Abstract: A laser bar is soldered to a conventional microchannel copper heat sink whose coefficient of thermal expansion (CTE) is locally modified in the area where the laser bar is soldered to better match the CTE of the laser bar. A strip of ceramic material having a CTE lower than that each of the laser bar and of the copper heat sink is soldered to portions of the metallic heat sink located adjacently to the surface area on which the laser bar is located. The inclusion of the ceramic strips enables a laser bar having a nominal CTE of 6.6×10?6/K, to be soldered directly to a copper heat sink having a nominal CTE of 16.5×10?6/K without incurring thermal distortions at the interface that would limit the useful life of the laser bar.

Abstract: A fiber optic clamp assembly for use with an ultra-precision translation stage to precisely align a fiber optical bundle with a laser diode mounted in a sealable enclosure, comprising a housing for receiving the fiber bundle, a flexible seal positionable between said housing and said enclosure; and a pressure collar for urging the seal against the enclosure, said collar being freely movable within the housing so as not to load the translation stage when the housing is being moved by the translation stage to align said bundle with said laser diode and thereafter being movable to compress the flexible seal without disturbing the alignment.

Abstract: A laser diode bar, solder preform and heat sink are assembled prior to reflowing the solder in a manner to prevent molten solder from being drawn by capillary action over the light emitting end of the diode bar. A recessed pin 30 locates the ends of the laser bar and solder preform with respect to an edge of the heat sink so that the laser bar and solder preform overhang the heat sink edge by respective amounts. When molten, the solder will not be drawn by capillary action to obscure the light emitting end of the laser diode bar.

Abstract: Two resonant cantilever beams oscillate in a sinusoidal pattern. Mirrors disposed on the oscillating ends of the cantilever beams are used to multiplex two scanning and collecting light beams. The cantilever beam parameters and mirror configuration are selected so that the scanning light beam is on the first mirror during the linear portion of its scan. As the first cantilever beam oscillates out of the linear portion of the sine wave, the deflection of the first mirror is just great enough to allow the scanning beam to strike the second mirror during the linear portion of the second mirror's scan. The process is repeated twice each cycle. The collection lens is large enough to receive the full aperture of both mirrors at all times. Multiplexing of scanning diodes is also accomplished by a controller circuit which alternately enables diodes disposed on the ends of respective first and second cantilever beams during the linear portion of each sine wave oscillation.

Abstract: An automated retail point of sale scanning system includes a means for preferentially aligning an item traveling on an item path and through a scanning region such that two or more surfaces to be scanned are stably maintained in a substantially coplanar alignment with a corresponding focal plane of a bar code scanner. Two orthogonally disposed belts define an item path. The belts are tilted at an angle from the horizontal so that an item placed on either belt will have at least two surfaces stably registered by gravity, one surface to each adjacent belt. Alternatively, a stationary platen is disposed orthogonally to a transport belt such that at least two surfaces of the item being scanned are stabilized in a focal plane coplanar with a bar code scanner, one surface of the item being stabilized against the platen and another surface being stabilized against the adjacent transport belt.

Abstract: A bar code scanning system which can be operated in two scanning categories: hendheld and fixed. The system incorporates a second scanning element having a fixedly mounted mirror and a dithering mirror disposed in relation to a hand-held scanner which is removably positioned in a holder means.

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 laser structure utilizes air cooling and RF induction excitation of a gaseous active medium. A means for exciting the active medium is provided including a switching power supply utilizing pulse width modulated switching to provide an RF energy output. The RF output is coupled to a tank circuit which comprises a capacitor, an inductor, and at least one coupling structure. A means for generating a magnetic field-along the axial length of the laser bore is provided and can comprise either permanent magnets or a DC source coupled to the coupling structure. The laser further includes means for dissipating heat from the laser bore by utilizing the coupling structures as convective cooling fins with forced air circulated thereabout.

Abstract: A system for displaying information concerning position of a light beam comprises a detector generating a first signal indicating position of the beam along a first dimension, and a second signal indicating position of the beam along a second dimension. A crossed dot bar graph display is coupled to receive the first and second signals. The crossed dot bar graph display includes a first linear array of indicators (LEDs) for indicating position along the first dimension, and a second linear array of indicators for indicating position along the second dimension. The first and second linear arrays intersect at a center indicator. One dot is displayed in the first array showing deviation in the first dimension. One dot is displayed in the second display showing deviation in the second dimension. When both dimensions are aligned to the center indicator, only the center indicator is activated. The system can be expanded to any number of dimensions.

Abstract: A commercial near resonant laser system with a trivalent rate earth ion doped solid state host, such as Nd:YAG, is pumped at an energy sufficient to excite the electrons from the ground level directly to the upper laser level. The laser system is then tuned to a transition from the upper laser level back to the ground level to produce high power output beams. Because the ground level will include a plurality of "Stark split levels", the necessary population inversions can be maintained and laser energy generated. However, the difference between the Stark split level from which the electrons are excited to the upper laser level, and the Stark split level to which the electrons decay in the light producing transition from the upper laser level, is slight. Thus, energy dissipated in heat as electrons decay in non-lasing transitions is minimized.

Abstract: A large number of semiconductor laser sources coupled with tapered fibers provide a high energy density output for the purpose of longitudinal pumping of a solid state gain medium in an unstable resonator. Each semiconductor laser source generates a beam of radiation at the pump wavelength having characteristic lateral and transverse widths. A plurality of light transmitting fibers, each fiber having an input end and an output end, is coupled with the semiconductor laser sources for delivering the light from a remote location to pump the gain medium. The input end of each fiber has a cross-section substantially matching the transverse and lateral widths of the beams generated by the corresponding semiconductor laser source, and is coupled to receive the beam of radiation generated by a corresponding semiconductor laser source. The output ends of the light transmitting fibers are bundled to deliver the beams coupled into the fibers as a composite light source having a high energy density.

Abstract: Alignment of a birefringent tunable laser gain medium characterized by a first face and a second face cut at Brewster's angle so that a plane of polarization is defined. The gain medium is secured in the optical path by a rotatable member having an axis of rotation that is normal to the Brewster faces of the optical device. Coupled with the rotatable member is a support allowing adjustment of the angular position about the axis of rotation fo the rotatable member. An operator adjusts the angular position of the rotatable member until the C-axis of the gain medium lies in the plane of polarization. Even though the C-axis may not be parallel to the direction of polarization, the depolarization effects of the misalignment are eliminated by proper adjustment of the angular position relative to the plane of polarization. A tunable, solid state laser using the alignment apparatus with a birefringent filter achieves greater linear tuning range.

Abstract: A spill control mounting arrangement for a data gathering system which is installed within a checkout counter comprises configuring the data gathering system in two parts, a first part of the system being mounted below an upper surface of the counter and a second part of the system being supported thereon. The footprint of the first part is smaller than the footprint of the second part such that the first part is substantially shielded from spilled liquids by the second part which is constructed to be impervious to such liquids. In particular, the first part may comprise a mounting channel extending across the counter and being substantially narrower in width than the second part, approximately one third the width. Components of the data gathering system are mounted within the channel for mechanical protection as well as protection from spilled liquids. A crowned channel cover can also be provided to prevent a substantial portion of any spilled liquids from entering the channel.

Abstract: In a time chart plotter which uses a liquid ink supply (such as an ink jet plotter) the computer program in the plotter microcontroller is modified so that for any one increment of chart movement, each point in the other dimension (i.e., the signal axis) is plotted only once. This conserves ink and also prevents heavy buildup of ink on the chart.

Abstract: An acousto-optical device includes a solid state substrate having optical characteristics affected by an acoustic wave in the substrate, and a Z-cut lithium tantalate transducer coupled to the substrate for inducing the acoustic wave. Lithium tantalate provides the transducer with a coupling coefficient and acoustic impedance mismatch which generate a very high finesse acoustic standing wave within the substrate. The lithium tantalate also provides low shear wave components with relatively high manufacturing tolerances. The acousto-optical device with a lithium tantalate transducer is also utilized as a high Q modelocker in a laser capable of producing short pulses of laser light.

Abstract: A scanning method and scanning system according to the present invention determines the bar code data printed on a pair of concatenated, two-segment bar code labels, which labels have been scanned by repeatedly sweeping a beam in a succession of scanning passes to determine the left segment data and the right segment data of each of the pair of labels. The labels are of the type in which the left segment data and the right segment data are combinable to form a valid checksum. During scanning, it is noted if a left segment and a right segment were scanned during a single scanning pass across either or both of the pair of labels. Left segment data from a first left segment is combined with right segment data from a first right segment. If a valid first checksum results, the same left data is combined with right segment data from a second right segment. If a valid second checksum results, then left segment data from the second left segment is combined with right segment data from the first right segment.

Abstract: Misalignment of a laser beam due to bending of a plasma tube for an internal resonator ion laser, or another structural element supporting beam guiding optics, is controlled by varying the distribution of heat flow out of the plasma tube or structural element to compensate for any misalignment in response to position of the laser beam. A detector is mounted along the optical path of the laser beam, and generates a position signal indicating drift of the laser beam from a preferred position. A cooling system, thermally connected to the structural material of the plasma tube or the structural element and connected to the detector, conducts heat out of the structural material in a controlled distribution in response to the position signal, so that misalignment of the optics due to thermal bending is minimized.

Abstract: A laser comprising a first mirror having a shape. The shape is generally spherical for typical lasers with the shape of the mirror being defined by the radius of curvature of a reflective surface on the mirror. A second mirror is provided mounted with the first to define a laser cavity. The cross-sectional sizes of the modes of oscillation within the laser cavity are defined by the shape of the first mirror. An aperture at a given location having a fixed cross-sectional size is mounted with the laser cavity. Alternatively, a laser bore which forms an effective aperture at a given location is used. A means is mounted with the first mirror for adjusting the shape of the first mirror so that the cross-sectional size of a selected mode at the given location matches the cross-sectional size of the aperture.

Abstract: A solid state laser including a block of Nd:YVO.sub.2, Nd:YSAG, or Nd:YAB laser material having a cavity-defining mirror at one of its end surfaces is pumped by a laser diode pumping source having narrow bandwidth and is caused to lase in a single longitudinal mode by controlling the relationship between the pump power, the bandwidth of the lasing transition within the laser material, and the absorption depth of the pump radiation within the laser material.

Abstract: A method and apparatus for use with a laser scanner which projects a laser light beam in a scan pattern to facilitate finding a label on a package and reading the symbols thereon. The apparatus comprises a window, positioned adjacent the laser scanner which has an illuminating portion through which the scan pattern is transmitted and a background portion through which the scan pattern is not transmitted. The apparatus also comprises graphic means, adjacent a first part of the background portion of the window, for delineating a target area towards which the package should be directed by an operator to ensure that the label is properly oriented within the scan pattern for the laser light beam to acurately illuminate and read the symbols on the label. The apparatus may also comprise mask means, superposed on a second part of the background portion of the window, for substantially obstructing the laser scanner from the view of the operator.