Abstract: An apparatus and method for enhancing the efficiency of a free electron laser, (10). A plurality of electrodes, (28) are imbedded in an electrically insulating vacuum tube, (18) enclosing the electron beam, (14) and its copropagating electromagnetic wave. A variable computer controlled high voltage d.c. power supply, (29) is connected to the electrodes, (28) for energizing the electrodes, (28) at saturation indicated by detectors, (30) thereby converting d.c. electric potential to electromagnetic radiation without gain degradation.

Abstract: An ion or electron beam is steered or focussed by a circular magnetic field produced by passing a large electrical current through a straight conducting wire, the magnetic field being co-axial with the wire. Annular beams of charged particles coaxial with the straight wire can be focussed onto a circular spot or, depending upon the entry radius of the annular beam and the magnetic field strength, can be induced to follow a looping trajectory. The effect of the steering or focussing system can be enhanced by the provision of a cylindrical conductor which is co-axial with the straight conducting wire and maintained at a voltage sufficient to produce the desired particle trajectory such that the particle beam passes between the wire and the cylindrical conductor. The beam steering or focussing systems is applicable to the fields of beam current density intensification, ion implantation, ion separation and free electron lasers.

Abstract: The apparatus includes a semiconductor laser diode, a mounting for the laser diode and a casing with a window through which light from the diode passes. The casing hermetically seals the diode. A magneto-optical member is provided between the end face of the laser diode and the window. The magneto-optical member has a spontaneous magnetization oriented in the direction of the light transmission and a magnetic field is applied to saturate the magneto-optical member.

Abstract: A TE laser amplifier has a fully closed metal housing. This fact, its geometry, and that of its electrodes (5-7) and/or the reversal of the output polarity make possible a homogenous field distribution, a capability to influence the local amplification process in the laser medium, and a relatively long lifetime of the gas and the laser.

Abstract: An ion or electron beam is steered or focussed by a circular magnetic field produced by passing a large electrical current through a straight conducting wire, the magnetic field being co-axial with the wire. Annular beams of charged particles coaxial with the straight wire can be focussed onto a circular spot or, depending upon the entry radius of the annular beam and the magnetic field strength, can be induced to follow a looping trajectory. The effect of the steering or focussing system can be enhanced by the provision of a cylindrical conductor which is co-axial with the straight conducting wire such that the particle beam passes between the wire and the cylindrical conductor. The beam steering or focussing systems is applicable to the fields of beam current density intensification, ion implantation, ion separation and free electron lasers.

Abstract: A method and means for stabilizing the difference in frequencies between the frequency components of a two frequency laser beam influenced by Zeeman effect frequency splitting, accurately determines the frequency separation independently of the individual frequencies or intensities of either of the frequency components. Frequency stabilization is accomplished by mechanical and thermal adjustments to the lasing chamber length of the laser by a closed loop servo control referencing the frequency difference between laser beam components and a reference signal having a frequency equal to the desired frequency difference.

Abstract: Free-electron lasers and masers are modified by eliminating the resonator cavity as such. The feedback mechanism, essential to oscillation, is distributed through and integrated with the transmission line which guides the electromagnetic wave at the active region where interaction with the electron beam takes place. The feedback structure is created by perturbations in the transmission line along the length thereof at the locations of the zero electric field lines of a desired oscillatory standing wave mode. The perturbations may take the form of axial, helical, and azimuthal deformation of the transmission line.

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: A free electron laser for emitting coherent radiation. The laser includes a wiggler magnet for producing a spatially periodic magnetic field in a drift region into which relativistic electrons are injected in a predetermined direction. An axial magnet is provided which generates an axial magnetic field parallel to the above predetermined direction. The axial field is tapered in field strength within a uniform wiggler region, wherein the wiggler field is of uniform and constant magnitude, such that the tapered field acts to oppose the change in axial electron velocity resulting from the free electron laser interaction as electrons travel through the drift region. The tapered axial field acts to enhance power output and efficiency.

Abstract: An extended laser sensor including a laser with an opticla gain lasing medium optically coupled to an optical resonant cavity including reference and sensor arms. Optical path length variations in the sensor arm induced by an incident physical field modulate the operating parameters of the laser. The field is sensed by monitoring these modulated operating parameters.

Abstract: A highly efficient laser employs a glow discharge electron gun and includes a solid wall cathode that emits a beam of electrons resulting in a plasma that is a negative glow discharge having an electron distribution that has a larger number of high energy electrons than would be present in a Maxwellian distribution of the same electron density.

Abstract: Disclosed is a laser light source device having a laser and an external resonator, wherein as a base, a Faraday rotator is provided at the laser side front of a reflection plane of the resonator so that clockwise and counter-clockwise circular polarizations which have frequencies slightly different to each other are generated, and if a laser such as a semiconductor laser having an eigen-mode having a linear polarization is applied, elements which rotate a polarization by 90 degrees by one emission-and-return through the element, for example, quarter-wave plates, are arranged, The device does not need a strong magnetic field or a strong electric field, and can easily generate lights which are a constant strength. Thus the device can be miniaturized and a high efficiency obtained.

Abstract: A laser discharge tube comprises a discharge envelope and an anode and cathode both disposed within the envelope. The envelope includes a capillary tube having a hole. In this hole the tip portion of the anode is inserted. Outside the envelope there is provided a magnet generating a magnetic field which lies in the vicinity of the anode.

Abstract: Gaseous lasers and their operation wherein during operation in the saturated regime Zeeman reorientation collisions do not occur rapidly compared to the rate at which population is transferred out of their upper lasing level and there exists a static magnetic field of predetermined minimum strength inside the lasing region that is preferably at, or substantially at, the magic angle (approximately 54.70) with respect to the predominate polarization of the laser light in the lasing cavity.

Abstract: The invention provides a novel means of stabilizing a glow discharge device against electrothermal instabilities and electrode induced instabilities comprising imposing a magnetic field on the discharge current to create a sheared flow system within the discharge volume. There is further provided an apparatus for producing a stable high power glow discharge comprising an anode and a cathode adapted to be connected to an electric power source and, when so connected, to establish an electric field and a glow discharge between said anode and cathode and an electromagnet adapted to be connected to an electric power source and, when so connected, to establish a magnetic field across said electric field. This application relates to high power glow discharge devices and to a means of stabilizing such devices against electro-thermal instabilities and electrode induced instabilities.

Abstract: A free electron laser in which the electron beam 12 is sent through the field of a quadrupole magnet 16 which may be untapered or tapered. The beam 12 is sent through the magnet 16 spaced from the symmetry axis of the magnet's poles 22 but on the focusing plane 20 of the quadrupole magnet 16.

Abstract: A harmonic amplifier for a laser beam amplifies a harmonic frequency of the beam. The amplifier generates a series of electric fields across the beam, successive fields being directed oppositely. The spacing between the fields is related to the speed of propagation so as to amplify a particular harmonic. Typically this will be the second harmonic so that the amplifier acts as a frequency doubler. The fields can be provided by an array 6 of electrode pairs positioned on opposite sides of the beam 2 with a voltage generator 8 connected across the sets in alternately opposite sequence.

Abstract: Methods and apparatuses for operating a gas laser which utilize the electrical discharge between the electrodes to increase gas circulation. In a first embodiment, electrical discharges cause a control current (pulse) which activates an electromechanical device disposed within a closed gas flow loop. The electromechanical device acts as a pump and effects gas exchange and heat dissipation with a minimum of elements. In other embodiments, electrical discharges cause pressure fluctuations which increase gas circulation without the use of mechanically moved parts. To this end, connecting lines that determine the direction of the flow are placed between the chambers in order to facilitate equalization of gas pressure. A flow circulation loop is thereby created in a quasi-passive manner when suitably constructed.

Abstract: A low inductance magnetic wiggler for use in electron beam type lasers generates a high intensity spatially periodic magnetic field. The wiggler is formed as a plurality of closed conductive loops having their centers spaced along a common axis. Adjacent loops are connected by a conductor extending parallel to the axis, the connecting conductors being positioned alternately on diametrically opposite sides of the loops.

Abstract: A source of coherent electromagnetic radiation capable of generating or amplifying waves in the centimeter, millimeter, and submillimeter wavelength range. An annular beam of gyrating electrons is produced which is then compressed to its paraxial position by means of a solenoid magnetic field around the wave-guide. This electron beam is also subjected to a transverse motion in an interaction region by a longitudinal rippled (wiggler) magnetic field. Such a field is generated by a periodic assembly of rings magnetized in the axial direction. The electron beam during its accelerated motion generates or amplifies coherent electromagnetic radiation in the centimeter, millimeter, or submillimeter range.

Abstract: In a laser device designed according to the gas transport or convection principle, the division into parts with different functions is replaced by complete integration of the different functions. In the case of an axial flow laser, the laser tube can be designed as a cooled tube and arranged concentrically inside of a circulation turbine.

Abstract: An improved gas laser is disclosed. The laser has a support tube to support and to maintain the alignment of the optical resonator structure. The gas lasing medium is used within the support tube to maintain the tube at a substantially constant temperature above the ambient. Furthermore, an active temperature controller is disclosed. The temperature controller maintains the gas lasing medium in the support tube at a substantially constant temperature. An active pressure controller is also disclosed. The active pressure controller uses a pressure sensor, an electronic processor, and a motor-driven needle valve to maintain the pressure of the gas lasing medium in the laser within the desired operating pressure range. The laser can also be switched in operation from a continuous mode to a pulsing mode. An active power control system is disclosed wherein the power output of the laser, through an active feedback loop is maintained at the desired level.

Abstract: Laser radiation whose wavelength is in the submillimeter wave spectral region is sent through an intercavity dielectric tube positioned inside a coil. The tube contains a gas having large dipole moments and which may be of the same kind as the input beams lasing gas. In response to current therethrough the coil produces an axial magnetic field. The direction of the magnetic field is parallel to the propagation of light transmitted through the dielectric tube. The frequency of the submillimeter wave laser radiation in the tube is shifted from its normal value. The amount of shift is determined by the current in the coil since the resulting magnetic field produces a change in the mean index of refraction of the gas. Thus, the change in index of refraction causes a shift in the laser radiation frequency because the gas within the coil is also located within the submillimeter wave lasing cavity.

Abstract: A Zeeman ring laser gyro is described which includes a laser medium of helium-neon consisting of dual isotopes of Ne.sup.20 and Ne.sup.22 in which 53.5% is Ne.sup.20 and 46.5% is Ne.sup.22 by volume. The laser also includes a reciprocal anisotropic dispersion element of quartz which optically splits right and left circularly polarized laser waves by 250 MHz. The portion of the laser cavity in which laser emission is stimulated is exposed to a colinear magnetic field of 30.sub.-20.sup.+10 gauss. The combined optimum parameters produce a laser gyro insensitive to changes in detuning frequencies and magnetic fields.

Abstract: A preconditioning beam is used to excite gas particles preferentially along a channel between two electrodes in a laser chamber. The preconditioning beam may be an electron beam or a laser beam. An electrical discharge between the electrodes is conducted along the channel by the excited gas particles to form a gas embedded plasma pinch. Depending on the profile of the discharge, the pinch may be stable or collapsing. The pinch emits vacuum ultraviolet radiation which photodissociates molecules of the photolytic laser medium confined by the chamber. The dissociation creates a population inversion, initiating lasing activity. A resonator system reflects the developing laser pulse back and forth through the chamber to stimulate further emissions and facilitate pulse amplification. The developed pulse is transmitted by appropriate means.

Abstract: A method and apparatus are disclosed for optically pumping the atoms of an atomic beam into a single trap state. An atomic beam is produced and is passed through a region of weak magnetic field to produce a magnetic splitting of energy levels. The beam is illuminated with a laser beam to produce selected excitations. The spectral distribution of the laser light is selected (1) to excite the atoms of the atomic beam to excited levels from which the atoms can decay into the trap state and (2) to avoid exciting atoms out of the trap state. Particular applications of the method and apparatus are described for atomic or ionic clocks and masers.

Abstract: An apparatus and method is described for greatly enhancing the power output f a free electron laser. To enhance the electron kinetic energy that is converted to laser radiation, the wave amplification resonance condition is continuously changed along the length of the laser interaction region. The changing resonance condition is achieved by use of a static magnetic field transverse to the injected electron beam, the magnetic field having a longitudinal magnetic field gradient.

Abstract: A method and apparatus for operating a dual-frequency gas laser so as to controllably switch between frequencies makes use of a cavity so tuned that the comb of resonant frequencies is not commensurate with the frequency difference between the laser operating frequencies, and, in a preferred embodiment, with one of the resonant frequencies tuned to coincide with one of the operating frequencies. The cavity length and overall gain at each frequency are so selected that the spacing between resonant frequencies is greater than the breadth above unity gain of the individual peaks of the gain vs. frequency curve. The active material is subjected to a magnetic field which may be varied in a controlled manner. In a preferred embodiment, this field is applied normal to the optical axis of the resonant cavity, and an optical element within the cavity is arranged to act as a plane polarizer with its plane of polarization normal to the magnetic field.

Abstract: The generation of very high power pulses of coherent electromagnetic radiation that are continuously tunable in frequency is accomplished by means of a free electron laser in which a hollow relativistic electron beam is projected along the longitudinal axis of an evacuated drift tube. A first magnetic field expands the electron beam into an annular peripheral interaction region of the drift tube where the beam interacts with a second periodic radial magnetic field. Frequency is varied by changing the electron velocity of the electron beam or by changing the periodicity of the radial magnetic field. The device can be made to operate as an oscillator by the inclusion of resonant cavity defining mirrors within the interaction region, or as an amplifier by injecting a coherent radiation signal into the interaction region. Both oscillator and amplifier functions can be incorporated into a single device.