Abstract: In a method of reading a concavo-convex bar code disposed on the surface of an article, the improvement comprising the steps of scanning the concavo-convex bar code by a displacement sensor to detect the concavo-convexity, determining the areas of the resulting concavo-convex waveforms, and comparing the area thus obtained with the reference areas of the thick and thin bars of the bar code to judge the pattern of the bar code.

Abstract: A laser of the flowing gas type employs an optical resonator having mirrors at each end of the lasing region which are supported, without a separate optical bench, by a hollow cylindrical gas-tight housing. Enclosed in the housing are a pump for circulating the gas, electrodes for causing lasing of the flowing gas, and heat exchangers for cooling the gas. Those enclosed structures are subject to thermal expansion and contraction and are hung between a pair of plates. One of those plates is affixed to one end of the housing while the other plate is free to move within the housing so that thermal expansion and contraction of the enclosed structures does not place an appreciable stress on the housing. A heat shield is disposed between the hung structures and the inside wall of the housing to provide a barrier to the transmission of heat to the housing and the housing is liquid cooled to stabilize its temperature. The mirrors of the optical resonator are mounted on rings attached to each end of the housing.

Abstract: A laser angular rate sensor has four corner mirrors forming a substantially square ring laser to reflect two counterpropagating laser beams around a closed path. Dither vibrators are interconnected to two consecutive mirrors in the path to oscillate perpendicularly to their mirror surfaces with 180 degree phase opposition. In one embodiment the mirror displacement is controlled to an amplitude of substantially 0.541 times the wave length of the laser light. In a second embodiment the mirror displacement amplitude is controlled to minimize the alternating component beat amplitude between one of the two laser beams and light scattered by the mirrors from the other beam. A microprocessor responsive to the output beat frequency of the ring laser gyro disconnects the dither drives when the amplitude of the input angular velocity to be measured exceeds a predetermined value greater than the maximum limit of the lock-in range of the gyro.

Abstract: A gas laser of the type in which gas is impelled transversely through a region where lasing of the flowing gas occurs, employs a crossfield blower to propel the gas around a closed loop. The crossfield blower has an elongate impeller that is substantially the same length as the lasing region. The impeller generates at least one vortex in the gas flow. A part of that vortex is situated outside the path of the main gas flow to the lasing region. To remove heat from the gas without appreciably interfering with the main gas flow to the lasing region, cooling means are situated in that part of the vortex that is outside the path of the main gas flow to the lasing region.

Abstract: An improved transverse gas flow RF pumped waveguide laser has been developed utilizing RF discharge waveguide technology in a mid-infrared laser. A potential application has been identified in a continuous wave gas laser. For the laser, the flowing gas provides efficient cooling so that high output power per unit gain length can be achieved.

Abstract: A discharge excitation type short pulse laser device which is constructed with first and second main electrodes disposed in confrontation with the direction of the laser beam axis as their longitudinal direction, an auxiliary electrode provided on the rear surface part of the second main electrode and opposed to the second main electrode through the dielectric member, a pulse circuit for applying a pulse voltage across the first and second main electrodes, and a circuit for applying a voltage across the auxiliary electrode and the second main electrode, the circuit forming a part of the pulse circuit, or being independent of the pulse circuit, wherein the second main electrode is made of an electrically conductive material having a plurality of apertures therein, the second main electrode and the dielectric member are disposed in tight adhesion each other, and the second main electrode is thinly formed to enable creeping discharge to be produced on the surface of the dielectric member, thereby distributing el

Abstract: A buried laser mirror used in high energy applications provides discrimination between optical signals of different wavelengths and comprises a ceramic substrate bonded to a faceplate that has a multicomponent reflective interlayer formed on the faceplate inner surface. The multicomponent reflective interlayer provides improved thermomechanical properties while maintaining the mirror's optical integrity and includes a metal reflective layer formed on the faceplate inner surface, a diffusion barrier layer fabricated on the metal reflective layer and a surface wetting layer formed on the diffusion barrier layer.

Abstract: A current mirror amplifier is provided wherein the feedback path around a diode-connected device is modified by adding a resistor in series with the input terminal of the diode-connected device in order to cancel a pole which appears at the unity-gain frequency. This will improve the frequency response and provide for increased bandwidth. The added resistor may be realized in MOS technology by employing a tracking MOS device.

Abstract: An optical pumping laser system is provided with a resonator suitable for a continuous oscillation having a relatively low gain. The laser system comprises an optical plate such as an etalon plate functioning as a Brewster plate with respect to a pumping beam and also functioning as a reflection mirror with respect to an oscillation laser beam, and a total reflection mirror spaced apart from the optical element so as to define a laser amplification region. The laser system further comprises an output mirror arranged relative to the optical plate to output the oscillation laser beam separated from the pumping beam by the optical element functioning as the reflection mirror. Thus, this laser system provides a uniform pumping of a laser medium having a relatively large cross-section, thus providing improved excitation efficiency and mode quality.

Abstract: A laser diode and a method of making the same, the diode having a semiconductor substrate, and a plurality of strip shaped heterogenous layers sequentially arranged vertically on the substrate, the heterogenous layers between them providing a strip shaped laser active zone. Additional doped semiconductor structures having a lower refractive index than the heterogenous layers are disposed laterally adjacent to the strip shaped heterogenous layers. A zone adjacent to the additional structure exists laterally of the heterogenous layers, this zone having a conductivity type different from that of the additional structures, and having a conductivity of the lowermost of the heterogenous layers, thereby providing a blocking pn junction at the sides of the heterogenous layers at the boundary between the lowermost layer and the additional structures.

Abstract: An interferometer, and corresponding method, for use in the measurement and correction of wavefront aberrations in a beam of radiation. The interferometer includes optical elements for generating a reference beam with a known wavefront phase characteristic. The reference beam is recombined with the sample beam, to produce an interference pattern indicative of the phase aberrations in the sample beam as compared with the reference beam. An array of detectors produces electrical signals corresponding to discrete elements of the detected pattern, and an electrical circuit for each elemental detector generates phase correction signals to be applied to a set of movable mirror elements arranged to effect phase changes in the sample beam path. The movable mirror elements adjust the elemental path lengths of the sample beam to yield zero detected phase differences. The mirror elements may be integrated into the interferometer, or may take the form of a deformable mirror used for phase compensation of a light beam.

Abstract: A photodetector which uses a photoconductive layer for detection is provided with a load resistor which is a layer of the same material and shares the same substrate as the photoconducting layer for temperature compensation. The resistor layer is shielded from the radiation being detected while the photoconductive layer is exposed to the radiation. Advantageously, each layer has the same intrinsic resistance but the resistance layer is a scaled up transformation of the photoconducting layer.

Abstract: During the monitoring of a web (10) especially a sheet of packaging material (foil), (photoelectric) sensors are used for monitoring the material and positioning. These are accommodated in or on a housing (12) which can be handled as an independent unit. Several monitoring systems for sensing different features of the web (10) or of a tear-open strip (25) are provided in the housing on both sides of a slit (13) open on one side.

Abstract: A laser diode has regions laterally flanking a strip-shaped laser junction. In these regions a pn-junction inhibiting the laser current is generated by a re-doping which has been created by dopant diffusion from a given layer through an adjoining, further layer into another layer spaced from the given layer by the further layer.

Abstract: A coating quality measuring device and a pattern plate including one reference pattern portion having a large pattern width and a plurality of strip pattern portions each having a smaller pattern width. The pattern plate is disposed opposite the coated surface. The pattern plate is reflected off the coated surface and a reflected image is formed on an image sensor. The image sensor successively outputs signals each corresponding to the light level of each strip pattern portion on a line extending in a width direction of each strip pattern portion of the reflected image. A computing device calculates an average signal level of the signals outputted by the image sensor, divides the difference between the average signal level and the signal level of each signal by the signal level of the reference pattern portion and calculates a square average value of the obtained division value to obtain a measure of the coating quality of the coated surface.

Abstract: The invention relates to an apparatus for checking containers, e.g. bottles or pots by means of a transport apparatus for transporting the containers along a predetermined path and a lighting apparatus positioned at a side of said path, e.g. at least one flash light means, and a sensing apparatus, e.g. at least one video camera positioned on a corresponding position, said transport apparatus being provided, in the area of said lighting apparatus and said sensing apparatus a part, in which the containers are hung by their collars. The invention proposes to adapt an apparatus of the type mentioned in the preamble in such a way that in said part of said transport apparatus the path is rectilinear, thus avoiding the need of using means to counteract the oblique position necessary in prior art apparatus, in which the path is curved, and avoiding mechanical load due to centrifugal forces.

Abstract: In conventional InGaAsP/InP semiconductor lasers the p-doping in the InP laser level cannot be increased above 1.times.10.sup.18 atoms/cm.sup.3 without adversely affecting the optical characteristics of the devices. However, by introducing a thin low-doped p-InP layer and a thicker highly doped InP layer, good optical characteristics can be maintained and series resistance can be reduced by a factor of 2 to 4, thereby resulting in operable devices having significantly increased operating currents and higher output power than those of the prior art.

Abstract: A gas laser tube has a beryllium inner tube (10) with a precision ground bore aligned on the axis between the anode (20) and the cathode (18) by supporting said inner tube within an alumina outer tube (12) by means of axially spaced, perforated, copper support discs (14). A preferred arrangement has a stainless steel outer jacket forming part of a closed, de-ionized water cooling system.

Abstract: An afocal variable magnification optical system has a first optical system having at least one variable refracting power element; and a second optical system.

Abstract: A feedback amplifier which is constructed as a threshold value switch includes a current fed differential stage and additionally comprises two transistors whose emitters are each connected to one output of the differential stage with a first resistor connected between these two outputs and second and third resistors forming operating resistors connected between the supply voltage and the two transistors, each operating resistor being connected to the collector of one transistor and the base of the other transistor respectively.