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Quantum Electronics, IEEE Journal of

Issue 5 • Date May 1969

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Displaying Results 1 - 11 of 11
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • A comparison of rare-gas flashlamps

    Page(s): 232 - 237
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    Spectral data for argon, krypton, xenon, and neon flashlamps are presented for the region of lamp operation in which the line radiation makes up a substantial portion of the total radiant energy. The spectral charateristics are presented in terms of both power flux and emitted quanta per unit area per second, the latter being appropriate for the characterization of illumination and laser pumping efficiencies. The emission spectra show strong line radiation peculiar to each gas superimposed on a low emissivity background continuum. The electrical resistance coefficientk (in Omega.A^{1/2})is presented for each gas and is shown to increase with increasing gas atomic weight and pressure. An analysis of lamp radiative efficiency indicates that through proper optimization of the gas pressure, the efficiency and overall output of the lighter rare gases will be comparable to those for optimized xenon lamps with optimum pressures increasing with decreasing gas atomic weight. Overall lamp efficiencies are shown to be as high as 40 percent in the0.4-1.1-muregion. View full abstract»

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  • Photon echoes and combination tones - A comparison between their polarization dependence

    Page(s): 246 - 249
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    The effects of level degeneracy on the polarization dependence of photon echoes and of combination tones in gases are compared. A remarkable similarity in behavior is found to exists, with quantitative agreement in the case of several simple transitions. By analogy, the echo behavior for elliptically polarized input pulses is suggested. View full abstract»

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  • Π-pulse propagation in the presence of host dispersion

    Page(s): 249 - 259
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    A steady-state solution describingPi-pulse propagation in a homogeneously broadened laser amplifier embedded in a dispersive lossy host is found. For a given model of dispersion, the solution satisfies exactly the second-order wave equation together with the equations of motion for the density matrix of the two-level resonant system. The salient feature of the solution is that a small amount of dispersion in the host group velocity causes a large monotonic frequency sweep during the pulse. The effects of this chirp on the pulse properties are described in detail, and the relation of the theory to experiments is discussed. View full abstract»

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  • [Back cover]

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    Freely Available from IEEE
  • Efficient Nd: YAG CW lasers using alkali additive lamps

    Page(s): 238 - 241
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    A potassium-mercury lamp in a sapphire envelope was constructed. Under the proper conditions of pressure and temperature the potassium resonance lines radiate efficiently at the infrared absorption lines of Nd3+in YAG. Spectral tests indicate that a threefold improvement in pumping efficiency should be obtained compared with a tungsten filament lamp. CW room-temperature laser tests result in an output of 10 watts for an input of 420 watts for a 2.4 percent overall efficiency. This compares with a 1 percent overall efficiency for the tungsten filament lamp. View full abstract»

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  • Rare-Gas pumping efficiencies for neodymium lasers

    Page(s): 225 - 231
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    A comparison of rare-gas flashlamps for pumping YAG: Nd3+and neodymium-doped glass, which shows krypton lamps to be superior to xenon under certain circumstances, is presented. The emission spectra of argon have the best match to the neodymium absorption spectra, but argon lamps suffer from low radiative efficiency except at very high pressures. A detailed analysis of theoretical laser thresholds, which takes into account pump-pulse duration, cavity transfer coefficient, laser rod diameter, lamp emission spectra, and other pertinent parameters, is compared to experimental threshold data with good agreement. Krypton at 500-mm pressure gives a 19-percent improvement in the YAG : Nd3+threshold over a comparable xenon lamp at low current densities. Xenon is generally superior to krypton for pumping glass rods because of the greater absorption at 5900 Å where xenon is intrinsically a better radiator. However, proper lamp optimization shows a definite improvement in threshold with krypton at low drive levels. Xenon is anticipated to be superior to krypton at high current densities since line radiation will no longer contribute significantly to the pumping process. Proper optimization of lamp and cavity parameters should permit a slope efficiency of ∼6 percent for neodymium lasers to be realized. View full abstract»

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  • Multiple mode locking of lasers

    Page(s): 219 - 225
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    Details of experimental results on higher order phase-locking phenomena of a He-Ne laser with a fixed cavity length and a fixed position of the laser tube in the cavity are presented. Two methods have been used in the experiments in order to obtain high bit-rate optical pulses. In one method modified Michelson-type resonators and a three-mirror Fabry-Perot resonator are utilized to suppress the oscillation of the undesired modes. Optical pulses of repetition rates up to about 600 megabits/s have been obtained. The second method utilizes an internal phase perturbation in a conventional Fabry-Perot cavity at a frequency nearly equal to a multiple of the longitudinal mode spacing. The repetition rate of optical pulses generated does not always coincide with the modulation frequency, but depends on the fine tuning of the frequency. In contrast to the former method, mode quenching is not necessarily required to produce multiple-bit pulses. View full abstract»

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  • Role of optical flux and of current density in gradual degradation of GaAs injection lasers

    Page(s): 242 - 245
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    A GaAs dual-diode laser structure was used to give electrical control of the laser threshold and so permit separate study of the effect of optical flux on gradual degradation. At a given current density, degradation occurs under nonlasing conditions at about the same rate as under normal lasing conditions. The degradation rate is a superlinear function of current density. Degradation is an erratic process in which the rate varies sporadically during operation. 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..

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Meet Our Editors

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