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Quantum Electronics, IEEE Journal of

Issue 9 • Date September 1981

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Displaying Results 1 - 25 of 50
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • Frequency locking in double-pumped dye laser

    Page(s): 1591 - 1592
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    A jet-stream dye laser was pumped simultaneously by a CW argon laser and a high-power xenon ion laser. The frequency and bandwidth of the pulsed radiation obtained were locked to the CW radiation inside the folded cavity. View full abstract»

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  • Foreword to the speacial issue on lasers on fusion

    Page(s): 1598
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    Freely Available from IEEE
  • The Shiva laser-fusion facility

    Page(s): 1599 - 1619
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    The 10 kJ Shiva laser irradiation facility is a major laser experimental facility devoted to inertial confinement fusion (ICF) research. It consists of: 1) a 20-beam Nd:glass laser amplifier system in which each beam has a final clear aperture of 20 cm diameter, 2) optical and alignment systems to focus the 20 beams simultaneously onto microscopic fusion targets, and 3) target diagnostics systems to measure the response of the targets to the irradiating beams. Since its activation in early 1978, Shiva has operated continuously, providing up to 28 terawatts (TW) of 1.064 μm optical power to targets. The evolution of Shiva into a reliable experimental facility required the development of engineering technology based on solid-state laser concepts first introduced in the 1960's and early 1970's. View full abstract»

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  • Vulcan - A versatile high-power glass laser for multiuser experiments

    Page(s): 1653 - 1661
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    This paper reports the design and characterization of the newly upgraded Nd:glass laser facility at the Rutherford Laboratory. Emphasis is placed on the unusual aspects consequent on its role as a multiuser facility, where reliability and flexibility are of paramount importance. The basic facility configuration is of two high-power laser systems in parallel-a six-beam laser for implosion experiments and a separate high-power single beamline for either X-ray backlighting diagnostics of implosion experiments or use in a separate single-beam target area. Additional flexibility is provided by remotely controlled changeover mirrors enabling groups of amplifiers to be used in different combinations for various energies and shot repetition rates. Either a mode-locked or aQ-switched oscillator can be selected to provide a range of pulse durations from 50 ps to many nanoseconds. Harmonic generation is used routinely to give a choice of wavelengths for different experiments. The six-beam system is normally run at the second harmonic, although the fundamental wavelength is also available, while the single-beam target area can use fundamental, second, or third harmonics. View full abstract»

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  • A long-pulse/short-pulse synchronization scheme using a regenerative amplifier and high-voltage semiconductor switching

    Page(s): 1709 - 1712
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    A scheme synchronizing a long and a short laser pulse is presented. High-voltage semiconductor switching techniques have the timing precision to allow a very short regenerative amplifier cavity, which in turn minimizes the delay between the long and the short pulse. Emphasis is put on shot-to-shot reproducibility and the long-pulse limit of the system. View full abstract»

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  • A pulsed and quasi-CW actively mode-locked Nd:phosphate glass oscillator

    Page(s): 1723 - 1726
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    Active mode locking was realized in pulsed and quasi-CW modes with an Nd:phosphate glass of low thermooptical coefficient as an active medium. The quasi-CW current of rectangular waveform was supplied by an inhomogeneousLCforming network. Experimental results on the mode-locked pulse train, pulsewidth, spectral linewidth, relaxation oscillation, and gainQ-switching are given. View full abstract»

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  • Active-mirror amplifiers: Progress and prospects

    Page(s): 1755 - 1765
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    Active-mirror amplifiers have been demonstrated to be viable amplifiers for use in high peak power/energy Nd:glass laser systems [1], [2]. In addition to having a rather large storage efficiency, they may be used in systems requiring a medium-repetition rate and possess desirable thermal properties for application in double-passed or regenerative amplifier architectures. Here, we review recent progress made in the development and deployment of active-mirror amplifiers, examine their potential storage and overall system efficiencies, and outline the technological progress needed for their development as high-repetition rate (1-10 Hz) amplifiers. View full abstract»

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  • A two-pass three-channel slab amplifier

    Page(s): 1766 - 1768
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    A highly efficient slab amplifier has been designed. It has an aperture of 100 mm. The laser beam passes through the amplifier via three channels and then goes through it for the second time. Under typical conditions, we have obtained a gain of tenfold, an output intensity of 1011W [1], and an efficiency of 0.1 percent. By means of astigmatism compensation, the statical beam divergence after passing through 72 surfaces has been improved to 60 μrad, and the dynamic beam divergence to 0.2 mrad. View full abstract»

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  • Advanced iodine laser concepts

    Page(s): 1809 - 1816
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    The essential features of an advanced iodine laser are outlined. These are governed primarily by the proper choice of the stored inversion density of an amplifier and also by the means to enhance the energy extraction efficiency to values in excess of 50 percent. With these measures an amplifier chain with output energies in the kJ range and overall system efficiencies of almost 0.2 percent can be designed. This value is twice as high as that now achieved. As the laser-fusion experiments require a greater pulse duration variability than hitherto obtained, an oscillator pumped by an excimer laser is developed, allowing chain output pulse durations in the range from some 100 ps to several ns. The frequency conversion of iodine laser light by nonlinear interaction in crystals is also investigated. View full abstract»

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  • A conceptual design of a hydrogen-fluoride chemical laser driver for inertial confinement fusion

    Page(s): 1840 - 1847
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    This paper summarizes the results of a study which assessed the potential of the hydrogen-fluoride (HF) chemical laser as a laser-fusion driver. The evaluation was made by designing a laser system in sufficient detail that potential problems could be identified. A summary of the laser design including amplifier parameters, electron-beam accelerator specifications, gas-handling system, pulse shape considerations, and net efficiency calculations is presented here. The final laser design consists of 20, 100 kJ final amplifiers, which combine to yield a 2 MJ laser output. The energy is delivered in a shaped pulse in which one-half of the energy is delivered in the last 3 ns. The pulse rate is 4 pulses per second and the net efficiency is approximately 3 percent. Consideration is also given to the consequences of varying certain laser parameters. The general conclusion obtained from this study is that the HF laser is an attractive laser candidate for laser-fusion applications. View full abstract»

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  • A self-consistent static model of the double- heterostructure laser

    Page(s): 1941 - 1949
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    A new static model of the double-heterostructure laser is presented which treats the p-n junction in the laser in a consistent manner. The solution makes use of the finite-element method to treat complex diode geometries. The model is valid above lasing threshold and shows both the saturation in the diode junction voltage at threshold as well as lateral mode shifts associated with spatial hole burning. Several geometries have been analyzed and some specific results are presented as illustration. View full abstract»

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  • An optimization procedure for the selection of diode laser facet coatings

    Page(s): 1950 - 1954
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    The relationship between the facet reflector properties and the steady-state power-current characteristics of diode lasers is analyzed. A general procedure is developed for calculating the facet reflectance values that optimize the electrical-to-optical power conversion efficiency of a diode laser emitting a specified value of optical power. Numerical examples are presented which apply this technique to the selection of facet coatings for a typical diode laser. The diode laser with optimized facet reflectances is shown to have lower internal power dissipation than devices with uncoated or half-wave coated facets. The properties of Al2O3/Si multilayer facet coatings are investigated, with special attention given to the effects produced by optical absorption in the amorphous silicon layers. View full abstract»

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  • Analysis of electrical, threshold, and temperature characteristics of InGaAsP/InP double- heterojunction lasers

    Page(s): 1954 - 1963
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    This paper presents an extensive study of the fundamental characteristics of InGaAsP/InP double-heterojunction (DH) lasers with a wavelength of 1.3 μm. The confinement properties of injected carriers in the quaternary active region, the electrical properties such as leakage current and diode current versus voltage, the threshold characteristics, and the threshold temperature characteristics are determined through an analysis of the heterojunction energy band structure. The threshold temperature characteristics and the carrier leakage from the active region into the confining layers are examined in detail. To clarify the dependence of carrier leakage on lasing wavelength in InGaAsP/InP DH lasers and to explain the difference between GaAlAs/GaAs DH and InGaAsP/InP DH lasers, the barrier heights required to effectively confine the injected carriers and the effective carrier masses in the active region are discussed. Various possible explanations for the observed threshold temperature characteristics are considered. View full abstract»

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  • [Back cover]

    Page(s): 0
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    Freely Available from IEEE
  • Basic properties of KDP related to the frequency conversion of 1 µm laser radiation

    Page(s): 1782 - 1786
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    We present calculations of various basic properties of KDP related to the generation of the second, third, and fourth harmonics of 1 μm laser radiation. For five different conversion processes we tabulate the phase-matching angles, the sensitivities to angular mismatch, wavelength and temperature, and related quantities. All calculations are based on experimentally determined refractive indexes and refractive-index temperature derivatives. Calculations are compared with recent experimental results whenever possible, and are generally in good agreement. View full abstract»

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  • Gaseous saturable absorbers for the helios CO2laser system

    Page(s): 1799 - 1808
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    Saturable absorbers are widely used to suppress parasitic oscillations in large-aperture, high-power CO2fusion-laser systems. We report experimental results on SF6-based gaseous saturable absorbers used for parasitic suppression in the eight-beam, 10 kJ Helios fusion-laser system. The gas mix effectively quenches self-lasing in the 9 and 10 μm branches of the CO2laser spectrum while simultaneously allowing high transmission of subnanosecond multiwavelength pulses for target-irradiation experiments. The gas isolator now in use consists of SF6and the additional fluorocarbons: 1, 1-difluoroethane (FC-152a); dichlorodifluoromethane (FC-12); chloropentafluoroethane (FC-115); 1,1-dichloro 2, 2-difluoroethylene (FC-1112a); chlorotrifluoroethylene (FC- 1113); and perfluorocyclobutane (FC-C318). The saturation of the mix was studied as a function of incident fluence, pressure, cell length, and incident wavelength. Experimental results are presented on the saturation properties of pure SF6and FC-152a and compared with the saturation behavior of CO2at 400°C. View full abstract»

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  • Optical probe observations of nonuniformities in laser-produced plasmas

    Page(s): 1909 - 1917
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    Due to its high spatial and temporal resolution, optical probing is a very powerful technique for investigating the corona plasma of laser-heated targets. The basic requirements of optical probing systems are discussed and a short description of a system presently in use is given. Various experimental observations are presented of results obtained with this system on targets irradiated with long pulses of low (sim 10^{13}W . cm-2) irradiance as are used in ablatively driven compression experiments. These show the presence of small-scale density and magnetic-field nonuniformities in the plasma corona. View full abstract»

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  • Light propagation through large laser systems

    Page(s): 1727 - 1744
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    The evolution of solid-state laser systems over the past decade, both through technological advances and through increased understanding of the interplay between nonlinear effects and linear diffraction, is reviewed. The role of numerical methods to simulate the several physical processes (diffraction, self-focusing, gain saturation) involved in coherent beam propagation through large laser systems is discussed. A comprehensive simulation code for modeling all of the pertinent physical phenomena observed in laser operations (growth of small-scale modulation, spatial filtering, imaging, gain saturation, and beam-induced damage) is described in detail. The realism and accuracy of results obtained with this numerical code stem from an unambiguous identification of the sources of spatial noise, and from the use of spatial filters in modern lasers to limit the transverse beam modulation scale within the practical computational range of a two-dimensional numerical analysis. Several comparisons between code results and solid-state laser output performance data are presented. Finally, the design and performance estimation of the large Nova laser system presently under construction at the Lawrence Livermore National Laboratory (LLNL) are given. View full abstract»

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  • GDL: A high-power 0.35 µm laser irradiation facility

    Page(s): 1689 - 1693
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    The glass development laser (GDL) single beam 0.35 μm laser irradiation facility is now operational at the Laboratory for Laser Energetics of the University of Rochester. The system is based on a frequency tripled Nd:phosphate glass laser and is capable of generating in excess of 200 GW in 100 ps and 54 J in 0.5 ns pulses at 0.35 μm. A discussion of the system design, performance, and applications is presented in this paper. View full abstract»

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  • Bidirectional amplification with nonsaturable absorption and amplified spontaneous emission

    Page(s): 1879 - 1887
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    A theory of bidirectional amplification is developed and applied to single-pass and double-pass laser amplifier configurations. The effects of nonsaturable absorption, longitudinal amplified spontaneous emission (ASE) gain saturation, and ASE line narrowing are included in a self-consistent formulation. An estimate of aperture scaling limitations due to transverse ASE is included. Laser performance is discussed for some conditions typical of large aperture, multikilojoule, rare gas halide (RGH) fusion amplifiers. This formulation permits tradeoff studies to be performed rapidly by altering variables spanning an eight-parameter space. View full abstract»

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  • Discharge and kinetics modeling in electron-beam controlled CO2laser amplifiers

    Page(s): 1786 - 1799
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    The specific computational methods used to model the spatial and temporal behavior of large pulsed electron-beam controlled CO2laser amplifiers are presented. The interactions between the various physical processes which occur in these devices are related to the logical structure of the model, so that the key approximations can be identified. We show that, in most cases, the uniformity of the gain can be adequately described with a two-dimensional (2-D) analysis, which uses the discharge conditions present at a single "snapshot" time corresponding to the peak of the discharge power. We apply these techniques to model an experiment in which the nonuniformities play an important role; and, as a second example, we demonstrate that the modeling capabilities can show the consequences of design modifications in large-aperture amplifiers. View full abstract»

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  • Laser-induced surface and coating damage

    Page(s): 1888 - 1903
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    Results from experiments on laser-induced damage to surfaces of optically polished glass and fused-silica and thin-film coatings are presented. Measurements were made under proper conditions to characterize actual laser components. Data are given for distributions of thresholds for 1.06 μm, 1 ns pulses, the influence of coating materials and designs, and effects of surface preparation on damage threshold, variations of threshold with duration of the laser pulse, and thresholds for selected visible and ultraviolet wavelength pulses. View full abstract»

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  • Omega automated laser control and data acquisition

    Page(s): 1903 - 1908
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    This paper describes a computing system which is an integral component of a large and complex laser system. The computing system is dedicated to real-time control, data acquisition, analysis, and display. The computing and laser systems evolved simultaneously, resulting in a very close coupling between both systems. The computing system has been divided into a number of subsystems including power conditioning, alignment, diagnostic data acquisition, and data reduction. These subsystems operate almost autonomously, resulting in the reliability inherent with loosely coupled noninterfering computers. The system and its subsystems are described, including details about the laser system where appropriate. View full abstract»

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  • Development of high-power laser system for laser-fusion research

    Page(s): 1650 - 1653
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    This paper reviews the development of high-power Nd:glass laser techniques for laser-fusion research in China since 1965, including the construction of single- and multiple-beam laser systems, the development of various laser oscillators, amplifiers, components, and some other special optical techniques. View full abstract»

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Aims & Scope

The IEEE Journal of Quantum Electronics is dedicated to the publication of manuscripts reporting novel experimental or theoretical results in the broad field of the science and technology of quantum electronics..

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Aaron R. Hawkins
Brigham Young University