Abstract: An apparatus for producing high intensity laser radiation. A vacuum enclosure is provided which includes first and second magnets at each end, and a magnetic field applied along the length of the enclosure. The magnets and applied magnetic field forms a magnetic mirror for electrons of a near relativistic energies introduced into the vacuum enclosure. A thin dielectric material is provides which is charged on each side by some of the electrons which strike the surfaces of the dielectric. The charged dielectric provides high intensity electrostatic fields at the edges thereof. The strength of the magnets and applied magnetic field are selected to produce an oscillation of electrons which pass through the high intensity electrostatic fields and are subject to a radial acceleration which produces free electron lasing. The laser energy is collected by an optical cavity within the enclosure. The laser energy exits an optical port within the enclosure.

Abstract: A linear swept frequency generator includes a signal generator that generates an output signal having a frequency that varies between a first frequency and a second frequency. A delay element, such as an optical fiber having a reflector at one end, is configured to receive the output signal and to produce a delayed version of the output signal. This delayed version of the output signal is provided, along with the output signal, to a mixer that combines the signals to produce a reference signal. Finally, a feedback path between the mixer and the signal generator provides the reference signal to the signal generator so that the signal generator controls the frequency of the output signal in response to the reference signal.

Abstract: A spherical magnet structure having a cavity centrally disposed therein at an axis therethrough, is constructed to distribute a magnetic field in the cavity with the magnitude thereof varying periodically over a circular pattern in a plane passing perpendicular through the axis. Such construction is accomplished with magnet segments of melon wedge configurations which are fabricated and arranged in accordance with the periodic distribution desired for the field. A source of wiggler radiation is derived by combining that magnet structure with means for introducing charged particles into the field which directs the travel thereof around the circular pattern in a periodic path thereacross.

Abstract: A spherical magnet structure having an axis about which an equatorial gap disposed into the periphery thereof, is constructed to sustain a magnetic field across the gap with the field magnitude varying periodically over a circular pattern in a plane passing perpendicularly through the axis. Such construction includes magnet segments which are configured and aligned across the gap in wedge-shaped arrangements to sustain magnetic field contributions thereacross. A source of wiggler radiation is derived by combining the magnet structure with means for introducing charged particles into the gap thereof, wherein the field influences the particles to travel circularly in a continuous periodic path.

Abstract: Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies.

Abstract: A plurality of magnetic poles provided by using magnets are arranged in opposition to one another in pairs. The pairs of magnetic poles are arranged with two kinds of intervals between the adjacent magnetic poles. The two intervals have the relation of an irrational number ratio in accordance with the lining order of generalized Fibonacci series. The series of peak values of the magnetic field or the series of peak values of the double integral values of the magnetic field along the central axis of the magnetic circuit comprising the array of the magnets reside at the positions to satisfy the relation of generalized Fibonacci series.

Abstract: A liquid nitrogen temperature micro-wiggler assembly consists of a stack of micro-wiggler elements. Each micro-wiggler element has a sandwich structure consisting of a non-metallic substrate, a superconducting layer on top of the substrate and a conductive layer on top of the superconducting layer. The undulating magnetic field produced by the micro-wiggler assembly, when supplied with a current, interacts with the electron beam passing through an isolated tube in the center of the micro-wiggler assembly and transverse to it, resulting in the production of optical radiation.

Abstract: A focused optical beam is used to change the path length of the core electrons in electron light sources thereby boosting their efficiency of conversion of electron beam energy to light. Both coherent light in the free electron laser and incoherent light in the synchrotron is boosted by this technique. By changing the path length of the core electrons by the proper amount, the core electrons are caused to stay in phase with the electrons in the outer distribution of the electron beam. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron.

Abstract: An electromagnetic wiggler having a cylindrical member, and a central member disposed axially within the cylindrical member, both of which are formed from alternating cylindrical sections of ferromagnetic and non-ferromagnetic material, each sequential pair of these sections being the length of the wiggler's period .lambda..sub.w. The sequence of sections between the inner and outer members is shifted .lambda..sub.w /2, so that ferromagnetic sections of the outer member are disposed radially opposite non-ferromagnetic sections of the inner member, and vice versa. The resultant radial magnetic flux density in the cylindrical gap between the members is larger and sharper than the flux density for the same wiggler without the central member, permitting higher radiated power output, at higher radiation frequencies, for the same energy of input electron beam.

Abstract: Optical microcavities are potentially useful as light emitters for, e.g., flat panel displays. Such microcavities comprise a layer structure, including two spaced apart reflectors that define the cavity, with a layer of organic (electroluminescent) material disposed between the reflectors. We have discovered that a microcavity can simultaneously emit radiation of two or more predetermined colors such that the emission has a desired apparent color, exemplarily white. Emission of two or more colors requires that the effective optical length of the cavity is selected such that the cavity is a multimode cavity, with the wavelengths of two or more of the standing wave modes that are supported by the cavity lying within the emission region of the electroluminescence spectrum of the active material.

Abstract: A small-sized circular accelerator capable of generating radiation of high brightness, an operation method of the circular accelerator, and a semiconductor irradiation system capable of using radiation of high brightness. An electron beam emitted from a pre-accelerator is injected to the inside of the storage ring by an injector, and accelerated and stored. Thereafter, each of insertion devices respectively disposed in linear orbit sections between main bending magnets and auxiliary bending magnets are excited to generate an alternating field therein. A meandering or spiral movement of the electron beam is caused by this alternating field. By superposing radiations emitted from vertexes of the meandering orbit or the spiral orbit, radiation having high brightness is generated.

Abstract: The free electron laser wiggler has therein a device for generating a variable short period wiggler field. A Type II superconducting material is formed into a field modifying means having a channel therein through which a beam of free electrons travels. The field modifying means is held within a vacuum chamber further having a source of external magnetic fields therein and a cooling means therein. The magnetic field generated must fall within the upper and lower critical magnetic field of the Type II superconducting material. The magnetic field penetrates the superconducting material generating a mixed state of superconducting and normal regions. The amplitude and period of the wiggler field in this structure can be controlled by varying the temperature, applied magnetic field, and the impurity concentration in the superconducting material to affect the fluxoid lattice. The electron beam interacting with this wiggler field outputs short wavelength radiation.

Abstract: Apparatus and method for generating high intensity electrostatic fields for accelerating an electron beam. At least one thin dielectric film is charged on opposite faces thereof with charges of a like polarity. A near-relativistic beam is directed at the charged dielectric film in an area where the electrostatic field created by the surface charges is the greatest. The near relativistic electron beam is radially accelerated by the electrostatic field, generating free electron laser radiation. Electrostatic fields of different polarities or directions are utilized to accelerate the near relativistic electron beam in opposite directions. The radiation generated from each electrostatic field beam interaction is cumulative. Means are provided for charging the dielectric films with the surface charge of the same polarity to generate each electrostatic field.

Abstract: A light-weight permanent magnet structure having a permanent magnet shell that generates a high-intensity internal magnetic field that can be accessed without disrupting the uniformity of that internal field. Particularly, the permanent magnet shell is comprised of permanent magnet material that has a uniform magnetization at each polar angle around the shell, such that its size is minimized in regions where less than the maximum available magnetization of the material is required to maintain the internal field intensity. The resultant structure is a lightweight, low profile, low-cost distortion-free flux source that is easier to construct than the prior art.

Abstract: An undulator providing an increased variable wavelength range of an radiation light. An electron beam, interacting with a microwave as a traveling wave, propagates in a sinuous curve in a waveguide. In the course of propagation, a radiation light is emitted in the direction of propagation of the electron beam. The wavelength .lambda. of the radiation light emitted may be changed greatly by varying the frequency of the microwave.

Abstract: A free-electron laser system and optical polarization conversion are provided for producing azimuthal polarization and radial polarization laser beams. The free-electron laser system includes a helical wiggler for generating a transverse magnetic field around a beam axis. An electron beam is projected along the beam axis and interacts with the transverse magnetic field so as to induce spontaneous and stimulated emission of optical radiation. A resonator cavity is formed by a pair of mirrors in which the optical radiation oscillates therein. The laser system directly produces an azimuthal polarization laser beam as an output. The laser system may further be coupled to an optical polarization converter which includes a pair of optical half-wave plates having a forty-five degree (45.degree.) optical axis difference therebetween. The azimuthal polarization laser beam is transmitted through the optical polarization converter so as to generate a radial polarization output beam.

Abstract: A double beam cyclotron maser comprising two electron guns for introducing two electron beams traveling parallel to each other at different speeds into an electron drift tube/waveguide. The beams have respectively different electron cyclotron space-charge harmonics. A solenoid maintains a magnetic field parallel to the direction of propagation of the electron beams while a magnetic wiggler field initially imparts a transverse force to the electrons such that they propagate down the drift tube with a helical gyration. The magnetic fields, electron beam velocities, and beam space charge harmonics are adjustable to set the interaction frequency at which amplification of electromagnetic radiation can occur. The waveguide is a slow wave structure so configured as to slow the signal from the magnetron to match the phase velocity of the double stream cyclotron space-charge wave.

Abstract: Electrostatic accelerator includes an accelerating column (20), a high voltage terminal (18) located at one end of said accelerating column and electric charge transport means, said transport means incorporating a high frequency accelerator such as a high frequency electron accelerator (54) able to supply an electron beam and means (56) for supplying the electron beam to the high voltage terminal, said electric charges being constituted by the electrons supplied by said high frequency accelerator.

Abstract: A free electron laser with an advanced wiggler. The wiggler is suitable for creating a transverse magnetic field with two periodicities (P1, P2). This thereby results in the emission spectrum being significantly reduced.

Abstract: A magnetic field source that produces a stepped field of greater magnitude than the remanence of the magnetic material used to construct it. The source is basically a magnetic igloo comprised of two hemispheres having different cavity flux value that are separated by a passive ferromagnet slab. The hemispheres are positioned such that they share the same radial center point. The slab has a predetermined thickness and a tunnel of predetermined radius passing through its center along the radial center point of said hemispheres such that the flux in the cavity of the hemisphere abruptly changes when passing from the first hemisphere flux to the second.

Abstract: The object of the invention is a free electron laser with two self-stimulating ondulators at higher order harmonics comprising, in combination, a first section comprising an ondulator (UM1) operating as an oscillator, to generate coherent radiation with a determinate wave length (.lambda.) and simultaneously the higher harmonics relevant thereto, and a second section comprising an ondulator (UM2) operating as an amplifier, tuneable at the frequency and the relevant harmonics of the coherent radiation generated in the first modulator (UM1).

Abstract: A Bragg reflector for selecting a specific spectral line from an output of a free electron laser (FEL) driven in the Raman regime to feed back the spectral line to the FEL. The Bragg reflector comprises at least one reflector pipe (4A), and a plurality of ring-formed plates (8) with their outer peripheries fitted to the inner periphery of the reflector pipe. The plurality of the ring-formed plates are spaced apart from each other at a constant spacing prescribed so that the alignment of the ring-formed plates provide the Bragg reflection of microwaves or far-infrared waves of a prescribed wavelength.

Abstract: An electromagnetic radiation amplification device comprising an electron gun for introducing a stream of electrons into an electron drift tube/wavequide in which an axial magnetic field and a wiggler magnetic field have been induced to impart a helical gyration to the electrons as they travel parallel to the tube. The axial, or guide, magnetic field is directed in the direction opposite to the direction of propagation of the electrons if the electrons have a right handed helical gyration and is directed in the direction of propagation of the electrons if the electrons have a left handed helical gyration.

Abstract: Semiconductor film FEL uses an electron beam and a semiconducting-film-loaded, open, quasi-optical resonator to produce coherent, electromagnetic radiation at submm and far-infrared wavelengths.

Abstract: Free electron laser apparatus, for producing coherent electromagnetic radiation within a spectral range extending from millimeter to visible wavelengths, includes elements for generating an electron beam and for directing the beam to move over the surface of a diffraction grating, thereby producing electromagnetic radiation. Optical or quasi-optical elements confine the electromagnetic radiation to generate feedback, resulting in stimulated, coherent emission.

Abstract: The disclosure relates to an undulator, namely a device generating a transverse magnetic field polarized alternatively North-South and South-North along the path of an electron beam and enabling the direct conversion, in a free electron laser, of a part of the energy of a beam of relativistic electrons into light energy. The undulator comprises a conductor forming, along the path of the electron beam, undulations that wholly or partially induce the transverse magnetic field. To increase the light efficiency, it consists in providing for auxiliary current bypass connectors on said conductor. These auxiliary connectors enable the modulation of the transverse magnetic field as a function of the changing characteristics of the high frequency electrical field which increases during the arrival of a packet of electrons in the optical cavity of the laser owing to the energy yielded by these electrons.

Abstract: The object of the invention is a radio frequency gain follower, in particular for free electron lasers, wherein the equivalent of a variation of the length of the optical cavity is achieved by means of a variation of the time frequency of the packets of electrons that are supplied to the laser by an accelerator machine, in particular a microtron, characterized in that said microtron is driven, through a one or more stage amplifier section, by a frequency generator in turn driven by a function generator.

Abstract: HSFS's or magic spheres are adapted for use in periodic permanent magnet uctures to derive magnetic fields of greater uniformity and average magnitude perpendicularly across an axis along which charged particles are directed in devices, such as radiation sources.

Abstract: A waveguide filter (22,24) is incorporated into a cavity resonator (20) for a free-electron laser or the like by coating a material layer (24) on the inner peripheral surface of a hollow waveguide member (22). A high pass filter configuration is provided when the conductivity of the material layer (24) is higher than that of the waveguide member (22), such that electromagnetic signals having wavelengths longer than the skin depth of the material layer (24) pass into and are affected by the lower conductivity waveguide member (22). Reversing the conductivities produces a low pass filter configuration in which signals having wavelengths shorter than the skin depth are affected by the material layer (24). A bandpass filter configuration is provided by adding an additional material layer (32) of low conductivity to a high pass filter, whereas a band exclusion filter configuration is produced by adding an additional material layer (32) of high conductivity to a low pass filter.

Abstract: In a photon storage ring for storing SR light to generate the same through an outlet port, a reflection mirror is disposed to surround a circular orbit along which bundles of charged particles revolve at a speed close to the velocity of light, generating SR light at a direction tangential to the circular orbit. The reflection mirror has curvature such that the SR light generated in the tangential direction is reflected on the reflection mirror and sent as reflection SR light which is tangential to the orbit. The SR light and the reflection SR light interfere with each other and are guided towards the outlet port.

Abstract: An improved free electron laser is described. The laser comprises an accelerator arranged in order to emit an electron beam along a laser emission line and a circuit loop including a curved line which traces a periodic function along a line parallel with said laser emission line in order to produce a periodic magnetic field along said laser emission line. The periodical circuit is made of a superconducting material, so that the periodical length thereof is made as shown as 100 microns without compromising the strength of the magnetic field induced by the circuit. In another embodiment of the invention, a free electron laser is disclosed where an accelerator is arranged to emit an electron beam along a laser emission line and a plurality of coils are arranged alongside and in substantial parallel with the emission line in order that adjacent coils induce magnetic fields in opposite directions.

Abstract: A compact frequency standard having a dielectrically loaded microwave resonant cavity. One embodiment uses light from a single laser at the frequency that causes F=4.fwdarw.F'=5 transitions in cesium, circularly polarizes a portion of the light to optically pump a cesium beam and uses another linearly polarized portion of the light to detect fluorescence after the beam passes through the microwave cavity. The microwave cavity is preferably dielectrically loaded cavity which is resonant in the TE.sub.011 or TE.sub.013 modes. The dielectric within the microwave cavity is in the form of a hollow cylinder with varying sidewalls displacing the effective axis of the microwave cavity from the geometric axis to produce a Ramsey resonance in a single cavity and creating inhomogeneities in the static field that cause narrow resonance anomalies in the cesium spectrum, which resonances may be locked onto to provide improved frequency standards.

Abstract: A microwiggler assembly produces large magnetic fields for oscillating ched particle beams, particularly electron beams for free electron laser (FEL) application. A tube of electrically conductive material is formed with radial slots axially spaced at the period of the electron beam. The slots have alternate 180.degree. relationships and are formed to a maximum depth of 0.6 to 0.7 times the tube circumference. An optimum slot depth is selected to eliminate magnetic quadrupole fields within the microwiggler as determined from a conventional pulsed wire technique. Suitable slot configurations include single slits, double slits, triple slits, and elliptical slots. An axial electron beam direction is maintained by experimentally placing end slits adjacent entrance and exit portions of the assembly, where the end slit depth is determined by use of the pulsed wire technique outside the tube.

Abstract: The present invention provides in a Free electron laser a means to increase the temporal resolution of the optical pulses while simultaneously increasing the spectral resolution of the pulse train. The increase in temporal resolution is achieved by introducing a quadratic temporal phase variation (i.e. linear frequency chirping) across the pulses, and then propagating the outcoupled pulses through a dispersive relay line to compress them to the transform limit of the broadened spectrum.

Abstract: A laser device disposed around an electron orbit in a SR device, for being excited by SR lights and emitting stimulated emission of radiation. A synchrotron radiation excited laser device comprising a synchrotron radiation device generating synchrotron radiation in the plane including an electron orbit, and a laser medium member formed of a material capable of being excited by synchrotron radiation to a state capable of emitting light, which can form a new light source utilizing SR radiation which has been thrown away in vain in the SR device.

Abstract: A tunable generator or amplifier of intense, collimated, monochromatic electromagnetic radiation includes primarily of a relativistic electron beam, a periodic medium, a periodic magnet or electromagnetic field, a vacuum housing, and, in the primary embodiment, a ring resonator. An accelerator provides a high current, relativistic electron beam which interacts with an electromagnetic wave in a periodic magnetic field and a periodic medium to achieve periodic phase synchronizism between the phase velocity of the electromagnetic wave and the velocity of the said electron beam. The said periodic phase synchronization results in the bunching of the electron beam and the amplification of the electromagnetic wave. In the primary embodiment the growing wave is returned back to the interaction region via Bragg reflectors. The wave continues to grow on each pass through the interaction region formed by the periodic medium and magnetic field.

Abstract: The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Abstract: A free electron laser having an electron source, and an electron accelerator and providing an electrode beam along with a magnetic wiggler traversed by the electron beam and mirrors on each side of the wigglers characterized in such a way that the electron accelerator has a coaxial structure formed by an external conductor and an internal conductor. A high frequency source supplies the cavity of the coaxial structure with an electromagnetic field at the resonant frequency. The radial component of the field has a maximum in at least one plane which is perpendicular to the axis with the external conductor and the internal conductors of the cavity having diametrically opposed openings located in the plane in order to introduce the electron beam into the cavity. An electron deflector deflects the beam which has traversed the cavity along a particular diameter while keeping the beam in the aforementioned plane and then reinjecting the beam back into the cavity along another diameter.

Abstract: Disclosed is a magnetic assembly setting up a helical field of variable amplitude along the axis of the helix, using permanent magnets. The disclosed device is a wiggler with adiabatic insertion for application to free electron lasers and, for this use, it has advantages of simplicity of construction and implementation.

Abstract: Free electron laser.This laser includes a source (2) of electrons, means (4) for accelerating the electrons which supply a beam of electrons, a ring (6) for storing this beam and comprising at least one rectilinear section, magnetic means (22) provided to create a closed magnetic configuration having one first component mainly directed parallel to the circulating beam of electrons and which enables this beam to be contained, and one second component suitable for compensating the drift of the electrons transversally to the axis of the beam of electrons, and at least one magnetic wiggler (10) placed at the level of the rectilinear section and which is traversed by the beam of electrons. Application for fusion controlled by magnetic containment.

Abstract: In a quasi-optical gyrotron, two coils (3a, 3b) in a Helmholtz arrangement generrate a static magnetic field aligned parallel to an electron beam axis (2). As a result, the electrons passing along the electron beam axis (2) parallel to the magnetic field are forced into gyration and excite an alternating electromagnetic field in a quasi-optical resonator. The resonator comprises two mirrors (4a, 4b) arranged opposite to one another on a resonator axis (5). The resonator axis (5) is aligned perpendicularly to the electron beam axis (2) between the two coils (3a, 3b). The mirrors exhibit a mutual distance which is much greater than one half wavelength of the electromagnetic radiation. To generate a wideband radiation, at least one mirror, (4b) is moved at a high frequency by at least about one half wavelength of the electromagnetic radiation by a vibrator (10).

Abstract: An improved free electron laser is described. The laser comprises an accelerator arranged in order to emit an electron beam along a laser emission line and a circuit loop including a curved line which traces a periodic function along a line parallel with said laser emission line in order to produce a periodic magnetic field along said laser emission line. The periodical circuit is made of a superconducting material, so that the periodical length thereof is made as shown as 100 microns without compromising the strength of the magnetic field induced by the circuit. In another embodiment of the invention, a free electron laser is disclosed where an accelerator is arranged to emit an electron beam along a laser emission line and a plurality of coils are arranged alongside and in substantial parallel with the emission line in order that adjacent coils induce magnetic fields in opposite directions.

Abstract: Apparatus, and a related method for its operation, for producing a high-power optical beam from a free-electron laser, at a high overall efficiency. Electrons are accelerated in an electron acceleration system producing bunches of electrons having a narrow energy spread but relatively long time spread. A bunch compression technique converts each bunch to one having a narrow time spread and relatively wide energy spread, suitable for injection into the gain region of a free-electron laser. After exit from the gain region, each electron bunch is further processed to restore it to the same energy-phase distribution as electrons produced by the acceleration system. The restored bunches of electrons are decelerated in the acceleration system, to conserve energy and increase the overall efficiency of the system.

Abstract: A method is disclosed of employing free electron lasing action at a first frequency to achieve gain in output power at a second frequency. In a broadest sense, an electron beam is driven with an electromagnetic wave at said first frequency in a first stage, having a first spatial period, to cause bunching of the electron beam. The electrons in the beam are oscillated with a second stage, having a second spatial period, to generate electromagnetic wave power from said beam at the second frequency.In a specific embodiment, the second frequency is near a harmonic of said first frequency. And in a particular implementation, the first stage is provided by a free electron laser having a first wiggler with a first spatial period, the second stage is a second wiggler having a second spatial period and a drift region is disposed between the first and second stages.

Abstract: Free electrons laser with gaseous medium wiggler and method to use this laser. The laser includes a chamber (22) designed to be traversed by a beam of previously accelerated electrons, a wiggler (44) which creates in this chamber a periodic magnetic field interacting with the beam of electrons, and means (54) to fill the chamber with a gas formed of atoms or molecules having at least one resonance line at a determined frequency. The laser is tuned on this resonance line, which enables the laser to produce a frequency light close to this determined frequency.

Abstract: In a free-electron laser oscillator, two laser beams having different wavelengths are irradiated to a photoemitter to generate an electron beam. The electron beam is density-modulated by a frequency corresponding to a difference between frequencies of the two laser beams, and accelerated to a vicinity of light velocity by a microwave. Such a relative theory electron beam is directed into a periodical magnetic field generated by a helical wigglar and a track thereof is deflected. As a result, a synchrotron radiation light is generated from the relative theory electron beam. The radiation light generates an electromagnetic field by itself. Thus, electromagnetic interaction takes place among the electromagnetic field, the periodical magnetic field and the relative theory electron beam, and the laser oscillation is started.

Abstract: Deviations between the actual electromagnetic field induced by a wiggler and a desired induced field are computed. Then the effect of adding shims at each position within the wiggler are determined and thicknesses of appropriate shims calculated to reduce the overall error of the resulting induced magnetic field from the desired magnetic field.

Abstract: The performance of free electron lasers can be greatly enhanced by including a non-linear optical element within the resonator for the oscillator. A system is described to enhance the peak or average power output of the FEL oscillator, or to modify the time structure of the oscillator output through the use of a non-linear element which modulates or diverts a portion of the optical wave circulating in the resonator.

Abstract: Apparatus and method are provided for causing different groups of particles from an accelerated electron or positron beam to interact exclusively in different sections of a free electron laser. The sections may be one or several amplifiers and an oscillator. The electron beam of a single accelerator used to excite a free electron laser is directed to traverse first an amplifier section or a sequence of amplifier sections and thereafter is directed into an oscillator section where the electron beam induces lasing. If the beam source is pulsed, this invention produces the proper time synchronization of electron and laser pulses. Specifically, delay times between optical pulses are employed among the oscillator and the amplifier or amplifiers to cause the laser to oscillate on the appropriate subharmonic or subharmonics of the accelerator repetition rate so that the intervening electron pulses are used only in the amplifier or amplifiers.

Abstract: A permanent magnet design including a Chiron Wiggler, which is able to produce a magnetic field to accelerate and focus electrons in a high frequency laser without the use of an externally powered, current driven solenoid.