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Quantum Electronics, IEEE Journal of

Issue 7 • Date July 1972

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Displaying Results 1 - 14 of 14
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • High-radiance room-temperature GaAs laser with controlled radiation in a single transverse mode

    Page(s): 632 - 641
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    A GaAs laser for room-temperature operation is reported with high radiance and short delay times. For high radiance, the radiation of a 200-μ-wide GaAs laser diode is confined to the lowest order transverse mode. This is accomplished by operating the laser diode with an optical cavity in which the transverse mode is controlled by aperture-limiting slits. In the cavity, built of spherical lenses and plane mirrors, the mode width and height coincide with the width and height of the active region of the injection laser. The diffraction losses of the higher order transverse modes introduced by the apertures are sufficiently high to yield controlled radiation in the TEM00mode ; this control was not always assured in the earlier design of the GaAs laser with the external resonator [1]. For short delays of the onset of stimulated emission, GaAs lasers are used for which the transition from short to long delays occurs above room temperature. Also, the external cavity is coupled closer to the active region of the semiconductor diode than reported previously [1] to minimize losses that would increase the delay times. Test results on the radiance, room-temperature delay times, and mode structure of the GaAs laser with the optical cavity are presented and the observed spiking pattern is discussed. View full abstract»

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  • CW operation in some CO lines below 5.0 µ

    Page(s): 679
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    CW laser emission has been observed from a He-N2- O2-CO laser on six vibration-rotation lines of carbon monoxide that lie below 5.0 μ. The lines correspond toV = 3:2andV = 4:3transitions. View full abstract»

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  • [Back cover]

    Page(s): 0
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    Freely Available from IEEE
  • The role of excited states in multiphoton ionization

    Page(s): 623 - 631
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    The mixing of the excited states of an atom with the ionization continuum is considered by a modification of Fano's theory of autoionization. It is shown that in the case of the noble gases this leads to a reduction of the threshold power-law indexKfromI/hbaromegatoE_{n}/hbaromega(whereIis the ionization energy, Enthe lowest excited state energy, andhbaromegathe photon energy) as found experimentally. View full abstract»

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  • Measurements of device parameters for Nd:YAlO3lasers

    Page(s): 669 - 674
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    This paper presents measurements of several properties of Nd:YAlO3useful in the design of laser devices. Values for the gains, cross sections, and saturation parameter of the4F_{3/2} rightarrow 4I_{11/2}transitions are presented for principal axis polarizations. Thermal focal lengths, spherical aberration, and astigmatism forA-, B-, andC-axis rodsfrac{1}{4}in in diameter and 3 in long are shown as a function of input power. Pumping efficiencies with krypton and xenon lamps are compared for Nd:YAG, Nd:Cr:YAlO3, and Nd: YAlO3both in the CW and flash-pumped modes. Finally, the effects of varying the Nd concentration in YAlO3from 0.4 to 1.15 percent are discussed. View full abstract»

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  • Output fluctuations of CW-pumped Nd:YAG lasers

    Page(s): 656 - 661
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    The mechanisms that cause amplitude modulation in CW-pumped YAG lasers were investigated experimentally. The depth of modulation and frequency spectrum of the output fluctuations of a commercially available Nd:YAG laser were measured. It was found that after performing several modifications on the laser system, the output fluctuations were reduced by two orders of magnitude. At the conclusion of the program, the depth of modulation for frequencies below 10 Hz was 10-2, and for frequencies between 10 Hz and 100 kHz, it was 10-3. Above 100 kHz, the modulation decreased rapidly to 10-5reaching shot noise level above 500 kHz. View full abstract»

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  • Gain and relaxation studies in transversely excited HF lasers

    Page(s): 651 - 655
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    The results of measurements of the spatial and temporal dependence of the gain of a pulsed HF laser are reported and are compared with those for CO2lasers. While the propagation in space of a locally excited gain medium is observed to be comparable for the two lasers, the time developments are vastly different. The extremely fast gain decay rates that were observed in the HF laser are shown to be a serious detriment to efficient high-power CW or long-pulse operation. Short pulse HF lasers, however, can be operated relatively efficiently at high energies. This was demonstrated by obtaining 350-mJ pulses from a 75-cm "pin" laser excited by 50-ns pulses from a Marx bank. View full abstract»

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  • CW laser oscillation at 6127 Å in singly ionized iodine

    Page(s): 679 - 680
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    CW laser action has been obtained on the 6127-Å transition ofI(II) in a He-CdI2discharge. Relative output power has been measured as a function of discharge current, helium pressure, and CdI2temperature. View full abstract»

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  • High-repetition-rate continuously pumped ruby laser

    Page(s): 675 - 676
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    The first successful operation of a high-repetition-rate repetitivelyQ-switched ruby laser is reported. Using an acousto-opticQswitch, repetition rates up to 5000 pps have been achieved. When the laser is optimized, peak power outputs of 20 kW at 500 pps and 8 kW at 2000 pps can be expected. View full abstract»

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  • Passive Q switching of a CO2laser near 9.2 µ using CF2Cl2

    Page(s): 676 - 677
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    CF2Cl2is found to cause passiveQswitching on practically all of the lines in theRbranch of the00deg1-02deg0vibrational-rotational band of CO2. View full abstract»

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  • Hollow dielectric waveguide for distributed feedback lasers

    Page(s): 661 - 669
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    Hollow dielectric waveguides with gas-filled core and a dielectric tube seem promising as laser structures. The tube fulfills the dual role of a guidance structure for the electromagnetic radiation as well as that of a container for the plasma of the gas laser. Feedback for laser oscillation is achieved by providing coupling between forward- and backward-traveling modes by means of periodic ripples of the inner surface of the hollow dielectric tube. This paper is devoted to the derivation of the coupling coefficients between two guided modes that are coupled by ripples in the tube wall. The calculation is based on the model of a slab waveguide. Expressions for the leaky-mode losses and the scattering losses inevitably introduced by the coupling mechanism are also presented. View full abstract»

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  • Hybrid injection locking of higher power CO2lasers

    Page(s): 641 - 650
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    Frequency stabilization of a higher power CO2ring laser by locking with a stable low-power reference laser is described. Successful locking is achieved by employing a novel hybrid injection-locking technique. In the hybrid mode, the higher power laser is tuned to operate on a self-oscillation line different from that of the reference laser. Within the frequency-locking range, the self-oscillation of the locked laser is completely quenched, and only the amplified drive power of the locking laser appears. Operation of this hybrid technique relies on the line competition in the homogeneously broadened CO2medium. The hybrid technique, which is easily implemented with a simple hill-climbing servo, permits stabilized operation over a variety of laser lines. An analysis of injection locking that explicity includes the saturation of the homogeneous medium is presented. Expressions are obtained for the gain and the phase relationships within and outside the locking region. To demonstrate the potential of the hybrid injection-locking technique, a 60-W CO2laser was locked in frequency to a 0.5-W stable oscillator. The experimental data are in close agreement with theory. View full abstract»

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  • Far-infrared laser emission from H2CO in a large gas-laser tube

    Page(s): 677 - 679
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    Far-infrared laser emission from H2CO in the sealed-off operation has been obtained with a large gas-laser tube. This emission has been observed from the beginning of discharge to several tens of pulses under pulsed electrical excitation. The emission lines were 102, 119, 122, and 159 μm. 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