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Quantum Electronics, IEEE Journal of

Issue 7 • Date July 1970

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Displaying Results 1 - 19 of 19
  • [Front cover and table of contents]

    Page(s): 0
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  • Pulse velocities in the self-locked He - Ne laser

    Page(s): 471 - 472
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    An experimental comparison of the pulse and group velocities in a self-pulsing ring laser is presented. It is found that the two velocities are essentially equal near laser threshold, and the group velocity exceeds the pulse velocity by an increasing amount for increasing laser excitation. View full abstract»

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  • [Back cover]

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    Freely Available from IEEE
  • Efficient CO2laser modulation internal to the cavity by methyl chloride gas

    Page(s): 472 - 473
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    Modulation of a CO2laser with a Stark cell internal to the cavity has been achieved with very low voltage and capacitance requirements-100 V/cm for 50 percent modulation and 50 percent absorptions with a capacitance of the order of 10 pF. View full abstract»

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  • Performance of broad-band microwave-biased extrinsic photoconductive detectors at 10.6 µ

    Page(s): 450 - 457
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    An analysis of the photoconductive gain-bandwidth product and SNR is presented, which allows a comparison of microwave-biased and dc-biased extrinsic detectors. The results of an experimental comparison using mercury-doped germanium at 10.6 μ are described. For equal bandwidth of 70 MHz, the measured gain and detectivity were better by a factor of 35 for microwave biasing compared to dc biasing. View full abstract»

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  • High-power pulsed xenon ion lasers

    Page(s): 466 - 469
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    Output and threshold characteristics of small-bore pulsed xenon ion lasers are presented in detail as a function of current and gas pressure for ranges of these parameters that are consistent with high optical power output in the green-blue spectral region. It has been found that six wavelengths characteristic of xenon exhibit peak output powers greater than 100 watts, from a 5-foot laser tube over a limited (8-24 mtorr) range of xenon tube pressure. Laser action has also been obtained at high peak powers for longer current pulse (5-50 mus) operation of the tube. In addition, observation of three new laser wavelengths 5340, 5501, and 5590 Å is reported. These lines are only observed at very low tube pressures and very high peak currents. View full abstract»

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  • Laser-light noise and current noise of GaAs CW laser diodes

    Page(s): 423 - 428
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    Experimental studies are presented of the random fluctuations of the laser light and of the diode current of continuous-wave multifilament GaAs laser diodes. Using the single-detector method, the intensity noise of the laser light of single, optically isolated filaments is measured in the central measuring frequency range 40 kHz-6 MHz. In the same frequency range, the intensity noise of the total laser light from one emitting face is also measured. The intensity noise of the laser light is found to depend strongly on the generation of lasing filaments in the p-n junction. The noise of the electrical excitation current depends also on the filamentary action. The laser-light noise and the current noise are correlated. The cross-correlation coefficient is measured between 40 kHz and 6 MHz as a function of the excitation current. The discovered correlation allows the application of a noise-modulation method to the laser light, which leads to a reduction of the laser-light noise-to-signal ratio. View full abstract»

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  • Passive Q switching of the CO2laser by C2H4gas and CH3OH vapor

    Page(s): 477 - 478
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    PassiveQswitching of the CO2laser in the 10.6-μ region using C2H4gas and in the 9.6-μ region using CH3OH vapor is reported. View full abstract»

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  • Rotational transition competition in a single-mode CO2laser

    Page(s): 462 - 466
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    In the present work we have investigated the mechanism of rotational transition competition of a single-mode laser by studying the effect of small variations of the out-coupling loss factor. For this purpose we used on the out-coupling side one extra mirror with a reflectivity of only 1 percent. In this way the instability problem could be followed with a controllable out-coupling device having a variable reflectivity between 73.6 and 81.5 percent and a corresponding variation in out-coupling loss factor. Due to the nonzero rotational relaxation time we find a narrow range of the gain-to-loss ratio of respective transitions to have nonsingle oscillations. We have observed single as well as multioscillating transitions as a function of the loss factor. View full abstract»

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  • Measurement of low-absorption coefficients using the beat frequency shift between transverse modes of a laser

    Page(s): 475 - 477
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    A new method of absorption measurement of liquids is presented. This method takes advantage of the shift in beat frequency between a strong Gaussian mode, forming a thermal lens in the liquid, and a weak first transverse mode acting as a probe to detect the thermal lens. The light absorption coefficients of the liquids are directly related to the beat frequency changes that are measured on an RF spectrum analyzer. The approach is general in that it can be used to measure the focal length of any weak lens. It appears to be more sensitive by nearly an order of magnitude than the methods that measure change in spot size. View full abstract»

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  • Intracavity polarization modulation of a nearly isotropic CO2laser

    Page(s): 457 - 462
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    A simple intracavity polarization-modulation technique is described that shows promise of producing nearly 100 percent amplitude modulation of laser output through the use of a relatively low-voltage electrooptic birefringent modulator. Some preliminary performance data are presented that support the general feasibility of the technique and indicate the direction that should be taken toward its further development. Although the technique is generally applicable to any CW laser system, it would appear to be particularly useful with the CO2laser since good electrooptic modulators are not available for that laser. View full abstract»

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  • Pulse velocity in a resonant absorber

    Page(s): 416 - 422
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    Experiments are reported that measure the pulse velocity of a mode-locked 6328-Å He-Ne laser pulse in a resonant absorber as a function of the pulse intensity. At low intensities, pulse velocities greater than the velocity of light in the passive medium are observed. These results are compared with a simple theory based on the saturation of the dispersion associated with the absorption. At higher intensities where the pulse approaches a 2π pulse, pulse delays (that is pulse velocities less than the velocity of light in the passive medium) are observed. View full abstract»

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  • Effect of quenching of molecular triplet states in organic dye lasers

    Page(s): 411 - 416
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    The effect of quenching of metastable triplet states upon the efficiency of organic dye lasers is considered in detail by solving the coupled differential equations describing the laser process. It is shown that specific quenching agents for excited triplet states can 1) cause a dramatic increase in the laser efficiency, 2) negate the previous requirements of very fast pumping sources, and 3) permit the use of dyes with relatively small fluorescence quantum yields. The addition of quenching agents that quench both singlet and triplet states (such as molecular oxygen) generally improves the efficiency although not as dramatically. Steady-state solutions were developed that lead to analytical expressions for the laser efficiency and the concentrations of the excited states as a function of time. View full abstract»

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  • Experimental comparison of tuned organic lasers

    Page(s): 473 - 475
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    Measurements of the tuned laser output power as a function of wavelength of solutions of seven organic fluors are presented. Tuned laser action was obtained through placing the solution in a cubic spectrosil cell situated in a cavity between a partially reflecting silvered output mirror and a diffraction grating and pumping the dye with the frequency-doubled output of a ruby or neodymiumQ-switched laser. View full abstract»

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  • Note on near-infrared operating characteristics of the mercury ion laser

    Page(s): 469 - 471
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    Additional excitation mechanisms, apparently overlooked in [1], but previously reported to be responsible for the selective excitation of the Hg II7p2P_{3/2}upper state of the 6150-Å laser line in mercury-helium lasers, are referenced and discussed. It is pointed out that asymmetric charge transfer and Penning-type ionization reactions can also account for the selective excitation of the Hg II7p2P_{3/2}state as well as direct electron impact excitation from the Hg I ground state. View full abstract»

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  • Intensity distribution for a Q-switched laser

    Page(s): 428 - 435
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    We examine the nonlinear dynamics of the turn-on of aQ-switched laser (or maser) oscillator. The description of the laser is fully quantal, including fluctuations. We use the coherent state representation for the field, and treat the atoms adiabatically. We obtain for the first time an accurate analytical solution for the distribution, which describes the probability, in an ensemble of identically prepared lasers, that the field intensity has a certain value at a certain time after the initiation of theQ-switch. The most easily observable fluctuation effect is a timing jitter in the turn-on, amounting to about two and one-half times the time constant, which describes the early exponential rise of the field intensity. An example is presented, using parameters approximating those of a 1-mW helium-neon laser. View full abstract»

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  • Laser-pulse shaping using inducible absorption with controlled Q-switch time behavior

    Page(s): 442 - 450
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    The behavior ofQ-switched laser-pulse shapes caused by various optical nonlinearities within the optical resonator is treated with an extended version of the Statz-de Mars equations. The importance ofQ-switch time behavior together with optical nonlinearity is shown by means of waveforms calculated at selected values of essential parameters, and good qualitative correspondence with a wide variety of relevant experimental observations is reported. A method of estimating some of the qualitative effects of parameter variations is described, providing an alternative to computer calculations when full details are not required. View full abstract»

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  • Dynamics of feedback-controlled Nd:YAG laser and its application for digital scan laser

    Page(s): 436 - 441
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    The dynamics of a feedback-controlled Nd:YAG laser are examined. By introducing feedback-loss control in a Nd:YAG scan laser, the undesirable transient behavior of theQ-switching operation is avoided, increasing the switching speed of the scan laser up to the megahertz range. 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