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 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: 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 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: 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: 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: 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: 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: 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 methods for attaching the mirror supports to the laser frame in dye laser construction and for tuning the dye laser so constructed for optimum lasing efficiency.

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.

Abstract: A laser beam three dimensional position measurement system includes a laser transmitter mounted at a stationary reference position at a work site and a receiver mounted on a mobile machine at the site. The transmitter produces a laser reference plane by sweeping a laser beam about the transmitter. The receiver includes a retroreflector which intercepts and reflects laser energy back to the transmitter when the laser beam sweeps past the retroreflector. The system also includes at the transmitter a circuit composed of a photodetector, timer, clock and counter. The photodetector senses laser energy reflected back to the transmitter from the retroreflector. The timer modulates the laser beam produced by the transmitter in response to detection of the beam. The counter is connected to the clock and timer, and is enabled by the timer to start counting electrical pulses received from the clock when the beam is modulated. The counter is disabled to stop counting electrical pulses when the modulation is detected.

Abstract: Fluctuations in input intensity and pulsewidth affect the frequency doubled output pulse of a fiber grating optical pulse compressor in a compressed, continuous-wave, mode-locked Nd:YAG laser system. An optimized intensity servo system greatly reduces these fluctuations and results in as much as 50 dB noise reduction at low frequencies. Fluctuations in either input intensity or pulsewidth are corrected by changing the input intensity by means of the servo system.

Abstract: In a laser apparatus which includes a laser medium exhibiting thermally induced optical distortions, and flash lamp mounted near the laser medium to provide laser pumping radiation, an absorbing filter is mounted between the flash lamp and the laser medium for absorbing radiation in the output spectrum of the lamp which exhibits a low fluorescence efficiency in the laser medium. By absorbing radiation with the low fluorescence efficiency in the laser medium, heat which develops in the laser medium can be limited to control the thermally induced optical distortions.

Abstract: A high effieciency 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 tightly folded zig-zag configuration. Pump radiation from the diode pumping sources is collimated by an optical fiber and the fold angle is selected to mode match the pump radiation to the mode volume. Parasitic oscillation across the laser block are prevented.

Abstract: A scanner includes a microprocessor for controlling operation of the scanner, and an interface circuit, which connects the microprocessor to a host computer and transfers data from the microprocessor to the host computer. Interface apparatus provides an interface between the scanner interface circuit and a personal computer, permitting the personal computer to act as a host. The interface apparatus includes a printed circuit board, output means, mounted on the printed circuit board, for transmitting data from the personal computer to the scanner interface circuit under control of an output strobe signal, and input means, also mounted on the printed circuit board, for transmitting data from the scanner interface circuit to the personal computer under control of an input strobe signal. The interface apparatus further includes an address means, mounted on the printed circuit board, for providing the output and input strobe signals to the output means and the input means, respectively.

Abstract: A spark gap chamber to promote mixing and/or translation of hot residue gases into the surrounding gases in an unpurged spark gap chamber. The shock (and expansion) waves are reflected from walls and other structures within the spark gap chamber to cause the hot residue gases formed by a spark between the electrodes in the spark channel to mix with the unheated gases found elsewhere in the spark gap chamber. The spark gap chamber walls can be symmetric and shaped to cause the reflected shock wave to converge simultaneously on the spark channel or to focus on different portions of the spark channel at different appropriate times. Alternatively, the spark gap chamber walls can be asymmetric with respect to the spark channel and can force the hot residue gases away from the spark channel.

Abstract: A longitudinally pumped laser is characterized by one segment in which the cavity mode is astigmatic. A solid state medium is mounted within the one segment, so that a volume of the astigmatic cavity mode within the laser medium defines a cavity mode volume. A pump beam is supplied collinearly with the cavity mode through a means causing astigmatic focusing of the pump beam in the laser medium to define a pumped volume within the laser medium. The astigmatically focusing means is mounted according to a precalculated parameter that achieves the best possible average match of the pumped volume with the cavity mode volume, in light of the physical limitations on layout of the resonant cavity. The one segment may be defined by a first off-axis spherical mirror and a second off-axis spherical mirror, with a Brewster-cut solid state medium mounted in between.

Abstract: A hollow mirror seat, insertable into the end of a laser tube, has a first portion having a first length and a first outside diameter close to the inside diameter of the laser tube. A second portion of the mirror seat has a second length and a second outside diameter smaller than the inside diameter of the laser tube. A portion of the second length has a region of reduced wall thickness around its entire circumference.

Abstract: A process removes FMOC--OH which is an undesirable by-product of the derivatization of amino acids by FMOC. The process uses a silicone rubber membrane extractor cell. The sample containing the FMOC--OH is held in a silicone rubber tubing, while pentane flows past the outside of the tube; the FMOC--OH is thus extracted from the sample into the pentane. The process is integrated into a conventional high performance liquid chromatography system and is readily automated.