Abstract: A miniaturized Q-switch is added to the resonant cavity of a compact laser diode pumped solid state laser to produce short high peak power pulses. Q-switching the compact diode pumped solid state lasers takes advantage of the relatively high gain and short cavity length to provide a desirable combination of pulsewidth and pulse energy. Nd:YAG or Nd:YLF are useful solid state laser materials for Q-switching, or other longer lifetime rare earth ions such as erbium or holmium for greater energy storage. The Q-switch is formed of a material such as TeO.sub.2, SF.sub.10, or LiNbO.sub.3 with an acoustooptic figure of merit substantially greater than fused silica. Pulsewidths of 10-50 ns are achieved at pulse energies of 10-20 microjoules. TEMOO output is easily produced by the compact laser pumped solid state resonator. Applications include materials processing, link blowing in semiconductor memories, marking and scribing, and optical time domain reflectometry.

Abstract: A neodymium or other rare earth doped solid state laser is pumped by a matched high efficiency laser diode, including a diode array and a multi-spatial mode extended emitter diode, resulting in a compact, high efficiency and long lifetime laser assembly. The cavity mode volume is matched to a region of absorption in the pumping volume formed by the focused diode beam. Output is in the near infrared range, but can be converted to the visible spectrum by an intra-cavity frequency doubler. A doubling crystal, e.g. KTP, is placed in an optimum location in the laser cavity. Polarization of the beam for frequency doubling may be achieved by using a birefringent material for the rod or by stressing a non-birefringent rod. An amplitude noise suppression etalon may also be placed at an optimum position in the laser cavity. A folded cavity configuration produces a pair of beam waists in the cavity. Pulsed operation can be produced by means of a Q-switch.

Abstract: A method and apparatus for producing preferential polarization of the output light beam from a laser of the kind having a three surface retroreflector comprises mounting the three reflecting surfaces of the retroreflector so that the surfaces are orthogonal in the retroreflector. The preferential polarization is obtained by controlling the combined effects of the orientation of the retroreflector assembly, with respect to the axis of the beam, and the selection of the coatings on the three reflecting surfaces.

Abstract: A pulse compressor compresses a relatively long width optical pulse (of the kind which may be transform limited) to a short width pulse. The compressor includes a color generator which broadens the bandwidth of the long pulse to include any additional colors required for compression to the short pulse. The compressor also includes a grating which has a groove spacing and which is aligned with the output of the color generator at a grazing incidence angle effective for producing a compact grating structure, reduced ellipticity of the beam output from the compressor and high efficiency of light transmission through the device.

Abstract: A power supply circuit for a gas laser has primary circuitry and secondary circuitry supplied by the primary circuitry. A transformer is positioned between the primary circuitry and a secondary circuitry. Within the secondary circuitry is a spark gap and associated circuitry for creating a voltage buildup to achieve a high ionization voltage required for the laser and for releasing the high ionization voltage in pulses for starting the laser. The circuit further includes laser operating supply circuitry associated with the secondary circuitry and the primary circuitry for supplying the laser at a normal operating voltage much lower than the ionization voltage after the laser has started.

Abstract: A compact laser head for a solid state laser has a miniaturized laser rod and output coupling mirror which form a miniaturized laser cavity. A miniaturized frequency doubler crystal placed in the cavity provides frequency doubled output. The laser head is connected by an optical fiber to a separate power supply which contains a laser diode pumping source. A quick disconnect connector enables the fiber optic to be easily connected to the laser head. Pumping radiation is transmitted through the optical fiber to longitudinally end pump the laser rod using fiber coupling imagery. The fiber is aligned with the rod by the connector and the pumping radiation is imaged into the rod by a focussing sphere. The pumping volume is matched to the lasing volume which is determined by the cavity geometry. The quick disconnect laser head allows interchange of different heads with different output characteristics while using a single power supply.

Abstract: A switched resistor regulator controls current flow through a resistor electrically connected to a load by varying the duty cycle of switching the resistor into electrical connection between of a power source and the load to regulate the power to the load. Both current and voltage regulation can be achieved. In a series switched configuration, current flow through a resistor in series with the load is controlled with current flow being maintained by a capacitor is parallel with the load when the resistor is switched off. In a shunt switched configuration current flow through a resistor in parallel with the load is controlled, with a capacitor parallel to the load also being used. In a hybrid configuration a shunt switched resistor is used while the current level to the load is changed by selecting one of several series resistors; a capacitor is also provided parallel to the load.

Abstract: A single unitary structure for an ion laser in which the plasma tube with a surrounding electromagnet is integrated with the laser resonator tube. Cooling channels are formed by a pair of annular channels between the resonator tube, electromagnet and plasma tube. A helical, flow path in the annular channels provides uniform cooling around the resonator tube.

Abstract: A beam scanner system particularly for use with laser scanners employs the back EMF signal from a scanner driving motor for a tachometer signal indicating motor speed. The tachometer signal goes into a phase lock loop for causing the motor at startup to quickly obtain operating speed, and for controlling speed while the motor is in operation. Using the phase lock loop, a clock signal is compared to the tachometer signal from the motor, and power to the motor is increased or decreased whenever and so long as the tachometer signal is not equal to the desired speed. The system therefore provides a very quickly starting scanner, as for use in hand held bar code scanners, without requiring the scanner to be kept energized on standby power when the laser is not active.

Abstract: A gas laser construction includes a second anode in the vicinity of the cathode, so that current can be directed through the second anode when the laser is at low current levels, thereby assuring an adequate supply of electrons around the cathode to avoid flicker in the laser output. Current flow can be controlled between the main anode at the anode end and this second anode, so that the second anode is used only when and to the extent needed. In this way, the power output of the gas laser is more dependably controlled by controlling the current level, even at low current levels, without output flicker which would ordinarily occur.

Abstract: A power control system for controlling the power output of a modulated laser diode receives current pulses of a signal to be evaluated and establishes a DC voltage which represents the peak value of the light pulses out of the laser diode. An integrator feedback loop compares the desired power with the established DC voltage representing the peak value and causes the laser diode to make light pulses at the correct value. The control system includes a sample and hold which is constructed to act in association with the integrator feedback loop to perform at a rate in all substantial respects as if the modulated, chopped light output of the laser diode were continuously on and to produce in a symmetric manner effective control in real time both for an increase and for a decrease in the signal to be evaluated.

Abstract: A laser scanner having a rotating mirror, such as a POS scanner as used in supermarkets, uses a closed-loop velocity controlled DC brushless motor for rotating the mirror. In addition to providing a hall effect motor speed signal which is used for monitoring and safety features in association with the scanner, the DC brushless motor provides the advantages of greatly reduced power consumption, decreased temperature rise, less electrical noise in the analog scanner circuitry, reduced cost, and greatly reduced size, sometimes over 80%. The use of the inherent motor speed signal from the DC brushless motor also enables elimination of costly mechanical windswitches as typically used in prior scanners.

Abstract: A fast axial flow folded laser includes a vessel which houses heat exchangers and a pump which imparts the pumping action throughout the laser. Only one housing is necessary and this housing can also be used as an optical bench for the resonator. In one embodiment a positive displacement rotary pump is utilized and a retroreflector included to mount three fold mirrors. In the folded configuration the retroreflector provides angular stability in any two orthogonal planes parallel to the laser beam.

Abstract: An endbell assembly operatively associated with a laser body includes a metal endbell component sealed to a crystalline endbell component which terminates with a crystalline optical component. The crystalline endbell and crystalline optical component are hermetically sealed without using a frit. This is achieved by polishing and a modified optical contacting technique whereby the optical component and crystalline endbell component are polished to a flatness of about 1/2 wavelength of light, placed in a contacting position and then thermally cycled at a temperature of about 400.degree.-500.degree. C. for about 1 to 10 hours, forming a substantially uniform unitary body. This seal is mechanically strong and minimizes the introduction of contaminants into the endbell assembly. In one embodiment, the crystalline endbell component is metallized and braze-sealed to the metal endbell component. In another embodiment, the two endbell components are hermetically sealed by modified optical contact and thermal cycling.

Abstract: A neodymium or other rare earth doped solid state laser is pumped by a matched high efficiency laser diode, 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 intra-cavity 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 a non-birefringent rod, prior to frequency doubling, or by using a birefringent material such as Nd:YLF for the rod. An amplitude noise suppression elaton may also be placed at an optimum position in the laser cavity; alternatively a ring cavity or pair of quarter wave plates can be used. A folded cavity configuration produces a pair of beam waists in the cavity. Pulsed operation can be produced by means of a Q-switch.

Abstract: An optical scanner apparatus particularly suited for use in a laser bar code reader includes a series of mirrors mounted in a basket-like array about the optical beam axis. A mirror is mounted obliquely across the beam axis, directly on the path of the beam, to fold the beam generally radially outwardly toward the array of mirrors. In one embodiment of the invention the oblique first mirror is rotated about the beam axis, while in another embodiment the oblique first mirror is held stationary and the array of mirrors is rotated, to reflect the beam forwardly, generally in the direction the beam axis is pointing. If the oblique first mirror rotates, a plurality of scan lines, including non-parallel scan lines, are formed on a surface to be scanned; if the array of mirrors is rotated instead of the single mirror, a series of parallel scan lines will be produced. The mirrors can be oriented at desired angles to produce virtually any desired scan pattern.

Abstract: A beam delivery system for delivering a laser beam from a stationary laser to a point in space under robot control has a universal or spherical shoulder joint which is free to rotate in any direction, a wrist joint which receives the beam from the shoulder joint and which allows the beam to be pointed in the required direction and a section of sliding tubes which couple the wrist joint directly to the shoulder joint in a straight line. The beam delivery system is constructed to be readily and effectively associated with a robot. The beam delivery system is mounted with the spherical or universal shoulder joint close to the vertical axis of the robot shoulder and with the spherical shoulder joint below the articulated arm mechanism of the robot so that the beam delivery system accesses a maximum volume beneath the articulated mechanism of the robot. The beam delivery system utilizes a minimum of internal mirrors to minimize power loss in the beam.

Abstract: A hand held bar code reader employs a laser diode as its laser source, for an efficient and compact construction. The diode is modulated, and an associated bar code reading detector is timed accordingly, so that (1) the effects of strong ambient light which may be present on the bar code surface can be subtracted out, by alternating reflected light readings of the detector between laser beam plus ambient and ambient alone, and subtracting the readings electronically, and (2) peak power can be increased to obtain more dependable readings while staying within permissible power levels for such devices, since average power is reduced by the modulation of the laser.

Abstract: A method for checking straightness of an elongated generally cylindrical bore, such as a capillary bore, includes directing a collimated light beam through the bore, with the bore skewed slightly with respect to the beam. This causes a wall of the bore to reflect some of the beam light, forming generally an off-axis ring of reflected light beyond the end of the bore, in addition to an on-axis spot of un-reflected light. Variation in the off-axis reflected light ring pattern by scatter of reflected light indicates non-straightness of the reflecting bore wall. Variation of the light in the ring is determined by measuring equipment. The cylindrical bore may be rotated sequentially through a plurality of positions, such as four positions, to check the entire circumference of the bore. The degree of bore non-straightness may be quantitatively measured electronically or mechanically.

Abstract: A temperature responsive, gas entrapping material contained in a chamber connected to a gas laser tube selectively entraps gas to regulate the pressure in the laser tube. A temperature regulator adjusts the temperature of the gas entrapping material and thereby controls the pressure of the gas in the laser tube. The temperature of the gas entrapping material can be adjusted by cooling or by heating. The pressure in the laser tube is monitored. The tube voltage can be used to monitor the pressure. Temperature adjustment of the gas entrapping material permits development of optimum gas pressure in the laser tube for different wave lengths. In one embodiment the laser is a krypton gas laser and the gas entrapping material is activated charcoal or alumino-silicate. The gas entrapping material may be heated, during assembly of the gas laser, to a temperature high enough to remove foreign material which might otherwise interfere with the operation of the laser tube.