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1 Aug 1972

Volume 21, Issue 3, pp. 79-119


Momentum transfer and plasma formation above a surface with a high‐power CO2 laser

A.N. Pirri, R. Schlier, and D. Northam

Appl. Phys. Lett. 21, 79 (1972); http://dx.doi.org/10.1063/1.1654297 (3 pages) | Cited 43 times

Online Publication Date: 16 October 2003

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An experiment was performed to measure the total impulse transferred to a surface by a high‐power pulsed 10.6‐μ laser under atmospheric conditions, and also to determine the degree to which the observed plasma decouples the laser energy from the surface. Specific interest was directed toward conditions under which a ``radiation‐driven detonation wave'' may form due to the presence of a surface. The momentum transferred in dyn sec∕J decreases with an increase in the ratio of incident energy to spot area since a larger fraction of the energy is decoupled from the surface.

Vibration‐to‐vibration energy transfer in N2☒CO

Paul F. Zittel and C. Bradley Moore

Appl. Phys. Lett. 21, 81 (1972); http://dx.doi.org/10.1063/1.1654298 (3 pages) | Cited 23 times

Online Publication Date: 16 October 2003

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The rate of transfer of a vibrational quantum from N2 to CO has been measured at room temperature using a laser‐excited vibrational fluorescence technique.

New electro‐optic light valve device for image storage and processing

M. Grenot, J. Pergrale, J. Donjon, and G. Marie

Appl. Phys. Lett. 21, 83 (1972); http://dx.doi.org/10.1063/1.1654299 (3 pages) | Cited 9 times

Online Publication Date: 16 October 2003

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A new electro‐optic light valve, based on the Pockels effect in a KD2PO4 crystal addressed by photoconduction, is described. At the present stage, the picture exhibits a resolution of 20 lp∕mm (line pairs∕mm), a very uniform contrast of 40∕1, and an extensive grey scale; the writing time is less than 10 μsec. The device allows image addition and image subtraction and can be used as an input device in optical coherent processors.

Probing of acoustic shear wave radiation in surface wave devices

V.M. Ristic, M. Zuliani, G. Stegeman, and P. Vella

Appl. Phys. Lett. 21, 85 (1972); http://dx.doi.org/10.1063/1.1654300 (3 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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Simultaneous Rayleigh and shear wave generation has been achieved using interdigital transducers on a yz LiNbO3 sample at a frequency of 104 MHz. A large‐diameter laser beam of 5145‐Å wavelength and 1‐W cw power was transmitted through the sample and was modulated by two acoustic waves. The double‐modulated laser beam causes fringes at the recording plane, which were used for an accurate determination of the shear wave velocity vs and of the shear wave acoustic radiation angle α into the crystal. It was found that vs = 3.547 ×103 m∕sec for α = 14.3°. The shear wave conversion loss of the transducer was approximately 6 dB.

Optical waveguiding in proton‐implanted GaAs

E. Garmire, H. Stoll, A. Yariv, and R.G. Hunsperger

Appl. Phys. Lett. 21, 87 (1972); http://dx.doi.org/10.1063/1.1654301 (2 pages) | Cited 74 times

Online Publication Date: 16 October 2003

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We have produced optical waveguides in n‐type GaAs by implantation with 300‐keV protons. The guiding is shown to be due to the elimination of charge carriers from the implanted region. Annealing of the waveguide leads to very large reductions in the 1.15‐μ guided‐wave absorption.

New ferroelectric compound SrTeO3

Tomoaki Yamada and Hiroshi Iwasaki

Appl. Phys. Lett. 21, 89 (1972); http://dx.doi.org/10.1063/1.1654302 (2 pages) | Cited 10 times

Online Publication Date: 16 October 2003

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A synthetic compound SrTeO3 was discovered to exhibit ferroelectricity in the temperature range between 312 and 485°C. Small single crystals could be grown by the Kyropoulos method. The crystal belongs to the monoclinic system and its space group is C2/c−C2h6 at room temperature. A pronounced dielectric anomaly was observed along the b axis at 485°C. The value of the spontaneous polarization, obtained by the D‐E hysteresis loops at 50 Hz, is 3.7 μC∕cm2 at 312°C.

Differential I∕V of heterostructure correlates with laser threshold

D.L. Rode and L.R. Dawson

Appl. Phys. Lett. 21, 90 (1972); http://dx.doi.org/10.1063/1.1654303 (4 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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We report detailed measurements of current (I) vs voltage (V) on double heterojunctions (AlxGa1−xAs☒GaAs☒AlyGa1−yAs) at very high injection levels which reveal nearly discontinuous ∂2V∕∂I2 at currents ∼ 30% below lasing threshold. This behavior persists unchanged after the laser mirrors are destroyed. A similar breakpoint in ∂2V∕∂I2 is found on nonlasing double heterostructures and correlates with the onset of intense infrared emission.

Electron micrographs of hologram cross sections

Motoo Akagi, Tadao Kaneko, and Tsutomu Ishiba

Appl. Phys. Lett. 21, 93 (1972); http://dx.doi.org/10.1063/1.1654304 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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The cross sections of both amplitude and phase holograms are observed by electron microscopy. Holograms were recorded on Kodak 649F and Scientia 14C75 sheet films by using a He☒Ne laser beam (6328 Å). It is shown that the holograms are recorded throughout the whole thickness of the emulsion layer and the developed grains are enlarged by bleaching (about 1.5 times by length). This enlargement can be correlated with the thickness change of the emulsion layer during the chemical processing in making holograms.

Fabrication of single‐crystal semiconductor optical waveguides by solid‐state diffusion

H.F. Taylor, W.E. Martin, D.B. Hall, and V.N. Smiley

Appl. Phys. Lett. 21, 95 (1972); http://dx.doi.org/10.1063/1.1654305 (4 pages) | Cited 34 times

Online Publication Date: 16 October 2003

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Optical surface waveguides have been fabricated by diffusing selenium into single‐crystal CdS substrates to produce graded‐composition CdSxSe1−x crystals. Planar guides which confine a beam in one dimension and guides produced by masked diffusion capable of two‐dimensional beam confinement have been obtained. Evidence of guiding of light from a HeNe laser is provided by photographs and by measurements of spatial intensity profiles. Losses are estimated to be 10–15 dB∕cm for one‐dimensional guides and 30–40 dB∕cm for two‐dimensional guides.

Behavior of spontaneous emission across threshold in GaAs junction lasers

J.E. Ripper, Navin B. Patel, and P. Brosson

Appl. Phys. Lett. 21, 98 (1972); http://dx.doi.org/10.1063/1.1654306 (3 pages) | Cited 10 times

Online Publication Date: 16 October 2003

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The spontaneous emission behavior of a cw stripe‐geometry GaAs laser is examined in detail. Contrary to recently published results, a sharp discontinuity of the spontaneous emission growth occurs when the laser reaches threshold. Above threshold, slow increases in the spontaneous emission are observed, coming mostly from the regions where the lasing light intensity is small. Other discontinuity points were, at higher currents, observed corresponding to the onset of higher‐order modes and second‐order mode locking.

Reduction in the rate of increase of spontaneous emission from double‐heterostructure injection lasers at threshold

Thomas L. Paoli

Appl. Phys. Lett. 21, 101 (1972); http://dx.doi.org/10.1063/1.1654287 (2 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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An abrupt reduction in the rate of growth of the spontaneous emission has been observed to occur at the lasing threshold of stripe‐geometry double‐heterostructure injection lasers. The observations are contrary to a previously published result of Sommers and imply that increases in the quasi‐Fermi level separation with current are significantly reduced at the lasing threshold in agreement with present theoretical predictions.

Wavelength dependence of optimum thickness of Cs☒O low‐work‐function surfaces

H. Sonnenberg

Appl. Phys. Lett. 21, 103 (1972); http://dx.doi.org/10.1063/1.1654288 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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The amount of Cs☒O low‐work‐function surface material required to optimize the photoresponse of InAs0.4P0.6 depends upon the wavelength at which the response is to be maximized. It is shown that the optimum thickness increases exponentially with wavelength.

Additional unique property changes observed during TiNi transition

Frederick E. Wang and William J. Buehler

Appl. Phys. Lett. 21, 105 (1972); http://dx.doi.org/10.1063/1.1654289 (2 pages) | Cited 17 times

Online Publication Date: 16 October 2003

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Some unique physical property changes related with the TiNi martensitic transition, such as ``memory'' effect, have been known for some time. In this letter we report some additional observations which are of interest and are related to the TiNi transition.

Degradation of a Gunn diode by dislocations induced during thermocompression bonding

F. Hasegawa and H. Ito

Appl. Phys. Lett. 21, 107 (1972); http://dx.doi.org/10.1063/1.1654290 (2 pages) | Cited 6 times

Online Publication Date: 16 October 2003

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Many dislocations were found to be induced when GaAs chips for Gunn diodes were mounted on a heat sinking stud by a thermocompression bonding method. By introducing dislocations into epitaxial GaAs with a bending method, dislocations were confirmed to behave as acceptors in GaAs. Degradation or increase of the low field resistance of a Gunn diode by thermocompression bonding is considered to be due to induced dislocations.

Isotopic separation by photopredissociation

Edward S. Yeung and C. Bradley Moore

Appl. Phys. Lett. 21, 109 (1972); http://dx.doi.org/10.1063/1.1654291 (2 pages) | Cited 46 times

Online Publication Date: 16 October 2003

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A monochromatic source may be used to excite individual isotopic lines in a well‐resolved absorption spectrum for which the upper state is predissociated. Isotopic enrichment is thus achieved in the dissociation products, which may be stable molecules or may be chemically trapped if they are reactive. As an example, isotopic separation of hydrogen and deuterium is performed by exciting formaldehyde with a frequency‐doubled ruby laser.

Field‐ion‐microscope studies of the interface between solid‐liquid metals in vacuum

T. Utsumi and O. Nishikawa

Appl. Phys. Lett. 21, 110 (1972); http://dx.doi.org/10.1063/1.1654292 (3 pages) | Cited 5 times

Online Publication Date: 16 October 2003

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An exploratory field‐ion‐microscope study of the interface between solid and liquid metals in vacuum is reported using a Ga☒In☒Sn alloy as the liquid metal. The result with tungsten was no surface atom rearrangement at the interface; with molybdenum, the formation of an alloy of unidentified crystal structure; with iridium, no alloy formation but dissolution of a part of the tip; and with platinum, complete dissolution of the tip.

Importance of nozzle geometry to high‐pressure gas‐dynamic lasers

Donald M. Kuehn

Appl. Phys. Lett. 21, 112 (1972); http://dx.doi.org/10.1063/1.1654293 (3 pages) | Cited 4 times

Online Publication Date: 16 October 2003

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A CO2 gas‐dynamic laser (GDL) was operated over a range of reservoir pressures and temperatures, test‐gas mixtures, and nozzle geometries. A significant result is the dominant influence of nozzle geometry on laser power at high pressure. Results show that high reservoir pressure can be effectively utilized if nozzle geometry is chosen to efficiently freeze the test gas. Maximum power density with the least efficient nozzle was 3.3 W∕cm3 of optical cavity volume, whereas 83.3 W∕cm3 was attained with the most efficient nozzle.

Magnetomyography: magnetic fields around the human body produced by skeletal muscles

David Cohen and Edward Givler

Appl. Phys. Lett. 21, 114 (1972); http://dx.doi.org/10.1063/1.1654294 (3 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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Measurements of the magnetic fields from skeletal muscles, called magnetomyograms (MMG's), have been taken in a heavily shielded room with a superconducting magnetometer. These magnetic fields appear to be produced by the same currents in the volume conductor, associated with muscle action potentials, which also produce the surface electromyogram (EMG). Unlike the EMG, however, the MMG can readily detect slowly changing or direct currents. The MMG's, which were taken at locations near the elbow and the palm of the hand, are shown along with their frequency spectra.

Determination of the spatial distribution of deep centers from capacitance measurements of pn junctions

Yasuhito Zohta and Yamichi Ohmura

Appl. Phys. Lett. 21, 117 (1972); http://dx.doi.org/10.1063/1.1654295 (3 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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Effects of a spatial distribution of deep centers on the junction capacitance are reported for the first time. It is shown that the spatial distribution of deep centers can be calculated from capacitance data measured by both the capacitance‐voltage method and the Copeland method, if their energy level is known or assumed. The theory is examined with the experiment on silicon p+n junctions irradiated with 300‐kV protons. The analysis yields a value 0.40 eV below conduction band for the energy level of radiation‐induced defects, as well as a distribution of the defects with depth.
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Erratum: Increase of dislocation density in ice by dissolved hydrogen fluoride

Stephen J. Jones and Narendra K. Gilra

Appl. Phys. Lett. 21, 119 (1972); http://dx.doi.org/10.1063/1.1654296 (1 page)

Online Publication Date: 16 October 2003

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