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15 Sep 1972

Volume 21, Issue 6, pp. 247-298


Arc‐excited flowing CO chemical laser

Laurence R. Boedeker, John A. Shirley, and Barry R. Bronfin

Appl. Phys. Lett. 21, 247 (1972); http://dx.doi.org/10.1063/1.1654363 (3 pages) | Cited 8 times

Online Publication Date: 16 October 2003

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Application of thermal dissociation of O2, developed within arc‐heated gas mixtures, followed by a sufficiently rapid convection to preserve O atom concentrations and subsequent CS2 injection, has generated efficiently a CO laser medium. In preliminary experiments, this pumping technique has produced a 34‐W cw laser emitting over a band of vibration‐rotation transitions from 4.9 to 5.7 μ from a 5‐cm active transverse optical cavity.

Secondary electron emission from GaAs

W.A. Gutierrez, H.D. Pommerrenig, and S.L. Holt

Appl. Phys. Lett. 21, 249 (1972); http://dx.doi.org/10.1063/1.1654364 (2 pages) | Cited 10 times

Online Publication Date: 16 October 2003

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Secondary emission measurements have been made on thick and thin epitaxially grown p‐doped GaAs. Reflection mode gains of 400 at primary voltages of 20 kV have been observed for unthinned layers. The variation of gain with white‐light photoresponse has also been measured. For 5‐μ‐thick self‐supporting layers, a gain of 115 and 30 (at 10 kV primary voltage) has been measured for the reflection and transmission modes, respectively. The escape depth is estimated to be 2 μ with an escape probability of 0.14.

Photocapacitance studies of deep‐double‐electron‐trap oxygen in gallium phosphide

H. Kukimoto, C.H. Henry, and G.L. Miller

Appl. Phys. Lett. 21, 251 (1972); http://dx.doi.org/10.1063/1.1654365 (3 pages) | Cited 22 times

Online Publication Date: 16 October 2003

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Transitions of the deep O donor in a GaP p‐n junction are studied by photocapacitance. It is found that the O donor may deeply trap either one or two electrons. The four optical absorption cross sections are measured for the two states, and from this information the O concentration profile is determined. The concentration ranges from (4 ± 1) × 1014 cm−3 on the n side to (1.5 ± 0.2) × 1016 cm−3 on the p side of the junction depletion layer. It is believed that these measurements represent the first direct determination of the concentration of O donors in GaP.

Interaction of laser light with magnetic domains

A. Ashkin and J.M. Dziedzic

Appl. Phys. Lett. 21, 253 (1972); http://dx.doi.org/10.1063/1.1654366 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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Laser beams, when partially absorbed in epitaxial (Er2Eu1Ga0.7Fe4.3O12) magnetic garnet films, are used to thermally manipulate bubble and strip magnetic domains. Bubbles and strips can be created or annihilated, as well as captured and moved about freely by the light spot, without the use of magnetic circuits. Bubbles can be arranged in fixed arrays or propagated at high speeds. A novel form of reversible strip domain writing is demonstrated.

Platinum silicide‐aluminum Schottky diode characteristics

H.H. Hosack

Appl. Phys. Lett. 21, 256 (1972); http://dx.doi.org/10.1063/1.1654367 (2 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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The effects of heat treatment on platinum silicide Schottky diodes with aluminum metal contacts have been investigated. It has been found that the aluminum reacts with the silicide causing a change in the effective metal‐semiconductor barrier height over a range of approximately 0.25 eV. Schottky diodes with initial platinum silicide characteristics convert to devices with barrier heights characteristic of aluminum after extended heat treatments.

Efficiency shift in very high efficiency GaP (Zn☒O) diodes

R. Solomon and D. DeFevere

Appl. Phys. Lett. 21, 257 (1972); http://dx.doi.org/10.1063/1.1654368 (4 pages) | Cited 8 times

Online Publication Date: 16 October 2003

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High‐efficiency GaP (Zn☒O) diodes have been observed, in some instances, to show a substantial and permanent increase in efficiency when subjected to a large forward bias. Experiments suggest that the effect is related to precipitation in the n and p layers. A model is presented which is able to account for most of the observations.

Relative importance of electrostriction and the Kerr effect to self‐focusing in optical glasses

Albert Feldman, Deane Horowitz, and Roy M. Waxler

Appl. Phys. Lett. 21, 260 (1972); http://dx.doi.org/10.1063/1.1654369 (3 pages) | Cited 1 time

Online Publication Date: 16 October 2003

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The damage threshold for three optical glasses was found to be higher for circularly polarized radiation than for linear polarization, using 26‐nsec pulses from a Nd:glass laser. The damage was assumed to result from self‐focusing. The fractional contribution of electrostriction to the total nonlinear index n2 is estimated to be 0.8 ± 0.2 for borosilicate crown glass, 1.15 ± 0.35 for fused silica, and 0.4 ± 0.1 for dense flint glass, assuming the Kerr effect to be the only other self‐focusing mechanism. The data are consistent with present concepts of glass structure. The high damage threshold in fused silica is attributed to its relatively small Kerr effect.

Magnetostatic potential wells and drive fields in field access bubble domain drive circuits

P.K. George and T.T. Chen

Appl. Phys. Lett. 21, 263 (1972); http://dx.doi.org/10.1063/1.1654370 (2 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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A technique for experimentally measuring the z‐component fields produced by Permalloy drive circuits in the presence of both bubble and external in‐plane drive fields is proposed. Experimental results based upon this technique are presented for a simple bar, a Y‐bar propagation pattern and a chevron propagation pattern. The implications of these results with respect to device operation and design are discussed.

Single‐frequency traveling‐wave Nd:YAG laser

A.R. Clobes and M.J. Brienza

Appl. Phys. Lett. 21, 265 (1972); http://dx.doi.org/10.1063/1.1654371 (3 pages) | Cited 13 times

Online Publication Date: 16 October 2003

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Single‐frequency operation of a cw pumped Nd:YAG laser was achieved by using a ring cavity configuration containing a small differential loss. The resulting unidirectional traveling wave eliminated spatial hole burning, and the output of the laser was at a single frequency.

R‐branch emission from a cw CO chemical laser

W.Q. Jeffers

Appl. Phys. Lett. 21, 267 (1972); http://dx.doi.org/10.1063/1.1654372 (3 pages) | Cited 7 times

Online Publication Date: 16 October 2003

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The effect of adding vibrationally ``cold'' CO to a CO chemical laser is shown to increase the inversion ratios on the vibration levels of the chemically formed molecules. This fact is demonstrated experimentally by the observation of R‐branch emission, reported here for the first time in any cw flow and mixing chemical laser. R‐branch lines can be seen experimentally only with the addition of cold CO, and then only with a frequency‐selective optical cavity. Theoretical calculations indicate that the total inversions predicted from the known distribution of the O + CS pumping reaction are rapidly depleted by vibration‐vibration (VV) relaxation. The collisional VV exchanges with cold CO are shown to increase the vibrational inversion ratios to the extent that total inversion is observable in experimental devices limited by mixing and reaction times that are not fast compared with VV equilibration.

Secondary hydrodynamic structure in dynamic scattering

Alan Sussman

Appl. Phys. Lett. 21, 269 (1972); http://dx.doi.org/10.1063/1.1654373 (4 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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A hydrodynamic regime in dynamic scattering has been observed in which the relaxation time depends on the voltage at turnoff. This regime manifests itself, above a threshold voltage, with microscopic regions of increased on‐axis optical density which grow until the whole cell area is converted. It has been found in all nematic materials which exhibit dynamic scattering. With originally perpendicular homeotropic orientation, the speed of relaxation increases with the square of the voltage at turnoff. With originally parallel homeotropic orientation, the speed of relaxation decreases with increasing voltage at turnoff. The time t to fill a given area depends on the current density and the voltage above a second threshold Vm, according to the empirical relation J(V ‐ Vm)t = const. For MBBA, the second threshold is about 15 V, and the constant 10−3 J∕cm2. The relation is independent of current density, temperature, and thickness (greater than 10−4 cm). This phenomenon may explain variations in response as seen by different workers. A hydrodynamic model is proposed, with contributions attributable to the dielectric anisotropy.

Auger spectroscopic observation of Si☒Au mixed‐phase formation at low temperatures

T. Narusawa, S. Komiya, and A. Hiraki

Appl. Phys. Lett. 21, 272 (1972); http://dx.doi.org/10.1063/1.1654374 (2 pages) | Cited 13 times

Online Publication Date: 16 October 2003

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When a Si crystal substrate is covered with evaporated Au and heated at relatively low temperatures (100–300 °C) in an oxidizing atmosphere, because of the Si☒Au reaction at the interface, a SiO2 layer is readily formed over the Au layer. Present Auger spectroscopic study concludes that the reaction induces a Si☒Au mixed phase that is almost identical with the Si☒Au alloyed phase obtained by heat treatment in a high vacuum at temperatures well above the Si☒Au eutectic point (370 °C). The Auger spectra of Si in both the mixed and alloyed phases differ obviously from that of the pure Si crystal.

Efficient pulsed chemical laser

S.N. Suchard, A. Ching, and J.S. Whittier

Appl. Phys. Lett. 21, 274 (1972); http://dx.doi.org/10.1063/1.1654375 (2 pages) | Cited 4 times

Online Publication Date: 16 October 2003

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Output pulse observations are presented for a helium‐diluted CO2 laser pumped by VV (vibration‐vibration) energy transfer from vibrationally excited DF produced by the D2☒F2 chain reaction. Flash photolysis of the F2 served to initiate the reaction. A 290‐cm3 reaction chamber containing a 0.5‐atm mixture with mole ratio D2:F2:CO2:He = 0.33:1:8:10 gave a single‐pulse output energy of 2.8 J. Relative to the amount of D2 present in the reaction chamber, this corresponds to a chemical efficiency greater than 5%.

Self‐mode‐locking of a transversely excited N2 laser in the first positive system at 1.048 μm

T.J. Gleason, C.S. Willett, R.M. Curnutt, and J.S. Kruger

Appl. Phys. Lett. 21, 276 (1972); http://dx.doi.org/10.1063/1.1654376 (2 pages) | Cited 1 time

Online Publication Date: 16 October 2003

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An investigation has been made of the spontaneous self‐mode‐locking in a transient transversely excited N2 laser operating in the first positive system (B3πg−A 3Σu+) in molecular nitrogen on the 0–0 band at 1.048 μm. The laser emission, which had a typical pulse length of 60 nsec, consisted of a train of mode‐locked pulses of about 6‐nsec duration with a peak power of about 0.5 kW.

Effect of thick Cs☒O layers on photoemission from negative‐electron‐affinity cathodes

H. Sonnenberg

Appl. Phys. Lett. 21, 278 (1972); http://dx.doi.org/10.1063/1.1654377 (3 pages) | Cited 4 times

Online Publication Date: 16 October 2003

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The effect of thick Cs☒O layers on photoemission from GaAs and InAs0.4P0.6 cathodes is experimentally investigated. Simple empirical relationships between the yield and thickness and between the escape probability and thickness are given.

Use of rotated electrodes for amplitude weighting in interdigital surface‐wave transducers

A.P. van den Heuvel

Appl. Phys. Lett. 21, 280 (1972); http://dx.doi.org/10.1063/1.1654378 (3 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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Amplitude weighting in an interdigital surface‐wave transducer array may be achieved by misaligning the electrodes with the incident‐wave phase fronts. Since in this method all the electrodes are full aperture, the problems of diffraction loss and phase‐front distortion are avoided. Transducers employing this method of weighting to achieve a flat bandpass response were used to construct delay lines on quartz and lithium niobate, and their performance is shown to be in reasonable agreement with predictions.

Experimental investigation of electron emission of a tungsten cathode in a cesium plasma

J.H. Blom and H.J. Pels

Appl. Phys. Lett. 21, 283 (1972); http://dx.doi.org/10.1063/1.1654379 (3 pages)

Online Publication Date: 16 October 2003

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The voltage drop at a tungsten cathode surrounded by cesium plasma is measured as a function of the current density and temperature of the cathode. Current densities, an order of magnitude higher than predicted by the Langmuir S curves, accompanied with low voltage drops, have been measured for certain cathode temperature regimes. These results seem to be of interest for the emission properties of electrodes in closed‐cycle MHD generators.

High‐speed Pb1−xSnx Te photodiodes

A.M. Andrews, J.A. Higgins, J.T. Longo, E.R. Gertner, and J.G. Pasko

Appl. Phys. Lett. 21, 285 (1972); http://dx.doi.org/10.1063/1.1654380 (3 pages) | Cited 16 times

Online Publication Date: 16 October 2003

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Low‐capacitance (< 10 pF) Pb1−xSnxTe photodiodes operating near 77 °K (areas 1.7 × 10−4 cm2) have been obtained via liquid‐phase epitaxial growth of low‐carrier‐concentration material (low 1014 cm−3 to high 1015 cm−3). Response to a mode‐locked 1.06‐μm Nd:YAG laser with the devices terminated in 50 Ω indicated a frequency response to 400 MHz. With a 14‐Ω load and by exciting a photocurrent with radiation from a CO2 laser, the shot noise rolloff point was found to be 1200 MHz. Optimum parameters have not yet been achieved, as evidenced by the increase in frequency response with increase in reverse bias; these results represent only a lower limit to this material's capability.

Double‐heterostructure GaAs : Si diode lasers

J.A. Rossi and J.J. Hsieh

Appl. Phys. Lett. 21, 287 (1972); http://dx.doi.org/10.1063/1.1654381 (3 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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Double‐heterostructure diode lasers with Si‐doped active regions have exhibited laser action within the wavelength range 9100–9500 Å under pulsed room‐temperature conditions. Threshold current densities are typically 4 × 103−1.1 × 104 A∕cm2, and total power conversion efficiencies are ∼ 1–3%.

Highly anisotropic columnar structures in silicon

Lionel M. Levinson

Appl. Phys. Lett. 21, 289 (1972); http://dx.doi.org/10.1063/1.1654382 (3 pages) | Cited 9 times

Online Publication Date: 16 October 2003

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Unidirectional solidification of the CrSi2☒Si eutectic leads to formation of an oriented array of CrSi2 fibers embedded in a matrix of Si. The aligned eutectic is highly anisotropic, with resistivity parallel and perpendicular to the CrSi2 fiber alignment axis characterized by ρ⊥/ρ∥ ≈ 103−104 for a specimen produced from 100‐Ω cm Si and 99.996% iodide chromium.

Fundamental transverse electric field (TE0) mode selection for thin‐film asymmetric light guides

Yasuharu Suematsu, Mitsuari Hakuta, Kazuhito Furuya, Kazuhiro Chiba, and Ritsuo Hasumi

Appl. Phys. Lett. 21, 291 (1972); http://dx.doi.org/10.1063/1.1654383 (3 pages) | Cited 42 times

Online Publication Date: 16 October 2003

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TE0 mode selection was observed in an asymmetric dielectric light guide with a metal‐film outer coating. TM0 mode and higher‐order modes could not transmit through the guide, whereas the loss of the TE mode, the insertion loss, was small. The experimental data were in good agreement with the theoretical results given here. Filter action is explained by modal repulsion from the metal wall that is inherent in an asymmetric guide.

Intense‐electron‐beam excitation of the 3371‐Å N2 laser system

E.L. Patterson, J.B. Gerardo, and A. Wayne Johnson

Appl. Phys. Lett. 21, 293 (1972); http://dx.doi.org/10.1063/1.1654384 (3 pages) | Cited 19 times

Online Publication Date: 16 October 2003

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The results of a parametric study of superradiant laser action at 3371 Å in the second positive band system of molecular nitrogen with excitation by a high‐energy electron beam are reported. Efficiency up to 0.15% was observed for conversion of electron‐beam power to laser power at 3371 Å. Laser output power up to 24 MW in a 6‐nsec pulse was observed.

X‐ray topographic observation of moving dislocations in silicon crystals

Jun‐ichi Chikawa, Isao Fujimoto, and Takao Abe

Appl. Phys. Lett. 21, 295 (1972); http://dx.doi.org/10.1063/1.1654385 (4 pages) | Cited 11 times

Online Publication Date: 16 October 2003

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An instantaneous display of topographic images of individual dislocations was made by the combination of a high‐power x‐ray generator and a television unit with an x‐ray sensing PbO‐Vidicon camera tube. Si wafers were deformed by tension (about 300 g∕mm2) at about 1000 °C in a vacuum furnace, and, simultaneously, moving dislocations were observed continuously with the television unit. The observation of dislocations moving as fast as 0.3 mm∕sec may indicate the possibility that this technique can be a powerful tool in investigating the dynamic properties of dislocations.
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