Abstract: A neodymium YAG laser is pumped by a matched laser diode of high efficiency, resulting in a compact, high-efficiency and long-lifetime laser assembly. Output is in the near infrared range, but can be converted to the visible spectrum by an internal frequency doubler. A doubling crystal, which may be a KTP crystal, is placed at an optimum location in the laser cavity. Polarization of the beam may be achieved simply by stressing the YAG rod, prior to frequency doubling.

Abstract: A plasma tube for a gas laser includes a series of heat webs and insulative spacers between the heat webs, with tungsten bore insert members supported by the heat webs and having aligned apertures defining a laser discharge path. To produce the plasma tube, the heat webs, spacers and other connected components are assembled in a vertical stack outside the ceramic tube of the laser, with a stacking gauge which helps assure that the heat webs are correctly spaced apart within close tolerances. The heat webs lie adjacent to annular metallized areas on the inside surface of the ceramic tube when the assembly is inserted into the tube, which is precision-formed ceramic tubing. The tube assembly is heated in vertical orientation to expand the heat webs diametrically so that they engage outwardly against and are brazed to the metallized areas of the ceramic tube.

Abstract: The output of a continuous wave modelocked Nd:YAG laser is first pulse compressed and then frequency doubled from infrared to green, to provide a new pumping source for a synchronously pumped dye laser. The disclosed apparatus and methods can achieve tunable subpicosecond pulses at relatively high average power, over 300 milliwatts. The 1064 nanometer output of the pulse compressor is frequency doubled to 532 nanometers so as to provide 3.5 picosecond pump pulses at 82 MHz and average power exceeding one watt. When this is used to pump a Rhodamine 6G dye laser, tunable pulses as short as 190 femtoseconds output can be obtained from the dye laser, with average power over 300 milliwatts. With the addition of a cavity dumper, tunable subpicosecond pulses of 80 kilowatt peak power have been generated.

Abstract: A capillary bore laser tube is constructed to have little or no power loss when subjected to relatively high shock loads during operation. A spider structure supports the free end of the capillary bore tube in an almost rigid manner against transverse movement of the free end with respect to the outer envelope or jacket of the laser tube so that high shock loads and vibration produce little or no permanent change in the radial alignment of the free end of the bore tube with respect to the other operating components of the laser tube. The spider structure is a disk shaped member which is rigidly attached at its outer periphery to the outer envelope and which is also rigidly attached at its inner periphery to the bore tube. The spider structure is sufficiently flexible in a longitudinal direction to accommodate differential thermal expansion resulting from the differences in temperatures between the bore tube and the outer envelope produced when the laser is energized for operation.

Abstract: An arrangement for use in a laser beam projection device for controlling the orientation of a support frame upon which a laser beam source is mounted includes a base frame, a support frame, and a pivot for mounting the support frame on the base frame. A level arm is pivotally supported at one point by the support frame and carries a level vial which provides an electrical indication of the orientation of the level arm. A positioning arrangement engages the support frame and the level arm and adjusts their relative position. The positioning arrangement includes a threaded shaft having a first threaded portion engaging the support frame and a nut engaging a second threaded portion of the shaft. The nut contacts the level arm. By rotating the nut, the relative position of the level arm and the support frame are adjusted.

Abstract: A sampler for taking samples from multiple sources has a fixed, non-moving needle at a sampling station. A sample vial is lifted from a tray at the sampling station. The needle pierces the septum of the vial and enters the sample as the vial is lifted toward the needle.The sample vial is also rotated as it is lifted, and a bar code reader makes a number of spaced apart, helical reads on a bar code label attached to the vial for label identification of the sample.The needle includes an inner, sample needle and an outer, gas-pressurization needle. The sample is withdrawn by the positive displacement of a syringe connected to the sample needle. The combination of the gas pressurization within the vial and the positive displacement of the syringe insures movement of the sample and accurate control of the volume removed independent of the viscosity of the sample.

Abstract: A wavelength selective mirror provides single wavelength operation of a gas laser. In a specific embodiment an output coupler optical interference coating allows oscillation of the 488.0 nanometer line of the Argon ion laser blue/green spectrum while suppressing all other lines in that spectrum, particularly adjacent lines at 476.5 nanometers and 496.5 nanometers.

Abstract: A floating mirror plate for a laser is suspended in a resonant cavity structure by graphite fiber rods. The cavity structure positions the mirror mounting plates and maintains a highly stable longitudinal spacing of the mirror mounting plates, despite thermal expansion and contraction of other parts of the cavity structure during operation of the laser. The graphite rods are associated with metal tubes and metal bracket support plates for resisting torsion by a construction which does not clamp the metal tubes onto the graphite rods. This construction permits relative movement, in a longitudinal direction, between the metal tubes and the graphite rods to accommodate thermal expansion and contraction of the metal tubes occurring during operation of the laser. The floating plate structure also embodies a rod arrangement in which the rods are not required to be aligned with contact pads for mirror adjusting screws.

Abstract: A mounting system for a laser diode enables adjustment of the location of the diode and of the direction of the diode's beam. Fine adjustments may be made of the location of the diode in side-to-side, up-and-down, and forward-and-back directions as well as rotationally for azimuth and tilt angle. A mounting fork is connected to a frame for movement side-to-side on the frame, with two spaced prongs of the fork extending generally vertically. A diode holder block containing the diode is positioned between the prongs and has cylindrical, generally arcuately convex vertical edges engaged between the generally planar surfaces of the forked prongs. This enables the block to be moved for adjustment by sliding and rotational manipulation up-and-down, forward-and-back, rotationally about a vertical axis for azimuth, and rotationally about a generally transverse horizontal axis for tilt.

Abstract: A system for surveying the contour of land and for automatically determining the most efficient movement of dirt in order to obtain a desired grade utilizes a stationary transmitter which generates a rotating laser beam plane across the field to be surveyed. A receiver and a control circuit are mounted on a vehicle which is adapted to drive across the field. After providing the control circuit with certain initialization data, an operator drives the vehicle over the field in a predetermined manner to enable the control circuit to take elevational readings at selected points. After the survey has been completed, the operator can use the control circuit to display graphical information relating to the surveyed field. The operator can also utilize the control to calculate the amount of dirt which must be moved in order to obtain a desired grade on the field.

Abstract: Methods of and apparatus for identifying peaks corresponding to the same chemical component in a series of liquid chromatograms to identify the peaks without foreknowledge of the chromatographic behavior of any component in the sample, or even the number of components in the sample.

Abstract: A multiple piston assembly pump of the kind which provides an overlap between the flow output of the piston assemblies during a portion of the strokes of the piston assemblies incorporates a method and apparatus for reducing pulsations in the flow during the time when the pump is changing over from one piston pumping to the other piston pumping. A first fast control loop responds to pump output pressure and is operatively associated with a second slow control loop which responds to average pump speed. A sudden pump speed change is detected, and the pump is run in a constant pressure mode until the speed returns to normal.

Abstract: Amplified spontaneous emission is substantially reduced in a novel optical amplifier wherein the gain medium is disposed within a converging region of the coherent signal, which converging region terminates in a waist at or near a limiting stop or saturable absorber. In contrast to the converging coherent signal flux, the amplified spontaneous emission flux is nonconverging and therefore most of the latter is removed by a spatial filter or saturable absorber.

Abstract: A scanning apparatus and method for scanning a beam of light incorporate an optical system in which a rotatable wheel has a plurality of light deflecting facets on the periphery of the wheel. The incoming light beam is reflected by a routing mirror or a routing beam splitter cube onto a front face of a facet as that facet is rotated in line with the routing element. The beam is deflected as it makes its first pass through the facet, and a porro prism redirects the deflected beam back through the rotating facet so that the beam makes two passes through each facet rotating past the routing element. The scanning action is produced by the rotation of the facet in the path of both passes of the beam through the facet. The net result cancels the angular motion of the beam in one direction and adds to the angular motion in the orthogonal direction. Scanning action as produced by one facet is repeated for each facet located on the periphery of the wheel.

Abstract: A four-way valve for selectively controlling the application of fluid and exhaust pressures to opposite sides of a double acting cylinder utilizes a main valve spool that is axially movable in a valve housing defining ports respectively connected to opposite sides of the cylinder and to the pressured and inlet sides of a fluid pressure source. The spool valve is provided with an axial bore and a pilot spool is mounted in such axial bore. Radial passages are provided in the main valve spool connecting its exterior with the axial bore and external sealing portions on the pilot spool cooperate with the radial port so that in a neutral position of both the main valve spool and the pilot spool, no fluid flow occurs.

Abstract: A sampler for taking samples from multiple sources has a fixed, non-moving needle at a sampling station. A sample vial is lifted from a tray at the sampling station. The needle pierces the septum of the vial and enters the sample as the vial is lifted toward the needle. The sample vial is also rotated as it is lifted, and a bar code reader makes a number of spaced apart, helical reads on a bar code label attached to the vial for label identification of the sample. The needle includes an inner, sample needle and an outer, gas-pressurization needle. The sample is withdrawn by the positive displacement of a syringe connected to the sample needle. The combination of the gas pressurization within the vial and the positive displacement of the syringe insures movement of the sample and accurate control of the volume removed independent of the viscosity of the sample.

Abstract: A cold cathode gas discharge apparatus, of the kind in which ionized species are driven against a cathode by an electrical field to eject electrons from the cathode and to produce a discharge within a gas discharge confinement tube, has a cathode constructed for balancing the trapping rate and releasing rate of gas particles in the cathode to maintain a substantially constant gas pressure during the operating life of the gas discharge apparatus. The cathode has an active surface which forms a substantially reentrant cavity about the end of the gas discharge confinement tube.

Abstract: A four-bar alignment adjustment mechanism with elastic hinges enables the mirrors of a gas laser to be very finely tuned with accuracy. A 50.degree. rotation of the fine-adjust knob deflects the mechanism to produce a 1% drop in power from maximum. The system has little backlash and does not use an extra-fine screw to directly move the mirror plate.

Abstract: Autocorrelation traces of laser pulses of short duration are produced by a method and apparatus that uses a rotating glass block to vary the path length on a time scale rapid enough to display the traces on a synchronized oscilloscope. Both paths of a split input beam of a laser pulse pass through the glass block. Rotation of the glass block changes the relative time of travel for light pulses along the two paths. The paths of the two beam arms pass through the block from different directions at a relative angle chosen so that the relative travel time difference is nearly linearly related to the angular position of the block during its rotation.Autocorrelation with rapid scanning through rotation of the block enables measurement of repetitive laser light pulses of very short duration, down to the order of one picosecond.

Abstract: Two concave spherical metal mirrors are used to scan a continuous wave laser beam for heat treating of metals. The mirrors are rotated in opposite directions and each is tilted at a small angle with respect to its axis of rotation. The frequencies of rotation of the mirrors are made constant by a precision timing drive linkage which also allows for phase adjustment. The beam deflection from an individual mirror describes an ellipse, but the deflection when added to that from the second mirror with the proper phase relationship to the first is a straight line. The input laser beam, which is too large in diameter for heat treating, is made to converge by the two mirrors, oriented so as to compensate for astigmatism. Spot size and scan width are adjustable over a wide range, as is scan frequency, which is equal to mirror rotational frequency. The scan produces a uniform, time-averaged distribution of power on the work piece.