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1 Dec 1973

Volume 23, Issue 11, pp. 581-648


Electronically focused acoustic imaging device

J. F. Havlice, G. S. Kino, and C. F. Quate

Appl. Phys. Lett. 23, 581 (1973); http://dx.doi.org/10.1063/1.1654755 (3 pages) | Cited 3 times

Online Publication Date: 9 October 2003

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A new type of acoustic imaging device, which scans a large array of piezoelectric detectors is described. Scanning is carried out by a signal traveling along an acoustic surface wave delay line. The device can be electronically focused, and has given images of objects 20 cm from the detector array, illuminated with a 5‐MHz acoustic wave, with a definition of 1 mm.

Lithium niobate stress gauge for pulsed radiation deposition studies

R. A. Graham and R. D. Jacobson

Appl. Phys. Lett. 23, 584 (1973); http://dx.doi.org/10.1063/1.1654756 (3 pages) | Cited 11 times

Online Publication Date: 9 October 2003

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The piezoelectric response of impact‐loaded z‐cut lithium niobate is investigated to determine whether the material can be used as a time‐resolving nanosecond‐resolution stress gauge. The material is found to have appropriate properties for stresses up to 15 kbar. A gauge from this material should prove particularly useful for measurements of stress pulses resulting from the absorption of pulsed radiation in solids.

Effect of crystal structure on diffusion broadening of Mössbauer line shape in polycrystalline samples

M. Celia Dibar‐Ure and Paul A. Flinn

Appl. Phys. Lett. 23, 587 (1973); http://dx.doi.org/10.1063/1.1654757 (3 pages) | Cited 19 times

Online Publication Date: 9 October 2003

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Experimental observations of diffusional broadening of the Mössbauer resonance in polycrystalline solids have generally been analyzed on the basis of a liquidlike model which neglects the restriction of atomic jumps to crystallographically determined directions. A calculation based on the theoretical results of Chudley and Elliot for single crystals, averaged over all directions, shows that a substantial correction to the liquidlike result is required. Application of this correction, along with a simple assumption about the correlation factor largely eliminates the existing discrepancies between theory and experiment.

Electronic control of the velocity and attenuation of surface acoustic waves in piezoelectric semiconductors

A. K. Ganguly and G. Chao

Appl. Phys. Lett. 23, 590 (1973); http://dx.doi.org/10.1063/1.1654758 (3 pages)

Online Publication Date: 9 October 2003

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The velocity and attenuation of a surface acoustic wave on a piezoelectric semiconductor may be controlled by adjusting the bias of a reverse‐biased distributed diode. With the proper choice of resistivity and operating frequency, changes in velocity of 1% and attenuation of 300 dB∕cm may be achieved in c‐axis cadmium sulfide for bias voltages under 30 V. Theoretical behavior is presented and initial experimental results are summarized.

Depth distribution of implanted helium and other low‐z elements in metal films using proton backscattering

Robert S. Blewer

Appl. Phys. Lett. 23, 593 (1973); http://dx.doi.org/10.1063/1.1654759 (3 pages) | Cited 17 times

Online Publication Date: 9 October 2003

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The depth profiles of helium implanted into copper foils have been observed experimentally by a proton backscattering technique. Carbon and oxygen on the front and rear surfaces of the foils have also been resolved. The mean depth of the helium implanted at 50, 100, and 150 keV is in agreement with projected range calculations, though the rms spread in the distributions is smaller than predicted. The shape of the profiles is the Gaussian form expected from single energy implants with no evidence of tails extending deep into the foils. Detection sensitivity is greater than 1 at.% for He in Cu under the experimental conditions investigated. The mean depth (peak) of the implanted helium distributions can be determined to within ± 100 Å.

High‐sensitivity thin‐film strain sensor

Frederick J. Jeffers

Appl. Phys. Lett. 23, 596 (1973); http://dx.doi.org/10.1063/1.1654760 (2 pages)

Online Publication Date: 9 October 2003

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Evaporated cadmium sulfide thin‐film resistors have been fabricated which exhibit remarkable strain sensitivity. Electrodes are arranged in sandwich fashion so that electrons flow perpendicular to the plane of the CdS layer. The layers are doped and heat treated so that nominal unstrained resistivities are of the order of 3 × 105 Ω cm. Tensile and compressive strain in the plane of the film causes the resistance to increase and decrease, respectively, by as much as a factor of 15.

Laser mirror damage in germanium at 10.6 μm

D. C. Emmony, R. P. Howson, and L. J. Willis

Appl. Phys. Lett. 23, 598 (1973); http://dx.doi.org/10.1063/1.1654761 (3 pages) | Cited 124 times

Online Publication Date: 9 October 2003

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Damage in the germanium output mirror of a TEA CO2 laser shows a periodicity of 10.6 μm, the laser wavelength. A mechanism is proposed in which scattered and cavity radiation interfere. An interference mechanism is confirmed by experiments outside of the laser cavity. Periodic damage is obtained in thin films irradiated at angles other than the normal where the fringe spacing is modified.

CO2 laser beam refraction in a linear discharge plasma

G. M. Molen, M. Kristiansen, and M. O. Hagler

Appl. Phys. Lett. 23, 601 (1973); http://dx.doi.org/10.1063/1.1654762 (3 pages) | Cited 10 times

Online Publication Date: 9 October 2003

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Beam guiding and focusing have been observed for CO2 laser propagation in a high‐density low‐temperature annular plasma. A TEA laser was fired along the axis of a cylindrical plasma column of densities in the 1016–1017‐cm−3 range. Several radial density profiles were investigated. Beam guiding and focusing were observed when the density had a minimum on the axis. A density maximum on‐axis refracted the beam toward the tube walls, and intense ``hot spots'' resulting from apparent filamentation inside the plasma were recorded.

Effects of lattice disorder on the intrinsic optical damage fields of solids

D. W. Fradin and Michael Bass

Appl. Phys. Lett. 23, 604 (1973); http://dx.doi.org/10.1063/1.1654763 (3 pages)

Online Publication Date: 9 October 2003

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Measurements of the effects of polycrystallinity and lattice disorder on the intrinsic laser‐induced damage fields of transparent solids are reported. Extreme lattice disorder such as present in a highly amorphous material such as fused quartz causes the damage field to increase, whereas less severe disorder does not measurably affect the breakdown strength. This is consistent with an electron avalanche intrinsic damage mechanism.

Role of coating defects in laser‐induced damage to dielectric thin films

L. G. DeShazer, B. E. Newnam, and K. M. Leung

Appl. Phys. Lett. 23, 607 (1973); http://dx.doi.org/10.1063/1.1654764 (3 pages) | Cited 10 times

Online Publication Date: 9 October 2003

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The laser‐induced damage thresholds of two different dielectric thin‐film coatings increased with decreasing spot size and were invariant for spot sizes greater than 150 μm. A simple model has been suggested that the distribution and nature of coating defects have played an important role in this spot‐size dependence, e.g., the probability of the laser beam striking a defect site will be greater for larger spot sizes and that damage in materials can be distinguished as defect damage and intrinsic damage.

Dynamic stabilization and parametric excitation of instabilities in liquid‐gas interfaces with nonharmonic oscillations

Friedrich M. Hoffmann and Gerd H. Wolf

Appl. Phys. Lett. 23, 610 (1973); http://dx.doi.org/10.1063/1.1654765 (2 pages) | Cited 1 time

Online Publication Date: 9 October 2003

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Experiments on the dynamic stabilization of the Rayleigh‐Taylor instability are described, where the applied oscillations are modulated in their frequency or chosen to be strongly anharmonic. While, compared to the application of harmonic oscillations, an expected rise of the excitation threshold of parametric instabilities could be observed, a corresponding shift of the boundary discriminating against the slowest Rayleigh‐Taylor mode did not allow to obtain a measurable increase of the over‐all stability region.

Optical isolation using a Doppler‐broadened molecular absorber

F. Keilmann, R. L. Sheffield, M. S. Feld, and A. Javan

Appl. Phys. Lett. 23, 612 (1973); http://dx.doi.org/10.1063/1.1654766 (3 pages) | Cited 1 time

Online Publication Date: 9 October 2003

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A new principle for optical isolation based on the saturation of a Doppler‐broadened resonance is described. It depends on an initial difference in the power levels of the incident and reflected waves. The technique is demonstrated using an SF6 absorber to isolate the P(18) line of the CO2 transition at 10.57 μm.

Compensation from implantation in GaAs

D. Eirug Davies, J. K. Kennedy, and A. C. Yang

Appl. Phys. Lett. 23, 615 (1973); http://dx.doi.org/10.1063/1.1654767 (2 pages) | Cited 14 times

Online Publication Date: 9 October 2003

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Non‐dopant ions have been implanted at low doses ([inverted lazy s] 1010 cm−2) into GaAs to determine the extent of carrier removal and to pin‐point annealing stages for carrier recovery. A removal rate of around 200 carriers per ion is found for such lighter ions as B+, N+, and F+. At the 1‐MeV energy used, compensating damage extends along the ion track right from the GaAs wafer surface. Partial recovery of the carriers as well as mobility occurs at the well‐known 225 °C electron damage annealing stage. A further annealing stage is found at [inverted lazy s] 525 °C.

Photodetection by barrier modulation in Cu‐diffused Au∕CdS junctions

H. K. Bücher, B. C. Burkey, G. Lubberts, and E. L. Wolf

Appl. Phys. Lett. 23, 617 (1973); http://dx.doi.org/10.1063/1.1654768 (3 pages) | Cited 7 times

Online Publication Date: 9 October 2003

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Modulation of essentially thermionic forward current by light‐induced lowering of an electrostatic barrier leads to steady‐state electron per photon gain of order 106 in narrow Cu‐compensated Au∕CdS junctions. The light dependence of the barrier, whose peak lies within the semiconductor, is measured directly by internal photoemission. A model of the junction is presented and the limiting threshold and gain of this type of device is estimated.

Single heterojunction Pb1−x Snx Te diode lasers

J. N. Walpole, A. R. Calawa, R. W. Ralston, T. C. Harman, and J. P. McVittie

Appl. Phys. Lett. 23, 620 (1973); http://dx.doi.org/10.1063/1.1654769 (3 pages) | Cited 22 times

Online Publication Date: 9 October 2003

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Single heterojunction diode lasers in the Pb1−xSnx Te alloy system have been fabricated by low‐temperature vacuum deposition of n‐PbTe on a p‐Pb0.88Sn0.12 Te substrate. The lasers have lower threshold current densities and operate cw at higher temperatures than homojunction devices in this material. At laser threshold the incremental diode resistance drops abruptly from 0.5 Ω to a series resistance limited value of 0.08 Ω, a previously unobserved effect in diode lasers which indicates very high internal quantum efficiency.

Analysis of a collisionally induced dipole laser

Walter H. Christiansen and E. Greenfield

Appl. Phys. Lett. 23, 623 (1973); http://dx.doi.org/10.1063/1.1654770 (3 pages) | Cited 2 times

Online Publication Date: 9 October 2003

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An electric dipole moment is induced in homonuclear molecules during collisions, allowing radiative transitions which are otherwise forbidden. This effect, coupled with high‐pressure electrical excitation, may be used to achieve laser action in a homonuclear gas. Properties of this type laser include a very broad gain bandwidth and a new type of partial inversion. A mixture of H2 and Xe is analyzed as a prospective system wherein efficiencies of about 20% are predicted for picosecond pulses at 2.8 μm.

Efficient low‐band operation of a CO chemical laser

W. Q. Jeffers and C. E. Wiswall

Appl. Phys. Lett. 23, 626 (1973); http://dx.doi.org/10.1063/1.1654771 (2 pages) | Cited 7 times

Online Publication Date: 9 October 2003

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A cw O∕CS2 CO chemical laser has been operated at a chemical efficiency of 37.5%. This result was achieved by the use of N2O as a diluent whose V‐V transfer effects on the chemically formed CO are such as to strongly enhance emission in the low vibrational bands. The free‐running oscillator spectra start at v = 12 → 11 and continue to v = 2 → 1, with more than 50% of the output in the low bands 6 → 5 to 2 → 1. These results again emphasize the importance of vibrational energy transfer in chemical laser media.

Periodic breakup of optical beams due to self‐focusing

A. J. Campillo, S. L. Shapiro, and B. R. Suydam

Appl. Phys. Lett. 23, 628 (1973); http://dx.doi.org/10.1063/1.1654772 (3 pages) | Cited 94 times

Online Publication Date: 9 October 2003

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Transverse spatial periodic breakup of an optical beam due to self‐focusing has been experimentally observed. Each focal spot evolves from a zone with well‐defined dimensions. The formation from these zones is consistent with an instability theory. Calculated and experimentally observed zone dimensions and powers are in good quantitative agreement.

Pulsed high‐power HF laser holography with gelatine detectors

W. Braun, G. Decker, and H. Röhr

Appl. Phys. Lett. 23, 631 (1973); http://dx.doi.org/10.1063/1.1654773 (2 pages) | Cited 3 times

Online Publication Date: 9 October 2003

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Holographic interferograms are produced on gelatine films with pulsed HF laser light (λ ≈ 3 μm). The sensitivity is about 2 J∕cm2, and the resolution at least 300 lines∕mm. The spectrum of the HF laser is measured by means of holography.

Acoustic amplifier for detection of atmospheric pollutants

C. F. Dewey, R. D. Kamm, and C. E. Hackett

Appl. Phys. Lett. 23, 633 (1973); http://dx.doi.org/10.1063/1.1654774 (3 pages) | Cited 55 times

Online Publication Date: 9 October 2003

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Kreuzer has demonstrated the feasibility of detecting atmospheric pollutants using acoustic signals produced by volumetric absorption of infrared radiation. We have investigated a substantial improvement of this technique wherein the optical excitation beam is modulated at a frequency corresponding to a natural acoustic resonance of the sample chamber. Acoustic amplification factors exceeding 100 have been observed.

Electrical effect of growth striations in the silicon vidicon‐type camera tubes

Shigeo Yoshikawa and Jun‐ichi Chikawa

Appl. Phys. Lett. 23, 636 (1973); http://dx.doi.org/10.1063/1.1654775 (3 pages) | Cited 3 times

Online Publication Date: 9 October 2003

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Camera tubes with a CdTe☒Si heterojunction target have been fabricated to observe the electrical effects of the growth striations in dislocation‐free Si crystals grown by the floating‐zone technique. Their video images under a uniform illumination showed spiral patterns due to the growth striations. The origin of the patterns is attributed to the electric fields which are formed locally in the growth striations and drive the photoinduced holes toward the growth direction.

Detection and generation of magnetic bubble domains using ferrimagnetic resonance

Horst Dötsch, Hans Jürgen Schmitt, and Jürgen Müller

Appl. Phys. Lett. 23, 639 (1973); http://dx.doi.org/10.1063/1.1654776 (3 pages) | Cited 16 times

Online Publication Date: 9 October 2003

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Ferrimagnetic resonance within the bubble layer is used to couple two microwave transmission lines. If a bubble is switched into the coupling region which is comparable in size with a bubble domain, the transmitted microwave signal changes. For a 5‐μm bubble a Zero∕One ratio of 6:1 has been obtained. It is also possible to influence the resonance transmission in a reference layer adjacent to the bubble layer by the magnetic stray field of a bubble. At high power levels a nonlinear interaction between the microwaves and the magnetic domains is observed which can be used for bubble generation.

High‐field magnetization and coercivity of amorphous rare‐earth‐Fe2 alloys

Arthur E. Clark

Appl. Phys. Lett. 23, 642 (1973); http://dx.doi.org/10.1063/1.1654777 (3 pages) | Cited 64 times

Online Publication Date: 9 October 2003

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High‐field magnetization studies were made from 4 °K to room temperature on rapidly sputtered TbFe2, DyFe2, and SmFe2. At 4.2 °K the magnetic moment resembles that of polycrystal samples, whereas at room temperature it is substantially lower. Huge coercive forces (20–30 kOe) were observed at 4.2 °K. Partial crystallization of TbFe2 from the sputtered amorphous state yields high‐energy products and coercivities (> 3 kOe) at room temperature.

Source materials for ion implantation

A. Axmann

Appl. Phys. Lett. 23, 645 (1973); http://dx.doi.org/10.1063/1.1654778 (4 pages) | Cited 7 times

Online Publication Date: 9 October 2003

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A survey is given of source materials which can be used to draw ion currents from a Nielsen source. More than 50 different ion species are listed including Pd+, Ir+, Pt+, and Au+. Actual currents obtained during implantation are also reported.
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