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Quantum Electronics, IEEE Journal of

Issue 7 • Date July 1974

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Displaying Results 1 - 12 of 12
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • Silver thiogallate (AgGaS2) - Part 1: Nonlinear optical properties

    Page(s): 540 - 545
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    The first part of a collaborative survey of the linear and nonlinear optical properties of silver thiogallate, carried out by the Centre National d'Etudes des Télécommunications (Bagneux) and the Department of Electronics of the University of Southampton, is presented. A detailed study of second-harmonic generation (SHG) in silver thiogallate is presented. Careful experiments in the near and medium infrared lead to a new determination of the coefficient|d_{36}|. Comparison is made with previously published values. Crystal quality is discussed and the nature of the visible twinning defects elucidated. View full abstract»

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  • Silver thiogallate (AgGaS2) - Part II: Linear optical properties

    Page(s): 546 - 550
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    New measurements are presented on the absorption of silver thiogallate and related to fundamental mechanisms. All available data on the refractive indices of silver thiogallate, including new results for the visible, have been incorporated into sets of Sellmeier expressions. Different Sellmeier constants are given for visible and infrared wavelengths and also for crystals from different sources. Confirmation of some predictions from these Sellmeier expressions has been obtained by second-harmonic generation (SHG) experiments with a tunable optical parametric oscillator. Preliminary results on laser damage are summarized. View full abstract»

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  • Analysis of heterojunction optical waveguides with a modulated region smaller than the guide width

    Page(s): 551 - 556
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    Heterojunction optical waveguide modulators in which the modulated region may be smaller than the guide width are analyzed using two models: the average-field model, which replaces the actual junction field with a uniform field and the abrupt-junction model, which accounts for the linear decrease of the electric field throughout the depletion region. The models are used to calculate the field-induced birefringence in two (Ga,Al)P heterojunction waveguide structures as a function of voltage, including the effects of the change in the depletion width, and the results are compared. Both models predict a mode dependence for the induced birefringence which is especially strong for thin modulated regions. View full abstract»

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  • [Back cover]

    Page(s): 0
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    Freely Available from IEEE
  • Field-realigned nematic-liquid-crystal optical waveguides

    Page(s): 556 - 562
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    An external electric field exerts volume torque on the nematic liquid crystal due to the anisotropic molecular polarizability and tends to reorient the molecular axes. Phase-velocity tuning in these materials is thus possible. Eigenmodes of thin-film liquid-crystal waveguides are analyzed by a numerical method. A three-layer model of the waveguides is found to be in good agreement with the measured data, thus providing a simplified model for conceptual thinking as well as for computation. View full abstract»

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  • Subnanosecond rise time pulses from injection lasers

    Page(s): 570 - 572
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    The hybrid integration of an injection laser with a simple avalanche transistor modulator is shown to produce optical peak powers of several tens of watts magnitude and pulse rise times appreciably shorter than 1 ns. In certain circumstances the pulse leading edge assumes the form of a spike having a displayed rise time of 120 ps. View full abstract»

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  • The GaAs P-N-P-N laser diode

    Page(s): 567 - 569
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    The general structure of double-heterojunction diode lasers is shown to be consistent with the required geometry of the Shockley diode or p-n-p-n switch. When the two devices are combined in a single structure, there results an extremely simple source of high optical power (>0.5-W) pulses of very short duration (<10 ns) without the need for a complex external driver. In principle, pulse triggering and repetition rate are easily controlled, suggesting that the device has potential application in pulse-coded optical communication systems. View full abstract»

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  • Molecular saturation and the criterion for passive Q switching

    Page(s): 533 - 540
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    Rotational hole burning is known to be the main factor that determines saturation in molecular absorbers during a short pulse. Experimental results are presented that suggest that pulse transmission measurements, as opposed to CW transmission measurements, must be used in order to determine if a gas can be used as a saturable absorber in passiveQswitching. Rate equations are developed for a five-state model to explain saturation in SF6. This model is found to predict CW and pulse transmission through SF6at various lines of the 10.4-μm band of the CO2laser. A simplified model is developed for pulse transmission through saturable gases and is solved analytically for the peak of the pulse. It is found that the absorption coefficient of the absorber at the peak of the pulse is given by a simple expression, which leads directly to a new criterion for passiveQswitching. An experimental test of this criterion is carried out for several mixtures of SF6and He which act as saturable absorbers under varying conditions of irradiation. It is found that the transition from CW to pulsed operation is very sharp and occurs at a well-defined value of radiation intensity. View full abstract»

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  • Extinction ratios of GaAs and CdTe electrooptical modulators

    Page(s): 572 - 573
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    Comparative extinction-ratio measurements for two electrooptical materials, GaAs and CdTe, are reported. The extinction ratio obtainable in the two materials is found to be similar, with the best samples approaching 104:1. View full abstract»

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  • Emission cross section and fluorescence efficiency of Nd-pentaphosphate

    Page(s): 563 - 567
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    The room-temperature cross sections for the Nd3+4F_{3/2}levels to the4I_{11/2}and4I_{9/2}manifolds (lower laser state and ground state, respectively) in NdP5O14are measured by two spectroscopic methods. A value for the largest cross section ofsigma(R_{1} - Y_{2}) = 1.7 times 10^{-19}cm2is found. The highest effective cross section, resulting from superposition of two lines at 1.051 μm, gives a laser gain per Nd ion which is about 2/3 of the maximum gain in YAG:Nd. The relative branching ratio into the4I_{11/2}and4I_{9/2}manifolds is 0.65:0.35. Comparison of the integrated cross sections with the measured lifetime for 1-percent Nd in LaP5O14indicates a combined efficiency <0.1 for the remaining transitions, namely radiative decay into the4I_{13/2}and4I_{15/2}manifolds and multiphonon quenching. A measurement of temperature dependence of fluorescence lifetime supports this last result. 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