Abstract: A light emitting device includes a light source that emits a primary light having a light energy density exceeding 0.5W/mm2, and a first phosphor that absorbs the primary light to convert the primary light into a first wavelength-converted light having a wavelength longer than that of the primary light. The first phosphor includes a compound serving as a host, the compound being a simple oxide including one kind of metal element or a composite oxide including a plurality of different kinds of the simple oxide as an end member. When an energy conversion value at a peak wavelength of the primary light is E1 electron volts and an energy conversion value at a fluorescence peak wavelength of the first wavelength-converted light is E2 electron volts, a bandgap energy of a crystal of the simple oxide is larger than a sum of the E1 electron volts and the E2 electron volts.

Abstract: A system including an electron beam source for providing an electron beam and at least one undulator system configured to produce free-electron laser (FEL) radiation is described. The undulator system includes undulators and at least one optical section between the undulators. The undulators are configured to induce the electron beam to microbunch and radiate coherently. The optical section(s) are configured to operate on the electron beam and the FEL radiation generated by the electron beam.

Abstract: A dielectric-grating waveguide free-electron laser device generating coherent or laser-like radiation is provided. An electron beam propagates next to a dielectric waveguide with a built-in grating structure to generate highly confined coherent or laser-like radiation in the waveguide through the Bragg resonance, the backward-wave resonance, or the Fabry-Perot resonance provided by the grating-waveguide structure. The dielectric-grating waveguide can be made of linear optical materials or nonlinear optical materials or combination of linear and nonlinear optical materials to enable versatile functionalities, such as laser generation, laser-wavelength conversion, and laser signal processing. Owing to the build-up of the laser modes inside the dielectric waveguide, coherent or laser-like Smith-Purcell radiation is also generated above the grating via coupling and bunching of the electrons with the surface mode fields.

Abstract: The light emitting element according to the present disclosure comprises a first active layer that emits light having a first wavelength by injecting current, a second active layer that emits light having a second wavelength different from the first wavelength by absorbing the light having the first wavelength, and a first reflecting mirror in which a reflectance of light having the first wavelength is higher than a reflectance of light having the second wavelength, wherein the first reflecting mirror is disposed at a position closer to an emission end, from which the light emitted by the first active layer or the second active layer exits outside, than the first active layer and the second active layer.

Abstract: A device is described where an operator uses a handheld nozzle that deposits new material onto a part. The process can be used to create new parts from a substrate, or to repair parts. The device automatically maps the physical part and matches the physical part against a model of the desired part. As the operator moves the nozzle over the part, the device automatically computes the amount of material necessary to modify the current part to match the model of the desired part. This method can be used for spraying or spray-casting metal, ceramics, and other materials. The described process and device automates this process, and simplifies the operator's involvement. Moreover, because the device can measure the part as the material is being deposited, the resulting part is more likely to more closely resemble the original part both in aesthetics and physical properties.

Abstract: A radio frequency (RF) excited laser assembly includes a pair of opposed electrodes defining an inter-electrode gap and a conductive termination bridge in electrical contact with both electrodes. The termination bridge mechanically supports and positions the electrodes relative to each other and provides a termination impedance for an RF voltage applied to the electrodes. A conical spiral inductor includes one or more metals windings, and one or more concentric terminals, such that the conical spiral inductor defines an inter-winding spacing sufficient to mitigate ionization of a gas medium between windings. A radio frequency (RF) feed-through assembly configured to apply an RF voltage to a pair of opposing electrodes such that a conductor is isolated from a metal sleeve position around the conductor by ion sheath discharge barrier.

Abstract: A system for circulating an alkali vapor to operate as, for example, a gain medium in a diode pumped alkali laser. The system includes a pump configured to pump a buffer gas to a metal source. A source heat exchanger heats the alkali metal source to produce a metal vapor that flows with the buffer gas. An action chamber receives the metal vapor and buffer gas combination and contains the combination while the metal vapor performs its required functions. The metal vapor and buffer combination continue to flow to a metal vapor trap and heat exchanger that cools the metal vapor and buffer gas combination. The metal vapor trap collects alkali metal condensate as the combination cools. The diffuser transport channel provides an inflow of clean buffer gas to the pump. The pump provides a circulating gas flow through the closed loop system.

Abstract: A semiconductor light emitting device includes a light guiding structure, a light emitting layer disposed within the light guiding structure, and a structure for discharging excess electric charge within the device. The device may be excited by an electron beam, as opposed to an optical beam, to create electron-hole pairs. The light emitting layer is configured for light generation without requiring a p-n junction, and is therefore not embedded within nor part of a p-n junction. Doping with p-type species is obviated, reducing device loss and permitting operation at a short wavelengths, such as below 300 nm. Various structures, such as a top-side cladding layer, are disclosed for discharging beam-induced charge. A single device may be operated with multiple electron beam pumps, either to enable a relatively thick active layer or to drive multiple separate active layers. Cooperatively curved end facets accommodate for possible off-axis resonance within the active region(s).

Abstract: The invention relates to a method for generating electromagnetic radiation (preferably UV, VUV, XUV, or X-rays), to an optical short-period undulator (10) and to a free-electron laser comprising the latter. To accomplish the method, a high-energy electrically charged particle beam (5) is provided, and high-intensity electromagnetic pulses (7, 7a, 7b) are generated, and by interfering said pulses with one another an electromagnetic standing wave is created, wherein said standing wave has an electric field strength of a pre-determined peak value. The particle beam is directed through the non-steady electromagnetic field of the standing wave in or in the vicinity of a plane spanned by nodes with maximal electric field strength of said electromagnetic standing wave.

Abstract: A method for generating high power electromagnetic radiation based on double-negative metamaterial (DNM), includes providing electrons of an electron beam moving in a vacuum close to an interface between the DNM and the vacuum at a predetermined average speed larger than a phase velocity of an electromagnetic wave propagating in the DNM so as to generate coherent high power radiation. The method can be applied but not limited to high power and compact Terahertz radiation sources and Cherenkov particle detectors and emitters.

Abstract: Embodiments of a method comprising guiding an optical mode with an optical waveguide disposed in silicon, overlapping both the optical waveguide and an active semiconductor material evanescently coupled to the optical waveguide with the optical mode guided through the optical waveguide, electrically pumping the active semiconductor material to inject current directed through the active semiconductor material and through the optical mode, and generating light in the active semiconductor material in response to the injected current. Other embodiments are disclosed and claimed.

Abstract: The present invention is intended to provide an electron-beam-pumped light source capable of irradiating one surface of a semiconductor light-emitting device uniformly with an electron beam, and capable of obtaining a high light output without increasing an accelerating voltage of the electron beam and, in addition, capable of efficiently cooling the semiconductor light-emitting device. An electron-beam-pumped light source of the present invention includes: an electron beam source and a semiconductor light-emitting device excited by an electron beam emitted from the electron beam source, and characterized in that the electron beam source includes a planar electron beam emitting portion and arranged in the periphery of the semiconductor light-emitting device, and light exits from a surface through which the electron beam from the electron beam source of the semiconductor light-emitting device enters.

Abstract: To reduce the laser threshold by efficiently exciting a light-emitting body in a solid-state dye laser with light having high density, thereby facilitating emission of laser beams, and to miniaturize a solid-state dye laser including an excitation light source. A solid-state dye laser capable of emitting laser beams by efficiently introducing light from an excitation light source to a light-emitting body incorporated in an optical resonator structure and exciting the light-emitting body with light with high density, is realized.

Abstract: An undulator comprises a first magnetic circuit (11) for forming a periodic magnetic field, a first support body (21) for supporting the first magnetic circuit (11), a second magnetic circuit (12) arranged opposite to the first magnetic circuit (11), for forming a periodic magnetic field, a second support body (22) for supporting the second magnetic circuit (12), a space (13) formed between the oppositely arranged first magnetic circuit (11) and the second magnetic circuit (12), for passing an electron beam, a vacuum chamber (1) for vacuum-sealing the first magnetic circuit (11) and the second magnetic circuit (12), and a refrigerant passing tube (30) for cooling a permanent magnet (m) constituting the first magnetic circuit (11) and the second magnetic circuit (12) below the room temperature.

Abstract: A device for generating a high-energy particle pulse is provided which comprises a laser system producing laser pulses with pulse length shorter than 100 fs (femtoseconds), and capable to be focused to peak intensities greater than 10A18 W/cmA2, preferred greater than 10A20 W/cmA2 (watts per centimeter squared), a device for shaping the temporal intensity profile accompanying said at least one laser pulse for increasing the laser contrast above 10^5, preferably above IL 0A7, especially 1OA10, and a target capable of releasing a high-energy particle pulse, particularly an electron or a proton pulse, upon irradiation with at least one of said laser pulses. A. corresponding method using the device is also described.

Abstract: An electron radiation apparatus is provided. The electron radiation apparatus includes a beat-wave laser system generating a laser beat wave, an electron emitter emitting a density-modulated electron current induced by the laser beat wave, an electron accelerator accelerating the density-modulated electron current and generating a periodically bunched electron beam, and a radiation device receiving the periodically bunched electron beam and generating an electron radiation with a radiation frequency matched to one of the harmonics of the bunching frequency of the periodically bunched electron beam.

Abstract: Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

Abstract: A device for emission of electromagnetic radiation comprises a source of atomic particles and a collector disposed to receive atomic particles from the source. The collector comprises an emission medium, the medium comprising a crystal having a spatial dimension in the range from about 10 nanometers to about 50 micrometers, wherein the emission medium has the capability to generate opposing charge pairs upon absorption of atomic particles from the source and to emit electromagnetic radiation upon recombination of the pairs. The emission may be via spontaneous emission or, in certain embodiments, by stimulated emission. A laser assembly comprising this device, and methods for making the device are also presented herein.

Abstract: An electron radiation apparatus is provided. The electron radiation apparatus includes a beat-wave laser system generating a laser beat wave, an electron emitter emitting a density-modulated electron current induced by the laser beat wave, an electron accelerator accelerating the density-modulated electron current and generating a periodically bunched electron beam, and a radiation device receiving the periodically bunched electron beam and generating an electron radiation with a radiation frequency matched to one of the harmonics of the bunching frequency of the periodically bunched electron beam.

Abstract: An ultra-compact free electron laser comprising a pair of opposed superconducting cavities that produce identical electron beams moving in opposite directions such that each set of superconducting cavities accelerates one electron beam and decelerates the other electron beam. Such an arrangement, allows the energy used to accelerate one beam to be recovered and used again to accelerate the second beam, thus, each electron beam is decelerated by a different structure than that which accelerated it so that energy exchange rather than recovery is achieved resulting in a more compact and highly efficient apparatus.

Abstract: An electron-beam excitation laser has a laser structure with a light emitter and reflectors on one hand and an electron source on the other hand, wherein at least part of the light emitter or reflectors has a multidimensional photonic crystal structure. An electron-beam excitation laser includes an electron source emitting electrons and a laser structure consisting of a light emitter and reflectors, accelerates electrons from the electron source, and irradiates the electrons to the laser structure to emit a laser beam from the laser structure, wherein the reflectors and/or the light emitter in the laser structure are formed with multidimensional photonic crystals in which dielectrics with different dielectric constants are arrayed in a plurality of directions at periodic intervals, and one of the dielectrics with different dielectric constants may be formed with a light-emitting material.

Abstract: The present disclosure is directed to laser apparatuses for generating coherent electromagnetic laser radiation having an electron beam generator, a diffraction grating element oriented such that a beam of electrons from the electron beam generator is directed over the diffraction grating element, and at least one wing element coupled to the diffraction grating element. In some embodiments, the wing element(s) can be coupled to a top portion of the diffraction grating element. While in others, the wing element(s) can be coupled to a side portion of the diffraction grating element. The present disclosure is also directed to methods of manufacturing diffraction grating elements involving placing at least one secondary conducting sheet having a first height on at least one primary conductive sheet having a different second height, and securing the primary and secondary conductive sheets together. The primary and secondary conductive sheets can be alternating and their thicknesses may also be different.

Abstract: A system and method for implementing a next generation laser-like light source with Free Electron Lasers (FELs) are provided whereby the construction of a Free Electron Laser (FEL) is customized through the use of individual modules having specified characteristics. Such individual modules include conventional lasers, electron guns, linear accelerators, magnetic bunch compressors and permanent magnet, hybrid, and electromagnetic, undulators or a combination of these undulators. These individual modules are arranged to exploit the occurring fundamental and nonlinear harmonics generated in each SP HG FEL to be used themselves as a light source, or alternatively to be a coherent seed for another module, such as, in high-gain harmonic generation (HGHG). An efficient method for producing shorter wavelengths of a synchrotron light source is provided. A three step process including imprinting, upconverting or wavelength shifting and reinforcing or strengthening of the electron beam microbunching is provided.

Abstract: A passively mode-locked optically pumped semiconductor vertical-external-cavity surface-emitting laser (OPS-EXSEL) is disclosed. The laser is mode locked by a semiconductor saturable absorber mirror (SESAM) which forms part of an external cavity. Both the beam-quality limitations of edge-emitting lasers, and the power restrictions of electrically pumped surface-emitting lasers are overcome. The laser uses a semiconductor wafer in which a stack of quantum wells is grown adjacent to a single Bragg-mirror structure. Light from one or more multi-mode high-power diode lasers is focused onto the face of the wafer and pumps the wells by absorption in the barrier regions. The area of the laser mode on the active mirror can be about 104 times larger than the mode area on the facet of an edge-emitting laser, offering scope for the generation of high average power and large pulse energy. At the same time the external cavity enforces fundamental mode operation in a circular, near-diffraction-limited beam.

Abstract: An electron beam pumped semiconductor laser screen and an associated fabrication method are described which provide a display screen that has a relatively long operating lifetime, is less expensive to produce, and operates at lower electron voltages and near room temperature conditions. The laser screen includes a multi quantum well active gain region having quantum wells of GaInP and barrier layers of (AlxGa1−x)Inp, thereby permitting operation in the visible, red spectrum. Moreover, the first layer epitaxially grown on the sacrificial substrate is an etch stop layer of (GaxAl1−x)yIn1−yP that acts as an etch stop during the subsequent etching of the sacrificial substrate and may also be used to adjust the cavity length to the correct resonance condition. The laser screen also includes an output mirror having alternating layers of two different compositions of GaxAl1−xAs that are epitaxially grown on the multi quantum well active gain region.

Abstract: Disclosed are a system, and method, for producing a directly extracted flow of preferred-spin-polarization-direction electrons. The present invention optically pumped electron spin filter system provides a mixture of, typically alkali, atoms and electron polarization direction enhancing buffer gas, to a, preferably, single chamber essentially enclosed space, into which essentially enclosed space is entered a predominately single handedness, preferably laser system produced, beam of photons which optically pumps electrons in atoms to a dark-ground state with a preferred-spin-polarization, that is maintained in the presence of an imposed magnetic field, which magnetic field is oriented essentially co-linear with said beam of predominately single polarized photons.

Abstract: A method and device for providing power to a load are disclosed. A beam of free electrons is directed from a free-electron source, such as an electron gun, into an enclosing conductive surface. The free-electron source includes a cathode, which is maintained at a negative voltage with respect to the enclosing conductive surface. A region around the free-electron source is maintained in a vacuum. The system is configured to switch over a time period between two configurations. In the first configuration, the enclosing conductive surface is isolated from a ground. In the second configuration, the enclosing conductive surface is in electrical communication with the ground. Capacitive energy is discharged from the enclosing conductive surface when in the second configuration with an electrical circuit arrangement and provided to the load.

Abstract: A test circuit operable to examine both differential outputs and single outputs of a device under test (DUT), the circuit comprises a first circuit having as inputs a first output of the DUT and a first set of independent reference voltages, and an output of the first circuit coupled to a plurality of comparators. The test circuit further comprises a second circuit having as inputs a second output of the DUT and a second set of independent reference voltages, and an output of the second circuit coupled to the plurality of comparators. The test circuit further comprises a select circuit coupled to outputs of the comparators, the output of the first circuit and the output of the second circuit. The select circuit outputting the outputs of the first circuit and the second circuit or outputting the outputs of the comparators.

Abstract: Within a vacuum vessel, there are arranged an electron emitting part emitting an electron beam in a first direction, and an optical amplifying part amplifying incident light with the help of energy of the electron beam. The optical amplifying part includes a flat dielectric substrate made of a quartz glass, a rectilinear dielectric optical waveguide provided on the flat dielectric substrate, made of a dielectric material having a high refractive index and extending in said first direction, input and output optical waveguides provided on the dielectric substrate and being coupled with both ends of the dielectric optical waveguide, and a pair of electron beam converging electrodes arranged on respective sides of the dielectric optical waveguide. A velocity of the incident light is delayed during propagation through the dielectric optical waveguide, and a part of the incident light penetrates from the dielectric optical waveguide into the vacuum in the form of evanescent light.

Abstract: Excimers are generated by directing an electron beam at about 5 KeV to about 40 KeV into an excimer forming gas such as He, Ne, Ar, Kr, and Xe or mixtures of these with other gases through a ceramic foil such as SiNx. Vacuum ultraviolet (VUV) light is emitted by the excimers or by other species in contact therewith. The invention can provide intense, continuously operable broadband or monochromatic VUV light sources.

Abstract: A unidirectional optical amplifier comprising an optical dielectric waveguide having a high refraction index for leading light from a light input terminal to a light output terminal and a straight electron beam transit section extended in an electron beam transit direction. The optical amplifier includes an amplifier section for amplifying light in one direction by utilizing an energy level sufficiently higher than a Fermi level, and an emissive section for emitting an electron beam in the electron beam transit section. The electron beam transit section is preferably constituted so that the effective mass of an electron in the amplifier section becomes small, and the optical dielectric waveguide and the electron beam transit section are arranged in such a manner that the wave number of light in the amplifier section becomes large and an electric field component of the light is generated in the electron beam transit direction.

Abstract: A system is disclosed for developing a conditioned electron beam of high quality for an exemplary application to a free-electron source of coherent radiation. The system comprises: a source for producing an electron beam of relatively high energy, a microwave source for generating a microwave field, and a wiggler for generating transverse to the electron beam a periodic magnetic field which cooperates with the microwave field to interact with the electron beam and develop a conditioned electron beam of high quality.

Abstract: This disclosure relates to the production of coherent waves of electromagnetic radiation, especially of short wavelengths including X rays, in the form of pulses or continuous beams, utilizing mutually interacting beams of charged particles that include positive ions and electrons. The atoms of which the ions are formed exist in states of excitation energy by virtue of their ionization. The ions capture electrons as the two beams interact, thereby becoming capable of undergoing de-excitation and emitting characteristic electromagnetic radiation. When heavy elements and a high degree of ionization are involved, the radiation so produced can be of high frequency; often X rays. The radiation energies can be of large natural widths which make conditions favorable for the emissions to be composed into a coherent pulse or beam.

Abstract: Excimers are generated by directing an electron beam at about 5 KeV to about 40 KeV into an excimer forming gas such as He, Ne, Ar, Kr, and Xe or mixtures of these with other gases through a ceramic foil such as SiN.sub.x. Vacuum ultraviolet (VUV) light is emitted by the excimers or by other species in contact therewith. The invention can provide intense, continuously operable broadband or monochromatic VUV light sources.

Abstract: An electron pump organized along the lines of a laser device has an interior chamber with a quartz crystal axially disposed around a metallic rod. The rod and crystal are surrounded by flash lamps, which stimulate the electrons therein to produce an electron flow. A heat exchanger surrounds the interior chamber. An outer chamber surrounding the heat exchanger has wire windings therein to produce an electric field to direct the electron flow. Carbon brushes convert the electron flow into electric current.

Abstract: A master radio-frequency signal output from a master oscillator is input to a frequency converter. The frequency converter generates and outputs a multiplied signal having a frequency higher than that of the master radio-frequency signal by using the master radio-frequency signal. A loss of light reciprocating in an optic resonator of a laser oscillator is controlled by both the master radio-frequency signal output from the master oscillator and the multiplied signal output from the frequency converter. It is possible to highly precisely synchronize a pulse laser beam and a radio-frequency signal.

Abstract: An electron beam pumped semiconductor laser includes a semiconductor laser screen and an electron beam source adjacent the semiconductor laser screen. The semiconductor laser screen comprises a transparent single crystal substrate, an electron beam responsive active gain layer on the substrate, and first and second reflective layers. The epitaxial electron beam responsive active gain layer has a crystal structure in alignment with the crystal structure of the substrate, and the first and second reflective layers define a laser cavity through the epitaxial electron beam responsive active gain layer therebetween. The electron beam source generates an electron beam which impinges on the epitaxial electron beam responsive active gain layer thereby generating a laser output. Accordingly, the single crystal active gain layer can be formed on the substrate by epitaxial deposition techniques increasing the performance and reliability of the electron beam pumped semiconductor laser.

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: 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, including bound surface mode radiation, to generate feedback, resulting in stimulated, coherent emission. Methods are disclosed for increasing the electron beam current above a certain value so as to provide sufficient feedback of the electromagnetic radiation for producing stimulated, coherent emission.

Abstract: A method and apparatus for exchanging energy between relativistic charged particles and laser radiation using inverse diffraction radiation or inverse transition radiation. The beam of laser light is directed onto a particle beam by means of two optical elements which have apertures or foils through which the particle beam passes. The two apertures or foils are spaced by a predetermined distance of separation and the angle of interaction between the laser beam and the particle beam is set at a specific angle. The separation and angle are a function of the wavelength of the laser light and the relativistic energy of the particle beam. In a diffraction embodiment, the interaction between the laser and particle beams is determined by the diffraction effect due to the apertures in the optical elements. In a transition embodiment, the interaction between the laser and particle beams is determined by the transition effect due to pieces of foil placed in the particle beam path.

Abstract: A laser cathode-ray tube having an electron beam source, a means for its control, and a laser target containing a supporting substrate, a cavity resonator formed by two mirrors and multilayer semiconductor structure having active and passive strained layers, whose difference in lattice parameters in a free state is up to 10% or more and which have coherent boundaries between each other in the structure.

Abstract: An electron beam pumped semiconductor laser includes a semiconductor laser screen and an electron beam source adjacent the semiconductor laser screen. The semiconductor laser screen comprises a transparent single crystal substrate, an electron beam responsive active gain layer on the substrate, and first and second reflective layers. The epitaxial electron beam responsive active gain layer has a crystal structure in alignment with the crystal structure of the substrate, and the first and second reflective layers define a laser cavity through the epitaxial electron beam responsive active gain layer therebetween. The electron beam source generates an electron beam which impinges on the epitaxial electron beam responsive active gain layer thereby generating a laser output. Accordingly, the single crystal active gain layer can be formed on the substrate by epitaxial deposition techniques increasing the performance and reliability of the electron beam pumped semiconductor laser.

Abstract: An electron beam and a positron beam accelerated to the same energy are caused to join into a confluence in the same direction by a magnet for joining electrons and positrons, and positronium molecules or beam-shaped para-positroniums of the same phase cooled to transient Bose-Einstein condensation or the vicinity thereof are formed on the axis of confluence by a beam focusing solenoidal coil, thereby simultaneously generating gamma-ray lasers of two wavelengths which accompany annihilation caused by self-stimulated radiation, namely a forward GASER, which is a monochromatic gamma-ray laser having a photon energy of greater than several MeV and a backward GASER, which is a monochromatic gamma-ray laser having a photon energy of less than 200 keV.

Abstract: A method and apparatus is provided for propagating photoelectrons in a semiconductor material and for controlling the direction of photoelectrons produced in a semiconductor material. A selected region of the semiconductor material is irradiated with two beams of light that overlap in space and time. The two interfering light beams have a predetermined phase relationship and are harmonically related such that the frequency of one is approximately a multiple of two of the other. Each of the beams of light produce substantially a same number of photoelectrons in the semiconductor material. As the phase relationship between the two beams is varied, the direction of propagation of the photoelectrons produced, varies.

Abstract: Compact electron gun having a microdot electron source and a semiconductor laser using said gun for electronic pumping. A compact electron gun is provided having a microdot electron emitting source (2), an anode (8) spaced from the microdots, means (16) for applying a high voltage to the and, array (10) of electrodes distributed around the bean emitted by the source for the strip focussing thereof onto the anode. The array also serves as an electrostatic screen for the source with respect to the high voltage of the array. The array is positioned between the source and the anode and has at least two pairs of electrodes (18, 18b, 20a, 20b) of different dimensions which are raised to respectively positive and negative voltages. The positive and the negative voltages produce a weak electrostatic field between the source and the electrode array and a strong electrostatic field between the electrode array and the anode.

Abstract: An optically-pumped or electron-beam-pumped solid-state laser employing as the phosphor material doped nanocrystal particles which as a result of quantum confinement can be caused to exhibit discrete levels in its conduction band that can overlap with the corresponding levels in the doping activator such that resonant energy transfer of excited carriers from the conduction band of the phosphor host to that of the activator will occur. The energy levels in the activator are such as to allow very fast carrier transitions to an intermediate level and a slower radiative transition to a ground state. The result is an energy level structure similar to that of a four-level laser but capable of more efficient conversion of the pumping energy to photon generation.

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: 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: 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.