Abstract: A laser pulse from an ultrashort pulse laser (USPL) is fired into the atmosphere. The USPL pulse is configured to generate a plasma filament at a predefined target in the atmosphere, in which free, or “seed,” electrons are generated by multi-photon or tunneling ionization of the air molecules in the filament. A second pulse is fired into the atmosphere to form a heater beam that impinges on the plasma filament and thermalizes the seed electrons within the plasma filament, leading to the collisional excitation of the electrons in the filament. The excited electrons collisionally excite various electronic and vibrational states of the air molecules in the filament, causing population inversions and lasing, e.g., exciting the C3?u?B3?g(v=0?0) transition of the N2 in the atmosphere to cause lasing at 337 nm.

Abstract: An electron injector including an electron source and a conducting grid situated close to the electron source, one or more RF accelerating/bunching cavities operating at the same fundamental RF frequency; a DC voltage source configured to bias the cathode at a small positive voltage with respect to the grid; a first RF drive configured to apply an RF signal between the cathode and grid at the fundamental and third harmonic RF frequencies; and a second RF drive configured to apply an RF drive signal to the accelerating/bunching cavities. Electrons are emitted by the cathode and travel through the grid to the accelerating/bunching cavities for input into an RF linac.

Abstract: A device for generating terahertz radiation using a phase matched optical rectification technique. The device converts laser radiation to terahertz radiation via a particular type of photonic downconversion. The device includes a crystalline material suitable for photonic downconversion of laser radiation, a first coupling component for coupling the laser radiation to the crystalline material and a second coupling component for coupling the generated terahertz radiation from the crystalline material to the environment. By sustaining the phase matching condition over a significant distance, the device is capable of providing terahertz radiation with high peak and average power.

Abstract: A system and methods for the quasi-remote compression and focusing of a moderate-intensity laser pulse to form a much higher intensity beam that can be directed at a target and used as a probe beam or used in a probe beam converter to generate other forms of electromagnetic radiation or energetic particles. A system for the quasi-remote propagation of high-intensity laser beams in accordance with the present invention comprises a main platform on which a first, “seed” laser pulse is generated, stretched, and amplified, and a remote platform, located at a distance from the main platform, which is configured to receive the amplified and stretched pulse and convert it into the high-intensity laser beam. The high-intensity laser beam in turn can then be converted into one or more probe beams directed at a target object.

Abstract: A system and methods for the quasi-remote compression and focusing of a moderate-intensity laser pulse to form a much higher intensity beam that can be directed at a target and used as a probe beam or used in a probe beam converter to generate other forms of electromagnetic radiation or energetic particles. A system for the quasi-remote propagation of high-intensity laser beams in accordance with the present invention comprises a main platform on which a first, “seed” laser pulse is generated, stretched, and amplified, and a remote platform, located at a distance from the main platform, which is configured to receive the amplified and stretched pulse and convert it into the high-intensity laser beam. The high-intensity laser beam in turn can then be converted into one or more probe beams directed at a target object.

Abstract: A laser pulse from an ultrashort pulse laser (USPL) is fired into the atmosphere. The USPL pulse is configured to generate a plasma filament at a predefined target in the atmosphere, in which free, or “seed,” electrons are generated by multi-photon or tunneling ionization of the air molecules in the filament. A second pulse is fired into the atmosphere to form a heater beam that impinges on the plasma filament and thermalizes the seed electrons within the plasma filament, leading to the collisional excitation of the electrons in the filament. The excited electrons collisionally excite various electronic and vibrational states of the air molecules in the filament, causing population inversions and lasing, e.g., exciting the C3?u?B3?g(v=0?0) transition of the N2 in the atmosphere to cause lasing at 337 nm.

Abstract: An electron injector including an electron source and a conducting grid situated close to the electron source, one or more RF accelerating/bunching cavities operating at the same fundamental RF frequency; a DC voltage source configured to bias the cathode at a small positive voltage with respect to the grid; a first RF drive configured to apply an RF signal between the cathode and grid at the fundamental and third harmonic RF frequencies; and a second RF drive configured to apply an RF drive signal to the accelerating/bunching cavities. Electrons are emitted by the cathode and travel through the grid to the accelerating/bunching cavities for input into an RF linac.

Abstract: An embodiment of the invention includes an apparatus. The apparatus includes a plurality of lasers comprising a plurality of laser paths. The apparatus further includes an incoherent combining beam director in the plurality of laser paths. The apparatus also includes a plurality of optical elements in the plurality of laser paths between the plurality of lasers and the beam director.

Abstract: A device for generating terahertz radiation using a phase matched optical rectification technique. The device converts laser radiation to terahertz radiation via a particular type of photonic downconversion. The device includes a crystalline material suitable for photonic downconversion of laser radiation, a first coupling component for coupling the laser radiation to the crystalline material and a second coupling component for coupling the generated terahertz radiation from the crystalline material to the environment. By sustaining the phase matching condition over a significant distance, the device is capable of providing terahertz radiation with high peak and average power.

Abstract: A method used to detect and identify biological substances suspended in air in the form of aerosols or clouds including generating a remote infrared light beam directed toward the atmospheric contamination, producing an ultraviolet light beam from the infrared light beam by compression via the air through which the IR beam travels, and producing fluorescence of the atmospheric contamination, when the generated ultraviolet light contacts the atmospheric contamination. The fluorescent signals are then processed in order to identify the nature of the atmospheric contamination.

Abstract: A system for detecting atmospheric contamination, the system comprising a laser operable to generate an infrared light beam comprising a longitudinal component and a transverse component the laser remote from the atmospheric contamination, and a processor operable to process a flouresence resulting from contact between the atmospheric contamination and an ultraviolet light being generated from the longitudinal and transverse components of the infrared light of the laser, wherein the processor determines the identity of the fluorescence by comparing the fluorescence to known fluorescence.

Abstract: A method used to detect and identify biological substances suspended in air in the form of aerosols or clouds including generating a remote infrared light beam directed toward the atmospheric contamination, producing an ultraviolet light beam from the infrared light beam by compression via the air through which the IR beam travels, and producing fluorescence of the atmospheric contamination, when the generated ultraviolet light contacts the atmospheric contamination. The fluorescent signals are then processed in order to identify the nature of the atmospheric contamination.

Abstract: A method for generating an acoustic source in a liquid includes transmitting an optical pulse through the liquid so the optical pulse reaches ILIB through pulse compression and ionizes a liquid volume. The pulse compression is achieved through at least one of a) group velocity dispersion induced longitudinal compression of a frequency chirped optical pulse and b) transverse self focusing via a nonlinear optical Kerr effect. The acoustic source can be generated at a controllable remote location many meters from the optical source. The optical source can be a laser or other suitable optical device.

Abstract: The laser synchrotron source (LSS) utilizes a high peak power or high average power laser to generate within a vacuum chamber a laser beam travelling in one direction to interact with an electron beam traveling in an opposite direction in order to generate high-power x-rays. A ring resonator formed by a plurality of mirrors directs the laser beam in a closed loop to impact with the electron beam to produce x-rays. Concave mirrors in the ring resonator focus the laser beam upon the point where the laser beam interacts with the electron beam to intensify the laser energy at that point. When a radio frequency linear accelerator (rf linac) is used to produce the electron beam, x-rays having a short pulse length are generated. When a betatron is used as an electron source, x-rays having a long pulse length are generated.

Abstract: An electron cyclotron maser high-frequency generator/amplifier having a cavity resonator positioned in an axial magnetic field. A spiralling beam of relativistic electrons is injected into the cavity and stimulated emission of radiation by the electrons takes place at the frequency of a wave mode supported by the cavity resonator. The transverse efficiency, defined as the average electron energy loss divided by its initial transverse energy, is maximized by disposing a shaped iron collar about the cavity resonator to provide an axial magnetic field in the cavity resonator whose amplitude increases in the beam direction-of-travel. In an alternative embodiment, the transverse efficiency is maximized by tapering the inner wall of the cavity in the axial direction to provide a wave-mode in the cavity resonator whose electric-field amplitude increases in the beam direction-of-travel.

Abstract: A slow-wave, cyclotron-type, travelling-wave-tube amplifier in which the m-wave interaction is the result of a Weibel-type instability. The travelling wave is slowed down in its propagation through the waveguide by a dielectric liner located on the inner wall of the waveguide. The bunching mechanism is the result of the V.sub..perp. .times.B.sub..perp. Lorentz force.

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.

Abstract: A reflecting electron tube for producing high-power, high-frequency, monoomatic microwave pulses includes an anode which produces little or no ion flux when struck by electrons emitted from a cathode, and requires no applied, external magnetic field. An anode support holding the anode and a cathode shank which supports the cathode are positioned within a vacuum chamber such that the anode is closely spaced from the cathode. The anode support is connected to a pulsed high-voltage supply located external to the chamber. The anode is formed from a material which does not produce a significant amount of ion flux but does permit electrons emitted from the cathode to oscillate through the anode. Electrons oscillating in phase bunch together within the potential well of the system and emit microwave radiation.

Abstract: An electron beam and collective ion-electron beam accelerating apparatus in hich a relativistic electron beam and ions moving with it are accelerated in speed by passing them through a converging waveguide (i.e., a drift tube) of gradually decreasing diameter. The ions are separated from the electrons upon leaving the waveguide.

Abstract: An improved apparatus and technique for providing tunable high power millimeter and submillimeter radiation. A tunable source of microwave energy is coupled to an evacuated drift tube in which an intense relativistic electron beam is propagated while constrained in a magnetic field having a direction parallel to the direction of the electron beam. The microwave energy is directed in a direction opposite to the direction of the electron beam to generate millimeter or submillimeter radiation by backscattering from the intense relativistic electron beam. By tuning the frequency of the microwave energy to be mismatched by a specific amount from the electron cyclotron frequency in the rest frame of the electrons at high beam currents, a coherent scattering of microwave energy from electron bunches will produce enhanced power output of millimeter and submillimeter radiation.