Abstract: An iris cap for a beacon is cylindrical in shape with defined wall length to create such an iris for the intended application. One application for example, an axicon will create defined output angle of emission dependent on the source emitter’s output angle and the axicon angle. Given the cost and difficulty of reproducing several MWIR/LWIR beacons for specific applications of maximum positive output angle, the Iris Cap introduces a simple solution. The Iris Cap can create specific maximum angles to reduce risk of over exposure of the beacon, simply by attaching the Iris Cap to the location of the emission with a countersunk screw.

Abstract: A beacon with a preferably anodized aluminum body, cylindrical in shape, and threaded employs a beacon modulation scheme for MWIR/LWIR beacons in which multiple frequencies of emission are overlaid, such as the addition of a high frequency pulse, several orders of magnitude faster than the low frequency blink, the high frequency modulation being beyond the capability of unaided human perception. This modulation would allow a high-speed detector and associated software to lock onto an asset in the presence of background radiation which would otherwise drown out the signal of interest.

Abstract: A beacon with a preferably anodized aluminum body, cylindrical in shape, and threaded. The exact diameter and thread size of a water catcher cap is defined by the accompanying MWIR/LWIR beacon it threads onto. The accompanying component male thread allows the water catching cover to be threaded down completely for when the MWIR/LWIR beacon is powered on, thus creating an IR iris for the beacon emission, also while cooling the MWIR/LWIR beacon by being able to capture water within its open space cavity between the accompanying component and the water catching cover wall. Further in a wet environment, the open nature of the water catching cover permits rapid quenching by ambient water and refill of water catcher. Alternatively, when thread in the upmost position it protects the accompanying MWIR/LWIR beacon point of emission.

Abstract: Cavity lasers exhibit a relatively high beam quality (e.g., M2<1.25) despite a relatively small cavity length (e.g., 50-53 mm) for a high (e.g., ?10 watt) output power device. This enables the construction of physically smaller laser and optical assemblies without sacrificing performance. Reduction of optical photonic interference, which can impair imaging performance, is also facilitated. Laser and optical assemblies may utilize an aperture defined within an optical barrier element to reduce the divergence of the light beam emanating from a diode-pumping laser.

Abstract: A laser-diode structure whose output is largely single-mode utilizes a ridged top layer that defines an amplification region within an underlying emission layer, and which is provided with grooves that suppress the higher modes.

Abstract: A single laser crystal is driven with multiple pumping sources to obtain discrete, collimated outputs without substantial thermal crosstalk, so that the action of one pumping source does not adversely interfere with the action of another source driving the same crystal; that is, an imaging output emanating from one crystal region will neither defeat nor spuriously cause an imaging output in another region.

Abstract: A variable filter arrangement is interposed within the optical path of an apparatus containing a source of imaging radiation directed along an optical path for imaging a recording construction. The variable filter arrangement facilitates selectable reduction in the output energy density of the radiation source without substantially altering the focal length of the optical path. The variable filter arrangement may utilize multiple independent lenses of varying energy density reduction levels or a filter of unitary construction with progressive densities so as to provide a selectable continuum for reduction in the output energy density of the imaging radiation.

Abstract: A laser-diode structure whose output is largely single-mode utilizes a ridged top layer that defines an amplification region within an underlying emission layer, and which is provided with grooves that suppress the higher modes.

Abstract: A linear array of diode laser emitters is manufactured with sufficient thermal and electronic isolation among the emitters to permit separate addressability. The emitter bar has first and second opposed surfaces and a third surface through which the emitters direct output. A first surface of the emitter bar is affixed to a “standoff” element that has conductive surfaces connecting each emitter to a power source; these connections are maintained after a series of spaces is formed between the emitters of the emitter bar. The second surface of the emitter bar is affixed to a heat sink to form a finished assembly.

Abstract: A single laser crystal is driven with multiple pumping sources to obtain discrete, collimated outputs without substantial thermal crosstalk, so that the action of one pumping source does not adversely interfere with the action of another source driving the same crystal; that is, an imaging output emanating from one crystal region will neither defeat nor spuriously cause an imaging output in another region.

Abstract: Individually addressable laser crystals are optically coupled to a single slab of an optical carrier that transmits substantially without distortion. The crystals are separate for thermomechanical isolation but may be closely spaced (generally on the order of 0.003 inch apart), and may originate as a single crystal cut into separate segments.

Abstract: A fixture containing a plurality of parallel optical fibers is aligned using a solder circuit that is itself mounted on the surface. The fixture is positioned on the circuit so as to be in contact with a quantity of solder. With the solder in the molten state, the fixture is aligned with respect to an element receiving light output from the optical fibers, and the alignment is secured by allowing the solder to solidify with the fixture immobilized.

Abstract: Multi-mode laser radiation is focused to a preselected spot size on a recording construction using a controlled-angle diffuser. The diffuser concentrates the radiation, counteracting the dispersive effects of multi-mode output.

Abstract: Optimization of distances between each of an array of imaging devices and the surface of an oppositely disposed rotating drum is accomplished without disturbing the mechanical mounting of the imaging devices. For each device, an optimal distance from the recording construction is established; at this optimal distance, corresponding to substantially proper focus, maximum energy density is delivered to a recording medium on the drum. Rather than alter the actual device-to-drum distance to conform to this optimum, the optical paths between the devices and the drum are changed by varying the spacing between the radiation source (e.g., the end of a fiber-optic cable) and the assembly. This alters the point of focus, and therefore has the same practical effect as moving the device itself. The invention also provides a technique for determining the optimal device-to-drum distance by means of a sequence of imaged regions applied at different device-to-drum distances.

Abstract: Compensation for the effects of duty cycle on the output level of an imaging device, and for the effects of periodically varying distance between the output of the imaging device and its target, is accomplished electronically. An exemplary apparatus includes a source of radiation (generally a laser) having an output level that varies both with an input power level and, undesirably, with the duty cycle. The radiation source is operated to produce, on the recording surface, an imagewise pattern of spots, and an adjustment facility compensates for output-level variations resulting from duty cycle--that is, from the recent pattern of laser activity.