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15 Jun 1972

Volume 20, Issue 12, pp. 469-518


Measurement of Vibration‐Vibration Energy Transfer Time in HF Gas

R.M. Osgood, A. Javan, and P. B. Sackett

Appl. Phys. Lett. 20, 469 (1972); http://dx.doi.org/10.1063/1.1654020 (4 pages) | Cited 48 times

Online Publication Date: 22 October 2003

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An experiment which yields a value of 6.6×105 Torr−1 sec−1 for the vibration‐vibration decay rate of the v=2 state in HF gas is described. The technique involves observation of the rise time of the HF v=2 vibrational fluorescence emanating from a gas sample pumped with a HF laser operating on a v=1→v=0 transition. An analytic model which predicts the temporal behavior of the HF v=1 and collisionally populated v=2 vibrational levels is also described. This model predicts an apparent decay rate of the v=2 fluorescence, which is twice that for v=1. Experimental measurements confirm this prediction.

Increased Resistance to Photodegradation of Rhodamine 6G in Cooled Solid Matrices

R. L. Fork and Z. Kaplan

Appl. Phys. Lett. 20, 472 (1972); http://dx.doi.org/10.1063/1.1654021 (3 pages) | Cited 13 times

Online Publication Date: 22 October 2003

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Improved resistance to photodegradation for Rhodamine 6G was observed when the dye was held in a cooled solid matrix of polymethylmethacrylate. The fraction of dye bleached decreased with decreasing temperature as did the rate of bleaching. The minimum detectable quantum efficiency for photodegradation was φ ≅ 10−7.

New Laser Lines in the Visible from Er3+ Ions in BaY2F8

L. F. Johnson and H. J. Guggenheim

Appl. Phys. Lett. 20, 474 (1972); http://dx.doi.org/10.1063/1.1654022 (4 pages) | Cited 37 times

Online Publication Date: 22 October 2003

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Coherent emission at 5540, 5617, and 7037 Å from Er3+ ions in BaY2F8 is reported. Oscillation at 5540 Å takes place at 77°K in a transition from 4S3∕2 to a level of the 4I15∕2 ground state at 406 cm−1. The line at 5617 Å is produced in a transition from 2H9∕2 to a level of 4I13∕2 at 6740 cm−1, and 7037 Å is generated in a transition from 2H9∕2 to a 4I11∕2 level at 10 336 cm−1. Pumping of the 4I13∕2 state results in Q switching of the output at 5540 Å. The conditions required to produce oscillation in these lines and the detrimental effects of Yb3+ are discussed.

Study of Film Thickness in rf Sputtering

H. Ratinen

Appl. Phys. Lett. 20, 477 (1972); http://dx.doi.org/10.1063/1.1654023 (2 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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The thickness of copper films prepared by the rf‐sputtering technique has been studied by changing the argon gas pressure and the distance between the target and the substrate. Glass disks with 110‐mm diameters were used as substrates. The relative thickness of a film was tested by using a laser beam. The distribution of copper was observed to be centralized as the argon gas pressure was lowered or the distance between the target and the substrate shortened. By using a proper arrangement, the film obtained was smooth enough for optical purposes.

New Output Coupling Scheme for cw Dye Lasers

Jagdeep Shah

Appl. Phys. Lett. 20, 479 (1972); http://dx.doi.org/10.1063/1.1654024 (2 pages) | Cited 4 times

Online Publication Date: 22 October 2003

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We have devised a simple new scheme of extracting tunable output from a cw dye laser. This scheme reduces the intensity of the background fluorescence of the dye to less than 10−7 of the laser intensity within 10 Å of the laser line and gives an output beam whose direction is independent of the dye laser wavelength. This scheme uses no external dispersing elements and permits a continuous recording of the data as a function of dye laser wavelength.

Suppression of Spurious Triple‐Transit Signals in Acoustic Surface‐Wave Delay Lines

M. T. Wauk

Appl. Phys. Lett. 20, 481 (1972); http://dx.doi.org/10.1063/1.1654025 (3 pages) | Cited 1 time

Online Publication Date: 22 October 2003

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Spurious triple‐transit signals can be rejected through phase cancellation by rotation of one transducer with respect to the other or by use of a triangular‐shaped metal film in the path between parallel transducers. Rejection is facilitated by slightly limiting the aperture via mechanical surface loading. The technique is demonstrated to give high triple‐transit suppression in delay lines with 20‐electrode‐pair transducers that give specular acoustic reflections. The technique is not found to be useful for conjugate‐matched 5‐electrode‐pair transducers, which are shown to give acoustic reflections normal to the electrodes.

Structure of a Coincidence and Near‐Coincidence Tilt Boundary in Gold

P. Chaudhari and S. Mader

Appl. Phys. Lett. 20, 483 (1972); http://dx.doi.org/10.1063/1.1654026 (3 pages) | Cited 1 time

Online Publication Date: 22 October 2003

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The structure of tilt grain boundaries formed by a rotation of 60° and 30° about a 〈111〉 axis has been examined by transmission electron microscopy. In specimens containing 30° boundaries, low‐angle dislocation arrays with a tilt angle of 2.2° are commonly observed. This is attributed to the presence of a coincidence site lattice relation at 27.8°.

Absorption at 10.6 μ via Ionic Dipole‐Dipole Interactions

V.O. Nicolai

Appl. Phys. Lett. 20, 486 (1972); http://dx.doi.org/10.1063/1.1654027 (2 pages) | Cited 1 time

Online Publication Date: 22 October 2003

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A theory is suggested to explain absorption at 10.6 μ in crystals via ionic dipole‐dipole interactions. The theory indicates that minimal absorption is obtained with crystals which have symmetry with respect to optical modes and with preferred orientations of the crystals.

Vibrational Relaxation Measurements Using ``Transient'' Stimulated Raman Scattering

M. A. Kovacs and M. E. Mack

Appl. Phys. Lett. 20, 487 (1972); http://dx.doi.org/10.1063/1.1654028 (4 pages) | Cited 56 times

Online Publication Date: 22 October 2003

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Vibrational relaxation measurements in several gases have been made, subsequent to vibrational pumping by picosecond pulse‐generated ``transient'' stimulated Raman scattering. This technique permits relaxation measurements at room temperature or below in a number of gases for which previously no such measurement was possible.

Holography and Holographic Interferometry with Pulsed High‐Power Infrared Lasers

G. Decker, H. Herold, and H. Röhr

Appl. Phys. Lett. 20, 490 (1972); http://dx.doi.org/10.1063/1.1654029 (3 pages) | Cited 20 times

Online Publication Date: 22 October 2003

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Holograms are produced on bismuth and paraffin films with pulsed TEA CO2 laser light. Sensitivity of both films is about 0.3 J∕cm2. Local resolution proved to be much better than 70 lines∕mm. Capability of this holographic technique for interferometric measurements is demonstrated.

New Magnetic Material Having Ultrahigh Magnetic Moment

T. K. Kim and M. Takahashi

Appl. Phys. Lett. 20, 492 (1972); http://dx.doi.org/10.1063/1.1654030 (3 pages) | Cited 230 times

Online Publication Date: 22 October 2003

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The change of the saturation magnetization of Fe films with the pressure of nitrogen during deposition ranging from 2 × 10−5 to 7 × 10−3 Torr has been investigated systematically. We found a new magnetic material which has the highest saturation magnetization at room temperature, 2050 G, among those of all the magnetic materials. This was attributed to Fe16N2, which has a bct structure, and the magnetic moment associated with Fe atoms of Fe16N2 was deduced to be 3.0 μB.

Ionization Instability in Atmospheric‐Pressure Gas Discharges

T. W. Johns and J. A. Nation

Appl. Phys. Lett. 20, 495 (1972); http://dx.doi.org/10.1063/1.1654031 (2 pages) | Cited 16 times

Online Publication Date: 22 October 2003

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A photographic and oscillographic study of discharges in helium‐carbon‐dioxide mixtures at atmospheric pressure has shown that fine filaments develop in the discharge column. The origin of these nonuniform discharge paths is discussed, and a means for maximizing the energy input to the plasma prior to filamentation is presented. This process is of relevance to the design of TEA lasers.

High‐Pressure Pulsed CO2 Chemical Transfer Laser

T. O. Poehler, M. Shandor, and R. E. Walker

Appl. Phys. Lett. 20, 497 (1972); http://dx.doi.org/10.1063/1.1654032 (3 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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The exothermic chain reactions between deuterium and fluorine have been used to produce intense laser emission from carbon dioxide in a high‐pressure pulsed transfer laser. Stable mixtures of D2☒F2☒CO2 diluted in He and cooled to −60°C were used as a fuel. Reactions initiated by flash photolysis of this system produced 10.6‐μm radiation with peak power of 200 kW and total energy of 5 J in dilute mixtures at total pressures up to 1 atm. The output power, laser pulse duration, and time of maximum gain are found to be strongly dependent on partial pressures of the constituents, total pressure of reactive components, nature of the diluents, and degree of refrigeration of the mixture.

Tunable GaAs Laser in an External Dispersive Cavity

R. Ludeke and E. P. Harris

Appl. Phys. Lett. 20, 499 (1972); http://dx.doi.org/10.1063/1.1654033 (2 pages) | Cited 29 times

Online Publication Date: 22 October 2003

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Tunability of the cw radiation from a GaAs injection laser in an external dispersive cavity was achieved over a range of 150 Å about a center wavelength of 8525 Å at 77°K. The emitted radiation was analyzed with a Fabry‐Perot etalon. Under certain conditions single‐mode operation with cw output power as large as 17 mW was observed. Half‐width of such modes was estimated to be less than 350 MHz.

cw Laser Action on 31 Transitions in Tellurium Vapor

W. T. Silfvast and M. B. Klein

Appl. Phys. Lett. 20, 501 (1972); http://dx.doi.org/10.1063/1.1654034 (4 pages) | Cited 8 times

Online Publication Date: 22 October 2003

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We have observed 31 cw laser transitions in the spectrum of singly ionized Te II, ranging in wavelength from 4843 to 9378 Å. 16 transitions were observed with He as a buffer gas, and 20 transitions were observed with Ne (5 were common to both gases). The experimental evidence indicates that charge transfer is the dominant excitation mechanism for both gases.

Information Storage Using Inhibited Cathodoluminescence

H. E. Bishop, R. P. Henderson, P. Iredale, and D. Pooley

Appl. Phys. Lett. 20, 504 (1972); http://dx.doi.org/10.1063/1.1654035 (3 pages) | Cited 5 times

Online Publication Date: 22 October 2003

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It has been shown that reversible information storage in crystals can be achieved using the inhibition of cathodoluminescence by defects produced by electron irradiation. Since an electron beam of constant energy is used to access the store and to execute the binary operations of write, erase, and read, the addressing problems are minimized. The writing and erasing times are on the order of a few microseconds, and the reading time can be a few hundred nanoseconds.

Laser‐Induced Refractive‐Index Change in As☒S☒Ge Glasses

Yoshiro Ohmachi and Takeo Igo

Appl. Phys. Lett. 20, 506 (1972); http://dx.doi.org/10.1063/1.1654036 (3 pages) | Cited 38 times

Online Publication Date: 22 October 2003

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Effect of light irradiation on evaporated chalcogenide glass films of an As☒S☒Ge system has been studied. In order to make quantitative measurements of refractive‐index change resulting from light irradiation, light diffraction efficiency from the phase grating produced in the films with the technique of holographic storage has been measured. The maximum refractive‐index change of 0.056 has been obtained in an As2S3 film. This value is two orders of magnitude higher than that of Fe‐doped LiNbO3 single crystals. Light irradiation onto the films is considered to have two competing effects, one being thermal and the other purely optical.

CO2 Waveguide Gas Laser

Richard E. Jensen and Mary S. Tobin

Appl. Phys. Lett. 20, 508 (1972); http://dx.doi.org/10.1063/1.1654037 (3 pages) | Cited 23 times

Online Publication Date: 22 October 2003

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The characteristics of a CO2 waveguide gas laser are described. An output power of 2.5 W was obtained from a discharge tube having a 23.7‐cm length and a 3.3‐mm diameter. The output mode pattern was very stable and insensitive to disturbances of the resonator and indicates the laser output is predominantly the EH11 waveguide mode. The power output was sensitive to mirror position, and maximum power was obtained when the centers of curvature of the mirrors were a few centimeters inside the waveguide.

Nonlinear Forward Drift of Electrons in a Laser Beam

O. S. Lieu and E. E. H. Shin

Appl. Phys. Lett. 20, 511 (1972); http://dx.doi.org/10.1063/1.1654038 (2 pages) | Cited 1 time

Online Publication Date: 22 October 2003

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Electrons interacting with laser radiation acquire a nonlinear drift velocity vD = e2E02/2m2cω2 in the forward longitudinal direction, thus giving rise to a dc current. Although its magnitude is too small to contribute to the ``heating'' of electrons, it may nevertheless prove useful in a laser‐operated solid‐state device using a low‐effective‐mass semiconductor.

Significance of Electric Fields on the Growth of Thin Metal Films

L. E. Murr and H. P. Singh

Appl. Phys. Lett. 20, 512 (1972); http://dx.doi.org/10.1063/1.1654039 (3 pages) | Cited 7 times

Online Publication Date: 22 October 2003

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Thin films of Au, Ag, Pt, Pd, In, Sn, Bi, and Te were vacuum vapor deposited onto air‐cleaved NaCl (001) substrates in the absence of an electric field and in the presence of dc fields (in the plane of the substrate), ranging in intensity from 10 to 103 V∕cm. The vacuum environments were varied between 10−6 and 10−9 Torr, and evaporation rates ranged from 10 to 103 Å∕sec. Substrate temperatures were varied from 25 to 350°C for a distribution of mean film thicknesses ranging from 15 to 1200 Å. No significant effects of an electric field applied in the plane of the substrate were observed upon examination and comparison of representative film samples by transmission and scanning electron microscopy.

p‐Channel Charge‐Coupled Devices with Resistive Gate Structure

Choong‐Ki Kim and E. H. Snow

Appl. Phys. Lett. 20, 514 (1972); http://dx.doi.org/10.1063/1.1654040 (3 pages) | Cited 2 times

Online Publication Date: 22 October 2003

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Charge‐coupled devices with resistive material covering the oxide between adjacent gate electrodes are described. These devices were fabricated incorporating a continuous strip of deposited silicon with doped and undoped regions. Since the surface potential under the gap can be controlled using this structure, reliable p‐channel devices with nonoverlapping gate electrodes can be made which have all the advantages of p‐channel silicon gate technology. Transfer efficiencies greater than 99.3% per transfer have been obtained at up to 1‐MHz bit rates for three‐phase experimental devices.

Interference Effects in Laser‐Modulated Electron Beams

Robert W. Schmieder

Appl. Phys. Lett. 20, 516 (1972); http://dx.doi.org/10.1063/1.1654041 (3 pages)

Online Publication Date: 22 October 2003

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A new class of electron interferometers is proposed that make use of a laser‐modulated electron beam. The observable interference arises in second‐order processes, since the first‐order interference oscillates rapidly and averages to zero. It is shown that the detected signal varies sinusoidally with the separation of two sequential modulators, thus generating a fringe pattern with peak‐to‐peak spacing that may be smaller or larger than the laser wavelength. It is suggested that such devices could be used to detect and study the modulation process and, because they operate with massive charged particles, to perform a wide variety of new experiments and high‐precision measurements.
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