Abstract: A novel excitation scheme has been developed for discharge lasers. The technique uses an auxiliary circuit based upon pulse transformer technology to induce a fast, high voltage pulse directly onto a ground potential laser electrode resulting in the breakdown of the laser gas mix. Saturation of the pulse transformer core inductance then permits the efficient "switching" of the main energy storage circuit into the discharge.

Abstract: A folded longitudinal flow CO.sub.2 laser with an output of at least several hundred Watts, having a rectilinear tube device of dielectric material containing CO.sub.2, comprising a plurality of individual tubes between end flange devices, disposed serially per fold path. At least one intermediate flange device supports the individual tubes and is aligned with the end flange devices. The intermediate flange device has a gas connecting aperture and a cavity aligned with the individual tubes and the gas connecting aperture, and there is a gas tight sealing device between the intermediate flange device and the individual tubes. A supporting device, which is flexurally-resistant, extends parallel to the longitudinal axis of the laser and has two end zones which are rigidly fixed in the end flange devices in a flexurally-resistant fashion and without clearance.

Abstract: The power output from a laser transmitter is maintained within predetermined levels. These levels are maintained at fixed percentages on either side of the average laser output power which is transmitted, regardless of variations in ambient temperature. This is achieved by coupling the bias current control loop to the modulation current control circuit.

Abstract: A series biasing arrangement for a pair of junction field effect transistors (JFETs), which may be used in RF amplifiers, mixers or oscillators, comprises connecting the JFETs together in series, with the gates of the two JFETs selectively connected to different reference potentials. The first FET is also connected to the DC voltage source. In one embodiment of the invention, two operational amplifiers, whose output leads are connected to the gates of corresponding JFETs have their noninverting input leads connected to selected points on a voltage divider made up of three resistors and their inverting input leads each connected to the source of a corresponding JFET. The drain to source voltage drops across the JFETs are controlled solely by the values of two of the resistors in the three resistor voltage divider. The bias current through the series-connected JFETs can be controlled independently of the drain to source voltage drops across each of the JFETs.

Abstract: A position alignment apparatus aligns a photosensitive substrate and a mask (projection image) at high speed and with high precision. The apparatus has a projection optical system for projecting a pattern image on a mask or reticle onto a photosensitive substrate, a detector for detecting a two-dimensional misalignment of a projected pattern image and a wafer, and means for moving the wafer along orthogonal x- and y-axis directions and for rotating the wafer along a rotational direction within a plane defined by the x- and y-axis directions so as to eliminate the misalignment, wherein the detector has first detecting means with an optical system for detecting at least a misalignment of the wafer along the x-axis direction through the projection lens, and second detecting means with an optical system separate from the projection lens and for detecting at least a misalignment of the wafer along a rotational direction.

Abstract: A multiple pulse electric discharge gas laser system is described in which a plurality of pulsed electric discharge gas lasers are supported in a common housing. Each laser is supplied with excitation pulses from a separate power supply. A controller, which may be a microprocessor, is connected to each power supply for controlling the application of excitation pulses to each laser so that the lasers can be fired simultaneously or in any desired sequence. The output light beams from the individual lasers may be combined or utilized independently, depending upon the desired application. The individual lasers may include multiple pairs of discharge electrodes with a separate power supply connected across each electrode pair so that multiple light output beams can be generated from a single laser tube and combined or utilized separately.

Abstract: A feedforward trunk amplifier having the distortion advantages associated with the feedforward topology while providing significantly reduced power consumption and cost. The trunk amplifier has a discrete preamplifier including active gain and slope control, and a low-power feedforward output stage including a medium-gain, hybrid main amplifier, a high-gain, discrete error amplifier having two gain stages which share the same bias current, and miniature coaxial cable delay lines mounted on the cover of the amplifier housing.

Abstract: A high pressure CO.sub.2 laser waveguide having an extended tuning range. The laser cavity is bounded by a first partially reflecting member and a second partially reflecting member, the second member comprising a reflecting mirror and a diffraction grating member used in the Littrow configuration, the grating being positioned outside the laser cavity and spaced from the second reflecting mirror a predetermined distance. The combination of the mirror and grating provides an effective grating reflectivity which is sufficient to extend the tuning range of the laser to a value not previously available.

Abstract: In the disclosed automatic focus adjusting device of the active type having a light emitting element for projecting light for focus detection onto an object to be photographed, light emitting operation and non-light emitting operations of the light emitting element are periodically effected, and the duty ratio or frequency of the light emitting period is variable.

Abstract: A method of automatically detecting the locations of the frame lines of a reversal film as it is supplied to a processing station, such as a cutting and mounting station, a notching station or the like, so that the frame lines can be used as reference marks for the positioning of the film in the processing station wherein the film is moved past optoelectronic scanner in steps which amount to only a fractional part of the normal width of a frame line. The scanner generates an analog voltage which represents the accumulated light transmission of the film in a scanned area, which extends at right angles to the direction of travel of the film substantially across the picture area of the film and has a width which is only a fractional part of a normal width of a frame line. The extreme value of the voltage obtained during a scanning of at least one normal frame length and corresponding to the lowest light transmission is evaluated as a representation of the light transmission of the scanned film at a frame line.

Abstract: The tuning of the output of a free electron laser to different wavelengths is accomplished using a tilting resonator. In a free electron laser, relativistic electrons travel through a periodic magnetic field and oscillate to amplify coherent optical radiation within a resonator with the same polarization as the magnet. Usually, the electron beam is parallel with the resonator axis and the fundamental harmonic is ordinarily used in the transverse magnetic field. By tilting the resonator axis with respect to the electron beam and transverse magnetic field, the free electron laser's output is tuned to different wavelengths. By using higher harmonics (f=3,5,7, . . . ) the free electron laser produces lasing in several wavelengths simultaneously. These several wavelengths are also tuned by the tilting resonator.

Abstract: Disclosed is a cathode for a ring laser comprising a housing composed of substantially a nickel-iron composition having an inner cavity with a coating of a low sputtering electrically conductive material thereon.

Abstract: A solar tracking device (10) has a shadow plate (12) mounted above support (14). A first pair of photoresponsive sensors (18) is mounted beneath the shadow plate (12). A second pair of photoresponsive sensors (20) is also mounted beneath the shadow plate (12), with a line passing through the second pair of photoresponsive sensors (20) being at an angle to a line passing through the first pair of photoresponsive sensors (18). A fifth photoresponsive sensor (21) is mounted above the shadow plate (12) in a cylindrical enclosure (23). Each of the sensors (18, 20, 21) has a microscopic opening (22) which admits light to the sensors. A "no-hunt" control circuit (100) receives inputs from each of the first and second pairs of sensors (18 and 22) to control operation of positioning motors (134 and 136). Coincidence of inputs from each sensor (18 or 20) and a clocking signal (192) are used to inhibit inputs from each sensor (18 or 20) to motors (134 and 136).

Abstract: A gas discharge device includes a block having one or more gas filled cavities or passageways along which the laser beams may propagate. Coupled to one of these passageways is an exit port which is coupled to a cathode mounted on an outer surface of the block. The exit port is formed so that the cross-section of the exit port decreases with distance from the outer surface of the block.

Abstract: A method for determining the onset of nucleation wherein a zone of a translucent fluid in which crystals may be formed is illuminated by a beam of light. When crystallization commences the crystals in the illuminated zone reflect and scatter light. Some of the scattered light is collected and transmitted to a light sensitive detector operable to generate a signal indicative of nucleation. Upon detection of nucleation either manual or automatic procedures may be instituted to modify the crystallization process in an appropriate manner.

Abstract: The disclosed device responds to pulsed light from a light source to produce electrical signals. A photo-electric transducer element uses a number of signal storage sites on which successive signals from the photo-electric transducer element are accumulated. A signal flow circuit transfers the stored signals from one of the signal storage sites to another in synchronism with the energization and de-energization of the light source. Simultaneously, those signals produced when the light source is energized are accumulated on a common storage site. The other signals produced when the light source is not energized are accumulated on another common storage site. When performing a computation on the basis of an electrical readout of one set of stored signals and another electrical readout of another set of stored signals, the different characteristics of the different storage site prevent inaccurate results.

Abstract: A method is disclosed for optimizing the performance of self sustained diarge rear gas halide lasers by using a gas mixture containing two halogen bearing gases. One of these gases is chosen for its attaching properties to optimize the operation of the discharge. The other gas is chosen for its weak attachment and its ability to form the excimer molecule in collisions with rare gas metastables. A representative strongly attaching halogen donor, XHn, is selected from F.sub.2 and NF.sub.3, and a representative nonattaching halogen donor, YHn, which may be weakly attaching, is selected from CH.sub.3 F, CH.sub.2 F.sub.2, and CHF.sub.3. The XHn gas has a concentration value from approximately 0.1 percent up to about 10 percent which is adjusted to maximize the production rate for excited and positively ionized rare gas atoms to yield the excimer state molecules RgHn*, wherein Rg is a rare gas.

Abstract: A device for sensing the refrigerant level in a receiver tank and thereby detecting the surplus or shortage of the refrigerant in the tank is provided. The sensor device has a photoconductor a part of which is placed in the receiver tank. A light source is disposed at one end of the photoconductor and a light receptor element is disposed at the other end. The quantity of light passed from the light source to the receptor element through the photoconductor is changed as the photoconductor is dipped in the refrigerant in the tank. The surplus or shortage of the refrigerant in the tank is detected from the change in quantity of light received by the receptor element.

Abstract: A camera for visual inspection of defect on an object having a complicated shape is disclosed. This camera is provided with a reflecting mirror having two symmetrical reflecting surfaces to split incident light into two portions and direct them onto two linear image sensing devices mounted on inner surface of the camera body at separate positions. The received lights are converted into electric signals and after processing to obtain a difference signal, a signal indicating presence of a defect is obtained remarkably.

Abstract: The refractive-index value is obtained by radially scanning a near-field image of the fiber output face and by computing, for each image point, the ratio between a first intensity value, obtained in the presence of a mask, having a transmissivity proportional to the fourth power of the transversal beam coordinate and located in a far-field plane, and a second intensity value, obtained in the absence of such a mask. An automated measurement apparatus for implementing the method is also provided.