Abstract: A Z-fold computer paper sheets unfolding/refolding carrier includes a horizontal base, a forward portion of which underlies a computer or printer housing. A supply of folded computer paper sheets is held by a first lower trough between upstanding rod stock open frame members adjacent the carrier base. A second upper trough is connected across the frame members about and forwardly of the first trough so that the second trough will overlie the rear of the computer or printer housing and be positioned to refold printed-on paper sheets exiting from the printer or computer housing. A guide ramps clips on the extends from a front top edge of the upper trough and is pivotable into a position to bridge the gap between the printer paper exit and the upper trough so as to guide the exiting paper to be refolded automatically in the upper trough. All parts other than the ramp are preferably constructed of rod stock.

Abstract: There is disclosed an apparatus for translating the focal points of curved mirrors in a dye laser along a straight line comprising an experimentally selected pivot point for each mirror and a means for causing each mirror to pivot about its pivot point. Rotation of the mirror about the pivot point causes the incoming beam to strike the mirror in a different place on the curved surface such that the angle of reflection changes in such a manner as to compensate for the arcuate movement of the mirror around the pivot point. Also disclosed are hinge designs to allow a mirror to pivot about an apparent pivot point which is much farther away from the mirror than the hinge. Also disclosed are a method for attaching the mirror supports to the laser frame in dye laser construction and a method for tuning the dye laser so constructed for optimum lasing efficiency.

Abstract: There is disclosed a maintenance reminder system for a pump. The system of the invention is coupled to the pump or the control system for the pump and determines the volume of fluid pumped by the pump. In the preferred embodiment, a piston pump is used and piston strokes are counted and converted to total volume of liquid pumped. The computer of the system maintains a database for each maintenance item containing the threshold value for each item and the total volume pumped since the last maintenance. When the total volume exceeds the threshold, a maintenance reminder is displayed and the user may display information from the database as to which item needs service. The computer updates the appropriate fields of the database after the service is performed.

Abstract: A laser amplifier with high gain and high power efficiency comprises a gain medium characterized by at least two optical paths through the gain medium. An optic supplies the input laser pulse along a first optical path, so that the laser pulse has a transverse dimension D.sub.i as it propagates along the first optical path and exits the gain medium as a first pass amplified pulse. A second optic expands the first pass amplified pulse in the transverse dimension to an expanded pulse with transverse dimension D.sub.e, and guides the expanded pulse along a second optical path through the gain medium. The laser pulse exits the gain medium as a second pass amplified pulse. A third optic in a preferred system guides the second pass amplified pulse along a third optical path through the gain medium so that the laser pulse exits the gain medium as the output pulse.

Abstract: Three dimensional objects or models, such as three dimensional images or shapes stored in a computer, are generated as real models by addition of material to a base, such as with photo-hardenable liquid, or by removal of material from an initially oversized mass. Optical feedback is employed to monotor the actual condition of the model being formed, at each work site. The condition of the model at the work site, e.g. the presence or absence of material, is fed back to the machine or building tool, or to a computer controlling the tool. On the basis of such monitoring and feedback, decisions are made whether or not to perform more work at any particular work site. In this way, the actual three dimensional model being constructed is made to conform substantially to stored information relative to the desired dimensions of the model. In a preferred embodiment, models are produced by ablating a mass of small spheres held together by a relatively weak wax or cement.

Abstract: A series resonant power supply is switched at a constant frequency above the audio range, in which a magnetic amplifier is used to control the magnitude of the output voltage. It can be run silently, while providing high power at relatively low cost. The power supply includes a full or half bridge rectifying circuit with first and second common terminals. A magnetic amplifier is coupled from the first common terminal to a second common terminal. The magnetic amplifier includes a first primary coil for conducting current from the first common terminal to the second terminal. A secondary coil for generating an output current, and a control coil receiving a control current are coupled with the first primary coil. A second primary coil is connected to conduct current from the second common terminal to the first common terminal. A second secondary coil and a second control coil are coupled with the second primary coil.

Abstract: A KTP crystal in a nonlinear optical device is heated to and operated at a temperature of at least 50.degree. C. and less than 350.degree. C., and more preferably about 90.degree. C. to about 200.degree. C., and most preferably to about 100.degree. C. to about 125.degree. C., to reduce drift and damage. The KTP crystal is placed in an oven or other heating device, which may be regulated or unregulated. The KTP may be cut at the room temperature phase matching angle and angle tuned for operation at the higher temperature, or the KTP may be cut at the correct angle for phase matching at the operating temperature.

Abstract: An optical wand interface for coupling electrical output signals representative of a bar code scanned by an optical wand to a fixed bar code scanner with no electrical connection for the signals comprises circuitry for amplifying the output signals from the wand and a light emitter for generating light signals representative of the output signals. The amplifier and light emitter are supported within a housing which includes an optical lens for focusing the light signals generated by the light emitter into the optical input window of the fixed bar code scanner when the housing is positioned thereon. In this way, the electrical output signals generated by an optical wand are converted into light signals which are passed directly to and can be processed by the conventional optical receiving portion of a fixed bar code scanner.

Abstract: An improved dye laser having a birefringent tuning filter comprised of one or more birefringent plates wherein each plate is oriented at Brewster's angle to the resonant light beam and is an integer multiple of the thickness of the thickness of the first plate characterized by the fact that the thickness of the first plate is chosen using a new tuning relationship so that a single order tuning curve covers a tuning range of interest. This single tuning curve is almost linear throughout the tuning range and has a tuning angle at the center of the range of approximately five degrees. Also, the tuning curve has a slope throughout the tuning range which provides sensitivity of selected wavelength to tuning angle which is neither too great nor too small. A further refinement in the structure is a non birefringent polarizing plate at Brewster's angle which increases the losses imposed upon light passing therethrough which is polarized at other than Brewster's angle.

Abstract: An optical fiber for use in a pulse compressor which compresses a relatively long width optical pulse to a short width pulse, has a V number between 2 and 2.405 and a .DELTA. of less than 0.3%. In another aspect of the present invention the optimum length of an optical fiber which may be used to generate self phase modulation in a pulse compression apparatus is selected by successively cutting off fixed lengths of the fiber and measuring the optical energy of a pulse from which the Raman band has been separated. When the optical energy no longer increases, the fiber length has been optimized.

Abstract: A tool for use in establishing a precise level line or plumb line or line for alignment uses a visible laser diode for projecting the line. The tool is relatively small and compact, drives the laser diode using batteries contained in the tool, and includes tilt compensation for use on surfaces which are not level, up to about 5.degree. off level, for still delivering a truly plumb or truly horizontal beam. A manual selector device is provided for shifting the beam from a vertical orientation to a horizontal orientation when desired. Specific forms of tilt compensation apparatus are disclosed.

Abstract: A method and apparatus for automatically controlling the depth of earth grading for utilization with a grader or paver is disclosed. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface. A thermistor is provided to automatically compensate for temeprature variations as the grading takes place.

Abstract: A microwave oscillator frequency modulates the output of the laser system to be controlled. The modulated output passes through a molecular gas cell. The output of the molecular gas cell is detected by a square law device, which produces a signal at the desired microwave frequency only when a sideband of the modulated laser output coincides with the desired molecular transition frequency. A quadrature signal pair is produced by mixing the filtered output of the square law device with two phase-shifted signals from the microwave oscillator. The dispersion signal can be used to control the output frequency of the laser system, since its magnitude and sign are uniquely related to the required direction of correction.

Abstract: An adjustable aperture is formed by a plurality of spring members secured over a passage on a frame, each spring member having a first end secured to the frame, a body extending into the passage and a second end opposite the first. The flexible members are mounted so that the plurality of second ends of the spring members form the aperture. A plunger, secured to the frame and contacting the bodies of the spring members, is provided for deflecting the spring members in an adjustable mount along the axis of light going through the passage. By deflecting the spring members which are fixed to the frame, the size of the aperture formed by the second ends of the spring members can be adjusted. The aperture formed is well suited for control of transverse modes in lasers.

Abstract: A high efficiency pumping scheme mode matches the TEMOO laser mode volume with a plurality of spaced apart laser diode pumping sources positioned along a lateral side of a block of laser material. The cavity resonator within the block is configured in a tightly folded zig-zag configuration. Pump radiation from the diode pumping sources is collimated by an optical fiber and is optically coupled to the verticies of the zig-zags. The fold angle less than 20.degree. and preferably less than 10.degree. and is selected to mode match the pump radiation to the mode volume. Parasitic oscillation across the laser block are prevented.In an alternate embodiment the pumping sources are separated from the block of laser material and are optically coupled to the block by the use of a lens. In a second alternate embodiment, the pumping sources are separated from the block of laser material and are optically coupled to the block by means of a plurality of optical fibers.

Abstract: A device for detecting and displaying the relative position of a generally horizontal reference plane of light. even when partial shading of the device occures, includes a photodetector means having including first and second interdigitated photodetector elements positioned adjacent each other on the device. The first and second interdigitated photodetector element provide first and second detection signals, respectively. A circuit means, responsive to the photodetector means, for determines the relative levels of the first and second detection signals such that the position of the reference plane of light with respect to the detector device is determined. A display means, responsive to the circuit means, for provides an indication of the position of the referece plane of light with respect to the detector device.

Abstract: There is disclosed herein a system for testing the flow stability of the pumping system for liquid chromatography. The system determines the flow rate and determines the number of revolutions over which the flow rate is to be measured from the flow rate. The system then measures the value of a signal which is related to the flow rate multiple times for each revolution. The maximum value and the minimum value for each revolution is recorded. After the data from the requisite number of revolutions is collected, a calculation is performed which determines the flow stability indicator which is displayed. The calculation takes a multiple of the difference between the maximum of maximums and the minimum of minimums and divides it by the sum of the maximum of maximums and the minimum of minimums.

Abstract: An electrode for a discharge region of a transversely purged gas discharge laser. The electrode in a discharge region includes blocks of semiconductor material having widely different dielectric constants configured about the center and ground electrodes of the discharge region. When the electrode is subjected to a quickly changing voltage pulse, the different time constants of the blocks of semiconductor material cause a surface discharge to be generated near the surface of the electrode. This surface discharge preionizes the discharge region. Subsequently, as the semiconductor regions become more resistive, the surface discharge dissipates and the electrodes behaves as a resistively ballasted discharge electrode. An electronic circuit for driving the electrode is also disclosed.

Abstract: A laser system for producing pulsed, single longitudinal mode optical energy over a widely tunable range of wavelengths. The system includes an optical cavity and a solid-state gain medium. The optical cavity comprises first, second, and third optical element means. The first optical element means reflects energy received along a reflective optical path and directs the energy toward the second optical element means, which diffracts the optical energy onto a diffraction axis and an output axis. The energy diffracted along the diffraction axis is reflected back toward the second optical element means by a third optical element means, thereby creating a resonant optical cavity. The solid-state gain medium is located on the optical axis between the first and second optical element means and receives optical energy from a pump beam that is within two degrees of being colinear with the reflective optical path.

Abstract: An optimized design for a resonator for a laser housing and assembly is disclosed, comprising a concentrically arranged plasma tube, magnet and resonator tube with the mirrors and associated optics housed at opposing ends of the resonator tube, mounted on rods extending from respective ends of the resonator tube.