Abstract: A system and method for obtaining improved performance of chemical laser systems by exercising control over the radiation environments of these devices. Proper control of the AERE is achieved through the control of the wall construction including the choice of materials, placement and contours, the control of the wall temperatures (separately from the gas phase temperature), and the use of optical filters or added radiation sources, to achieve a synergistic optimum performance that demonstrates superior performance characteristics beyond that which could be achieved without the control of the AERE. This control is exercised through the proper application of anti-reflecting coatings for those spectral ranges that need to be mitigated and reflecting coatings for those frequencies that need to be augmented. The determination of these frequencies is made through the application of a novel mathematical model to the kinetic processes of the laser system.

Abstract: The generation of ultrabright, multikilovolt coherent tunable x-radiation resulting from amplification on hollow atom transition arrays is described. Amplification has been demonstrated by physical evidence including (a) the observation of selected spectral components of several Xeq+ hollow atom transition arrays (q=30, 31, 32, 34, 35, 36, 37) radiated axially from confined plasma channels, (b) the measurement of line narrowing that is spectrally correlated with the amplified transitions, (c) evidence for spectral hole-burning in the spontaneous emission, a manifestation of saturated amplification, that corresponds spectrally with the amplified lines, and (d) the detection of an intense narrow (??x˜0.2 mr) directed beam of radiation in the far field of the source.

Abstract: An organic laser cavity device, that includes: a first dielectric stack for receiving and transmitting pumped beam light and being reflective to laser light over a predetermined range of wavelengths and having a substantially low threshold for optical excitation; an organic active region for receiving the transmitted pumped beam light and laser light from the first dielectric stack, and emits the laser light; a second dielectric stack for reflecting the transmitted pumped beam light and the laser light from the organic active region back into the organic active region, wherein a combination of the first and second dielectric stacks and the organic active region outputs the laser light; and an external self-contained photon source of the pumped beam light cooperating with the organic laser cavity for optical excitation at the substantially low threshold.

Abstract: An apparatus and method for modulating a phase of optical beam with reduced contact loss. In one embodiment, an apparatus according to embodiments of the present invention includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus further includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type, which is opposite to the first conductivity type. A first contact is coupled to the optical waveguide at a first location, which is outside an optical path of an optical beam that is to be directed through the optical waveguide. A first buffer of insulating material is disposed along the optical waveguide between the first contact and the optical path of the optical beam. A buffer plug of insulating material disposed in the optical waveguide on a same side as the first location.

Abstract: Apparatus for providing a laser source optically coupled to an optical waveguide, such as an optical fiber, having a reflective grating positioned from the output facet of the laser source a distance equal to or greater than the coherence length of the laser source providing a portion of reflective feedback into the laser source optical cavity to maintain wavelength operation of the laser source in spite of changes in the laser operating temperature or drive current based upon coherence collapse in the laser operation. In cases where the fiber grating is positioned in the fiber within the coherence length of the laser source, intermittent coherence collapse, as opposed to continuous coherence collapse, is unavoidable. In cases where such a laser source is a pumping source for a solid state gain medium, such as an optical amplifier or laser having an active gain element, e.g.

Abstract: A continuous wave(CW) activator ion doped fiber laser is presented which lases at a normally self-terminating laser transition at a slope efficiency greater than that achieved by a self-terminating fiber laser. Two laser transitions, one corresponding to a self-terminating laser transition and the other to a transition out of the lower level of the self-terminating transition, are simultaneously stimulated in the activator ion doped fiber. Through simultaneous lasing of the two wavelengths corresponding to these transitions, the lower level of the self-terminating transition is sufficiently depopulated so that CW operation is achieved.

Abstract: Continuous laser action is sustained by a new pumping mechanism which relies exclusively on cooperative electronic transitions of coupled atoms or ions in solids. The present invention is the first of a new class of laser device which depends on energy-sharing interactions between colliding atoms in gases or active dopants in solid laser media to create the population inversion needed for amplification of light. In one specific embodiment, a laser crystal which is formed of calcium fluoride is doped heavily with trivalent erbium, and is provided with reflective coatings on respective first and second surfaces. A pumping energy is supplied whereby a pair of atoms are elevated to an initial excited state. Subsequently, one of the atoms loses energy so as to assume a ground state, the energy released thereby being made available to excite the second atom to a still higher quantum energy state.

Abstract: A room temperature solid state laser for producing a laser emission at a wavelength of substantially 1.96 microns is disclosed. In a preferred embodiment, the laser includes: a laser cavity defined by a plurality of coated reflective elements to form a reflective path thereamong; a laser crystal disposed in the laser cavity and capable of lasing at substantially 1.96 mircons and 2.01 microns when excited; and means for exciting the laser crystal to lase at substantially 1.96 microns and at substantially 2.01 microns. The laser crystal is comprised of a host crystal material capable of accepting Cr.sup.3+ and Tm.sup.3+ ions. Through their respective reflectivities at each of the wavelengths at substantially 1.96 microns and 2.01 microns, the coated reflective elements collectively operate to produce substantial loss in radiation at the wavelength of substantially 2.

Abstract: A chemical process yielding stimulated emission of visible radiation via fast rear resonant intermolecular energy transfer comprising the steps of reacting a first metal or semimetal vapor with a reactant to produce a metastable excited state reaction product and transferring energy stored in the metastable excited state of the reaction product to a second metal or semimetal vapor by means of near resonant energy transfer to form electronically excited receptor atoms in a population inversion relative to a lower level of excitation of the receptor atoms. In the preferred form of the process, the first metal or semimetal vapor is a group IIIA or IVA element. The second metal or semimetal vapor is of a group IIA or IVA element and the reactant is either ozone, nitrogen oxide, nitrogen dioxide or a halide.

Abstract: A method for creating population inversions for use in stimulated emission devices which beam combine, beam clean-up, or frequency up-convert electromagnetic radiation. The invention comprises near resonantly enhanced multiphoton pumping of a multilevel quantum medium with pump beams of appropriate intensities and frequencies detuned from the transition frequencies of the medium. The intensities are orders of magnitude lower than those required for non-resonantly enhanced multiphoton pumping. The detuning is smaller for the maximum multiphoton resonance than for the single photon resonances. Appropriate medium decay constants are required for creating a population inversion between energy levels of the quantum medium. The population inversion exists between energy levels of the medium whose energy difference may exceed the energy of any single pump photon energy.

Abstract: The method of producing at least quasi-continuous lasing operation between initial and terminal lasing states comprising the steps of selecting a laser medium and cavity configuration (lasing frequency) with the laser medium containing upconverting material which provides for the exchange of energy between sufficient number of electrons at the terminal lasing state (manifold) so as to maintain population inversion between the initial and terminal lasing states during the lasing operation; and applying excitation energy of a suitable amount to the laser medium during at least a quasi-continuous time period.

Abstract: Stimulated emission at the approximate wave length of 4.5 microns, 2.25 microns and 1.6 microns is obtained from pumping on an excited energy level. The phenomenon of photon avalanching is utilized to create a population inversion within three lower level states that have a substantially equal energy spacing to provide resonance between neighboring ions. This resonance feeds the photon avalanching process when pump having sufficient power in excess of the critical pump power irradiates a LaCl.sub.3 :Pr.sup.+3 crystal at an excited energy level to maintain a population inversion in an optical cavity.

Abstract: Stimulated emission resulting from a secondary source of radiation transfers population from a lower laser level of a primary lasing transition to a third energy level which is not involved in the primary lasing of a laser system to reduce lower laser level bottlenecking.

Abstract: The method of generating XUV radiation which involves exciting atoms to a storage level, irradiating the excited atoms and raising them to a higher level and allowing the atoms to lase to a lower level other than ground which is simultaneously emptied.

Abstract: The operation of a two-photon, three level laser system at high temperatures or pressures is made possible by reducing the build up time of the flux of the second lasing transition in the laser discharge region.

Abstract: A technique for lasing a gas in a gas lasing device to obtain stimulated light emission at a desired wavelength by bottlenecking the high gain transitions in the gas so that certain low gain transitions which will yield the desired wavelength are now able to oscillate. This technique comprises the steps of optimizing the mirror transmission for the desired light frequency, and pumping the laser gas with a pulse whose width is much longer than that required to bottleneck the high gain transitions. This technique may be utilized with both molecular and atomic gases.

Abstract: A laser having a gaseous mixture including carbon dioxide as the lasing medium, wherein the lasing medium is cooled to a temperature such that the thermal population of the lower energy level of an output lasing transition between a higher energy level and a lower energy level of the carbon dioxide molecule is reduced, and the lasing medium is initially energised to create the population inversion which results in the lasting transition at a rate such that significant thermal population of the lower energy level is avoided.