrared transparent substrate has first and second major surfaces opposite to each other, and the antireflection film is formed on each of the first and second major surfaces of the substrate. The protective film is formed on an outer surface of the antireflection film on the first major surface of the substrate.

Abstract: The system according to the invention uses cutting edge technologies such as Uncooled Staring Focal Plane detector Array, Hot Pressed Polycrystal Objective Lens, Helmet Mounted Display Using Transparent Image Combiner, and Neural Network Image Colorization and Recognition to dramatically enhance the system performance and reduce the weight and cost. The helmet mounted infrared imaging system can: Detect and recognize flames, humans and other objects, Reduce the weight of the helmet components (including camera head and combiner) to less than 0.5 pounds, View simultaneously visible and invisible surroundings without hindering operations. Operate the imaging system hands-off; and Transmit the imaging data to and receive the map from a remote sight. Alternative Embodiment In an alternative embodiment, the infrared camera is mounted centered in front of the display.

Abstract: A multi-beam zoom lens for producing variable spot sizes on a photosensitive medium from a plurality of individually modulated light sources wherein each light source emits a light beam parallel to each of the other light sources and parallel to an optical axis and wherein a numerical aperture of each of said light beams is greater than 0.125, comprising an afocal zoom lens (10). The afocal zoom lens comprises a first moving group of lenses (13), a second group of moving lenses (14), and a third group of moving lenses (15). A constant barrel length of the afocal zoom lens is less than 160 mm and the zoom lens has a constant distance from the light sources to the photosensitive medium of less than 180 mm. The zoom lens has an afocal magnification of at least 45% across a zoom range.

Abstract: An image reading apparatus comprises a light source for illuminating an original, an imaging optical system for forming an image of the illuminated original on the focal plane of the system, and a sensor unit arranged in front of the focal plane. At least two infrared cut filters are arranged on the optical path between the light source and the sensor unit. Those infrared cut filters show respective spectral characteristics that are different from each other. The imaging optical system typically comprises a plurality of lenses and the infrared cut filters are arranged on at least two of the respective surfaces of the lenses.

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: High-density polyethylene (HDPE) is used as a coating for optical elements operating in transmission in the infrared spectrum, which are made up of a material other than polyethylene, such as hygroscopic salt, semiconductor materials, fluorides, chalcogenides, silver halides, and others, so as to exploit the optical properties of HDPE, at the same time keeping the thickness reduced.

Abstract: An infrared refractive lens triplet having color correction properties for radiation within the 3 to 12 micrometer spectral band for use with a quantum well detector for simultaneous dual band imagery. In certain embodiments of the invention, two widely spaced triplets form a Petzval-type objective lens. Each lens triplet is made up of a negative zinc sulfide lens, a positive zinc selenide lens, and a negative gallium arsenide lens coaxially positioned along a chief ray of the lens system.

Abstract: A display apparatus includes an IR or other light source that produces light at a first wavelength that is modulated according to a desired image. The modulated light is then applied to a phosphor that converts the light to a second wavelength in the visible range. In one embodiment, the image source is a scanned light beam display that scans an IR light beam onto an image intensifier tube of a night vision goggle. In other embodiments, the image source is a LCD having an IR back light or a FED panel that emits electrons directly into a microchannel accelerator plate of the night vision goggles. In still another embodiment, the image source emits visible or ultraviolet light onto a phosphor that emits light of a different wavelength in response.

Abstract: An infrared-transparent structure includes a first infrared-transparent element that is transparent to infrared radiation in the 3.6-7 micrometer wavelength range, preferably coated with a zinc-sulfide antireflective coating, and a layer of a solvent-free, infrared-transparent polymer transparent on the first infrared-transparent element. The polymer is formed of an addition-cured silicone, such as addition-cured dimethyl silicone, and a small amount of an adhesion promoter, such as 3-glycidoxypropyltrimethoxysilane. The polymer layer may either be a surface layer, or it may be used as an adhesive between the first infrared-transparent element and a second infrared-transparent element.

Abstract: A microscope objective lens of the present having, in the order from the object side, a first lens group, a second lens group and a third lens group. The first lens group comprises a meniscus lens with its concave surface facing the object side and a plurality of cemented lenses, and has a positive refractive power on the whole. The second lens group comprises a plurality of cemented lenses and has a positive refractive power on the whole. The third lens group comprises a plurality of cemented lenses and having a negative refractive power on the whole, and fulfills the following conditions (1) to (3): 2.5<f1/f<5  (1) 30<f2/f<70  (2) 15<|f3/f|<30  (3) where f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f is the focal length of the whole microscope objective lens system.

Abstract: A large numerical aperture objective lens is disclosed having three lens groups. In order from the object side, these lens groups include: a first lens group of positive refractive power that is formed of two positive lens elements and an achromatic set of paired lens elements formed of a lens element of negative refractive power and a lens element of positive refractive power, respectively; a second lens group of negative refractive power; and a third lens group of positive refractive power, with the surface of the third lens group nearest the object side being convex. Specified conditions are satisfied in order to provide a compact, large numerical aperture objective lens having its aberrations favorably corrected as well as to correct for shifts of focus caused by expansion/contraction of the lens barrel with changes in temperature.

Abstract: An optical element includes an incidence surface, one or more reflecting surfaces reflecting light from the incident surface, an emergence surface, and off-axial curved surfaces causing the light to emerge from the emergence surface. At least one of the incidence surface, the emergence surface and the one or more reflecting surfaces is a surface having diffracting action. The surface having the diffracting action is a curved surface.

Abstract: In a preferred embodiment, an infrared optical position detection system, including: an infrared emitter to emit infrared radiation toward an object; a receiver to receive the infrared radiation scattered by the object and to determine position of the object; the receiver including a detector; and the receiver including an optical system having two and no more than two lenses.

Abstract: An infrared lens and detector system and associated method are disclosed that utilize infrared lenses to form an internal entrance pupil at which an internal aperture stop is placed to control the intensity of infrared radiation focused on the infrared detector. In more detailed respects, the infrared lens is an assembly including a first infrared lens, a second infrared lens spaced from the first lens to form a pupil between the first and second lenses, and an aperture stop disposed proximal the pupil. The aperture stop may have a fixed diameter or may have an aperture stop that is manually or automatically adjustable depending upon the intensity of the infrared radiation being viewed. Significantly, this lens assembly may be sealed for improved performance particularly in extreme conditions. In more detailed respects, the lens assembly forms a wide-angle lens and includes a diffractive surface on the second lens to reduce color aberrations and improve performance.

Abstract: A phosphate glass doped with copper in an amount of less than 2% by weight is formed to produce a lens for use on external aircraft lights. The glass attenuates infra red radiation to a degree where it does not pose a danger of temporarily blinding a pilot wearing night vision goggles yet remains visible. The glass has little appreciable effect on light transmission in the visible spectrum. Conveniently, the glass can be formed by slumping at a softening temperature against a mold to produce intricate lens shapes. In addition, the glass is able to withstand conventional toughening processes.

Abstract: A wide field of view infrared zoom lens assembly (16) having a constant F/Number. The wide field of view infrared lens assembly (16) includes a focusing component (33), a collecting component (37), an aperture stop (46), and a diffracting component (41). The focusing component (33) may include a pair of focusing zoom lenses (34, 36). The collecting component (37) may include a first collecting lens (38) and a second collecting lens (40). The focusing component (33) and the collecting component (37) may be formed from high dispersion, low index material. The aperture stop (46) may be mounted to the first collecting lens (38) to maintain a constant F/Number. The diffracting component (41) may include a diffractive surface to correct color aberrations associated with an infrared waveband. The focusing component (33) and the collecting component (37) cooperate with the diffracting component (41) to focus infrared radiation at an image plane (15) of an infrared detector (18).

Abstract: An objective lens system 10 uses Germanium lens elements including a positively-powered objective lens (A), a positively-powered intermediate lens (B) and a negatively-powered field lens (C). The field lens (C) flattens the Field curvature of the system. The intermediate lens (B) corrects astigmatism and has an aspheric surface (3).

Abstract: Multi-spectral images are detected using a refractive objective lens system. Magnesium oxide (MgO) and calcium fluoride (CaF2) lenses are used to image scenes in both the visible and infra-red (IR) spectrums. The inventors have discovered that the combination of magnesium oxide, only recently made available in a pure crystal form, and calcium fluoride can be used to fabricate an objective lens for imaging objects in both the visible and infra-red spectrums. Moreover, the combination of magnesium oxide and calcium fluoride results in a super-achromatic condition across visible and infra-red spectrums. This chromatically-corrected spectral range includes wavelengths between 0.4 and 5.9 microns which covers medium-wave IR (MWIR), short-wave IR (SWIR), and the near-IR/visible windows. Combinations of MgO and CaF2 lenses are used in different compound objective lens designs including doublet, Petzval, inverted telephoto, and telephoto arrangements.

Abstract: Methods and apparatus for generating uniform reference sources for use in calibrating multiple-detector imaging devices. In exemplary embodiments, a plano-plano reference lens is inserted at a non-focusing position in the optics path of a multiple-detector imaging device. The reference lens includes a highly polished side coated with a semi-reflective film and a rough polished side coated with an anti-reflective coating. The smooth polished side causes the detector array to see a reflected image of itself and a portion of the incoming scene energy simultaneously. The energy emitted by the detector array thus mixes with the scene energy to create a detected photon flux level which is dependent upon, but deviates in a controlled manner from, that of the scene energy alone. At the same time, the rough polished side and the thickness of the reference lens blur the detected image to eliminate scene structure and to provide a uniform photon flux level at each detector in the array.

Abstract: An infrared afocal lens assembly for providing an observed magnified IR ie scene with a field of view and a substantially less temperature dependent performance. The assembly includes a collecting lens, focusing lens subassembly movable along the optical axis to provide range focus, an intermediate focal plane, an eyepiece lens subassembly, and an aperture stop. A wide field of view lens subassembly may be used on the optical axis. All lenses are made of either GaAs or ZnS, and all lenses are single lenses only.

Abstract: Zinc sulfide and an optical component are provided that significantly reduces transmission for visible light and infrared rays of not more than 3 .mu.m in wavelength, having high transmittance for infrared rays in the wavelength range of 8-12 .mu.m, and that shields visible light. The optical component is constituted by a polycrystalline zinc sulfide sintered compact formed by hot compression molding fine zinc sulfide powder of high impurity at the temperature of 900-1000.degree. C. and the pressure of 150-800 kg/cm.sup.2. The light transmittance at the region where the thickness is 2 mm is 0% to 3% at the wavelength range of visible light, 0% to 20% at the wavelength range of 2.5-3 .mu.m, 30% to 75% at the wavelength range of 8-12 .mu.m, and 50% to 90% at the same wavelength range with the formation of antireflection coating film.

Abstract: An afocal telescope operating in the thermal infra-red waveband has a three-element objective comprising a positively-powered central lens element disposed between positively powered and negatively powered lateral lens elements, the positively powered lateral lens element being located proximal to the inter-mediate image and incorporating a hybrid surface simultaneously to correct longitudinal and field colour, and wherein one of the positively powered lens elements of the objective is made of a material having a negative temperature refractive index co-efficient and has an optical power selected to render the telescope athermal.

Abstract: A thorium-free low absorption coating for infrared CO.sub.2 laser optics comprises an interior BaF.sub.2 layer formed on a substrate and an exterior layer formed over the interior layer to a predetermined thickness sufficient to substantially prevent water adsorption by the interior layer. Generally, the predetermined thickness is greater than about 11000 .ANG., and in one embodiment of a two-layer low absorption coating designed for antireflection at 10.6 microns, the exterior layer has a physical thickness in a range between about 24600 .ANG. and 22800 .ANG., and preferably about 24000 .ANG.. In the preferred two-layer AR coating embodiment, the exterior layer defines a cover layer and an absentee layer, and the interior layer is relatively thin. The preferred exterior layer and the preferred substrate consist essentially of ZnSe. Multilayer stacked coatings of more than two layer can also be formed to provide low absorption partially reflective or totally reflective coatings as well as AR coatings.

Abstract: An infrared lens assembly (16, 60 and 80) operative in the near and far infrared wavebands to focus infrared radiation at an image plane (15) of an infrared detector (18). The infrared lens assembly (16, 60 and 80) includes a focusing component (33, 63 and 83), a collecting component (37, 65 and 85) and a diffracting component (41, 67 and 87). The focusing component (33, 63 and 83) and the collecting component (37, 65 and 85) may be formed from high dispersion, low index material. The diffracting component (41, 67 and 87) may be used to correct color aberrations associated with an infrared waveband.

Abstract: An optical transceiver for transceiving optical signals in an optical LAN includes a first transceiver that detects and transmits the optical signals, a second transceiver that detects and transmits the optical signals, a control coupled to the first and second transceivers, the control transferring information carried by the optical signals between the transceivers, a power storage coupled to the control, and to the transceivers, and a photovoltaic cell coupled to the power storage for replenishing its power.

Abstract: A reimager comprises precisely two positive lenses wherein the chromatic longitudinal aberration lies within the depth of focus and the thermal image position variation likewise lies within the depth of focus over a temperature range of more than .+-.30.degree. (in the embodiment from -40.degree. C. to +70.degree. C.). Aspheric and diffractive surfaces are utilized and, if required, are joined on respective lens surfaces (31, 51, 53, 71, 73).