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15 Nov 1973

Volume 23, Issue 10, pp. 531-578


A new piezoelectric crystal: Ba2Ge2TiO8

Masakazu Kimura, Kikuo Doi, Satoshi Nanamatsu, and Tsutomu Kawamura

Appl. Phys. Lett. 23, 531 (1973); http://dx.doi.org/10.1063/1.1654737 (2 pages) | Cited 24 times

Online Publication Date: 9 October 2003

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A Ba2Ge2TiO8 single crystal is synthesized by the Bridgman method. The space group of Ba2Ge2TiO8 is determined to be C2v21‐Iba2, where the lattice constants a, b, and c are 12.30, 135.2, and 10.70 Å, respectively. The crystal includes a wedge‐shaped domain structure which resembles those observed in Gd2(MoO4)3 and Rochelle salt. Both X and Y plates have a large electromechanical coupling factor in a thickness shear mode, k15 = 0.27 and k24 = 0.31.

Stress compensation in Ga1−xAlxAs1−yPy LPE layers on GaAs substrates

G. A. Rozgonyi and M. B. Panish

Appl. Phys. Lett. 23, 533 (1973); http://dx.doi.org/10.1063/1.1654738 (3 pages) | Cited 31 times

Online Publication Date: 9 October 2003

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Epitaxial layers of Ga0.66Al0.34As1−yPy with y ≤ ≈ 0.04 have been grown in order to demonstrate that it is possible to adjust the lattice parameter of a mixed III‐V layer such that it is matched with the GaAs substrate at room temperature. The amount of stress compensation has been determined as a function of y, as well as estimates of the layer thicknesses required to suppress the formation of misfit dislocations.

Phase of ultrasonic reflection at Rayleigh angle incidence

Thomas J. Plona and Walter G. Mayer

Appl. Phys. Lett. 23, 536 (1973); http://dx.doi.org/10.1063/1.1654739 (3 pages)

Online Publication Date: 9 October 2003

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The phase of an ultrasonic beam reflected from a liquid‐solid interface at and near Rayleigh angle incidence is measured using a new technique. Results indicate that two waves comprise the reflected beam, i.e., a specularly reflected wave and a reradiated surface wave, which do not change phase as the angle of incidence varies, which maintain a 180° phase difference between them, and which propagate collinearly only at the Rayleigh angle.

Self‐focusing of laser light in the isotropic phase of a nematic liquid crystal

D. V. G. L. Narasimha Rao and S. Jayaraman

Appl. Phys. Lett. 23, 539 (1973); http://dx.doi.org/10.1063/1.1654740 (2 pages) | Cited 19 times

Online Publication Date: 9 October 2003

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Self‐focusing of ruby laser light is studied as a function of sample length and temperature in the isotropic phase of nematic liquid‐crystal MBBA. The critical power for self‐focusing, 0.36 kW, observed near the phase transition temperature is a factor of 20 times less than that for CS2. The corresponding nonlinear index 4.4 × 10−10 esu is the largest value known so far for any material.

Electron irradiation dilatation in SiO2

R. A. Sigsbee and R. H. Wilson

Appl. Phys. Lett. 23, 541 (1973); http://dx.doi.org/10.1063/1.1654741 (2 pages) | Cited 8 times

Online Publication Date: 9 October 2003

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Negative dilatation (shrinkage) induced by 10‐keV electron bombardment of SiO2 films thermally grown on Si has been studied. Measured deflection changes in continuous SiO2 bridges etched following irradiation showed a maximum shrinkage of [inverted lazy s] 0.8%, which occurred at 0.2 C∕cm2, followed by a slight expansion, and subsequent saturation at higher exposures. Exposures up to 3 C∕cm2 were utilized. Isochronal annealing studies show the activation energy for recovery to be approximately 1 eV with 2% recovery occurring in 1 h at 400°C.

Brillouin spectra of CaF2 microcrystals using a stable 3‐pass Fabry‐Perot interferometer

E. Brody, C. Roychoudhuri, and M. Hercher

Appl. Phys. Lett. 23, 543 (1973); http://dx.doi.org/10.1063/1.1654742 (3 pages) | Cited 3 times

Online Publication Date: 9 October 2003

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The elastic properties of single‐crystal grains in polycrystalline material can be studied through Brillouin scattering using a laser probe beam. The Brillouin spectra of hot‐pressed CaF2 (Irtran‐3), having a typical grain size of 150 μm, is presented. We have observed scattering from both longitudinal and transverse phonons, despite the presence of a large elastically scattered signal, using a stable 3‐pass Fabry‐Perot interferometer having a contrast of 106.

Electrical properties of proton‐bombarded Ga1−xAlxAs

P. N. Favennec and D. Diguet

Appl. Phys. Lett. 23, 546 (1973); http://dx.doi.org/10.1063/1.1654743 (2 pages) | Cited 4 times

Online Publication Date: 9 October 2003

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We have shown the feasibility of forming insulating walls in Ga1−xAlxAs by proton bombardment, and have demonstrated their stability up to a temperature of 180°C. The mean projected range of protons in Ga1−xAlxAs is determined for energies ranging from 200 to 1200 keV. The insulating properties of proton‐bombarded layers are applied to the realization of cross‐bar integrated arrays of electroluminescent diodes.

Spark pumped dye laser with high repetition rate and low threshold

C. M. Ferrar

Appl. Phys. Lett. 23, 548 (1973); http://dx.doi.org/10.1063/1.1654744 (2 pages) | Cited 2 times

Online Publication Date: 9 October 2003

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A short unconfined spark is imaged by a spherical reflector into a small dye cell. Lasing is achieved for electrical inputs as small as 5 mJ. Pulse repetition rates as high as 2000 pulses∕sec (pps) have been attained. A tilted etalon permits wavelength tuning of the laser output.

Peaked structure in field‐effect mobility of silicon MOS transistors at very low temperatures

J. A. Pals and W. J. J. A. van Heck

Appl. Phys. Lett. 23, 550 (1973); http://dx.doi.org/10.1063/1.1654745 (3 pages) | Cited 12 times

Online Publication Date: 9 October 2003

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Field‐effect mobility measurements on silicon n‐ and p‐channel MOS transistors at temperatures of 4.2 K and lower are reported. The measured field‐effect mobility as a function of the gate voltage shows an anomalous peaked structure superimposed on the well‐known over‐all behavior. These peaks are possibly due to statistical fluctuations within the bands of the semiconductor of the density of surface states as a function of the energy.

Defects in arsenic‐implanted p‐n junctions

E. H. Bogardus and M. R. Poponiak

Appl. Phys. Lett. 23, 553 (1973); http://dx.doi.org/10.1063/1.1654746 (3 pages) | Cited 4 times

Online Publication Date: 9 October 2003

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High‐dose (300 keV) ion implant damage has been observed, by infrared microscopy, to extend approximately 1.4 times the junction depth or 4 times the projected range. No such damage has been seen for shallow implants that were diffused to a corresponding junction depth. Leakage currents were identical for both implant conditions. No ``tailing'' was identified in the profile that could explain the extent of damage.

Fast acoustic diffraction‐type optical waveguide modulator

Manhar L. Shah

Appl. Phys. Lett. 23, 556 (1973); http://dx.doi.org/10.1063/1.1654747 (3 pages)

Online Publication Date: 9 October 2003

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A fast acoustic diffraction‐type thin‐film optical waveguide modulator is described. Modulation was observed for the drive signal over the 150–550‐MHz frequency range. A depth of modulation of 10% per electrical watt was estimated from the diffracted spots. The scheme presented here widens the selection of materials for acousto‐optic modulations in an optical waveguide and may find some useful applications in the infrared region where suitable electro‐optic materials are few.

Electron‐beam‐initiated chemical laser in SF6☒H2 mixtures

Rolf W. F. Gross and F. Wesner

Appl. Phys. Lett. 23, 559 (1973); http://dx.doi.org/10.1063/1.1654748 (3 pages) | Cited 8 times

Online Publication Date: 9 October 2003

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A 3.5‐cm × 35‐cm planar field emission electron beam diode, producing a total beam current of 4.65 kA of 120‐keV electrons in 26‐nsec pulses was used to initiate the reaction of F with H2 in SF6☒H2 mixtures. From an optical volume of approximately 1 liter we observed HF laser pulses of 20–30 nsec duration with a maximum energy of 0.2 J at 450 Torr. The application of a secondary potential, very near the self‐breakdown limit of the gas, to the laser medium increased the laser output by only a factor of 2. Numerical analysis of the experiments without secondary field shows that 2.7 × 104 F atoms are produced by each 120‐keV electron fully stopped in the gas. This corresponds to an energy of 4.5 eV required for the production of one F atom from SF6 by high‐energy electrons. The conversion efficiency of electron beam energy input to the medium to laser output energy was 5.2%.

Continuously tunable high‐pressure CO2 laser with uv photopreionization

A. J. Alcock, K. Leopold, and M. C. Richardson

Appl. Phys. Lett. 23, 562 (1973); http://dx.doi.org/10.1063/1.1654749 (3 pages) | Cited 39 times

Online Publication Date: 9 October 2003

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The operation of a uv photoinitiated tranverse‐discharge CO2 laser has been investigated at pressures up to 15 atm. Preliminary studies of a device having an active volume of [inverted lazy s] 13 cm3 have yielded a maximum output of [inverted lazy s] 1 J in 30 nsec, while the use of a grating‐tuned resonator has resulted in continuously tunable operation over frequency intervals of [inverted lazy s] 20 cm−1.

HF and DF lasers by direct electrical discharge excitation

S. R. Byron, L. Y. Nelson, and G. J. Mullaney

Appl. Phys. Lett. 23, 565 (1973); http://dx.doi.org/10.1063/1.1654750 (3 pages) | Cited 5 times

Online Publication Date: 9 October 2003

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Using a high‐current long‐pulse electron‐beam‐stabilized electrical discharge, laser oscillation has been observed on several vibration‐rotation bands of HF and DF in mixtures containing less than 1% HF or DF. Results in HF∕argon mixtures with 10% added N2, H2, or D2 established that HF is vibrationally pumped by direct electron impact and also by vibrational energy transfer from H2. Rotational nonequilibrium as well as cascade coupling between 3 → 2 lines and 2 → 1 lines were inferred from the time sequence of the laser emission.

Saturated resonance spectroscopy of SiF4

John Nella

Appl. Phys. Lett. 23, 568 (1973); http://dx.doi.org/10.1063/1.1654751 (3 pages) | Cited 9 times

Online Publication Date: 9 October 2003

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The small‐signal absorption coefficient of silicon tetrafluoride (SiF4) at the 9.6‐μm CO2 laser wavelength has been measured by means of saturated spectroscopy. The Lamb dip spectrum of the SiF4 transitions in coincidence with five CO2 9.6‐μm P‐branch transitions has been observed. Measurements of the pressure dependence of the Lamb dip width were made, resulting in a determination of the SiF4☒SiF4 cross section for phase interruption collisions. The saturation intensity was experimentally found to be quadratic with pressure, in a limited pressure range, and an upper bound for the Einstein A coefficient was determined.

Beam deflection and amplitude modulation of 10.6‐μm guided waves by free‐carrier injection in GaAs☒AlGaAs heterostructures

J. H. McFee, R. E. Nahory, M. A. Pollack, and R. A. Logan

Appl. Phys. Lett. 23, 571 (1973); http://dx.doi.org/10.1063/1.1654752 (3 pages) | Cited 8 times

Online Publication Date: 9 October 2003

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Beam deflection and amplitude modulation of 10.6‐μm guided waves by photoinjected free carriers are demonstrated in thin‐film GaAs☒AlGaAs heterostructure waveguides. At high injection levels (N≳5×1017 cm−3), amplitude modulation (up to 100%) of the 10.6‐μm guided wave dominates, but at lower injection levels beam deflection is dominant. External deflection angles of the order of 1° are obtained with nanosecond response times.

Closed‐form solution for excited‐state populations in temporally and spatially varying lasing media

B. P. Curry, S. A. Zwick, and C. D. Aliprantis

Appl. Phys. Lett. 23, 574 (1973); http://dx.doi.org/10.1063/1.1654753 (2 pages)

Online Publication Date: 9 October 2003

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We solve a class of equations in which excited‐state populations are coupled by radiative, collisional, and pumping terms having specified time and position dependence. These equations are decoupled by expansion of the excited‐state populations and the pumping terms in eigenvectors of the collisional transition matrix. The solutions are ordered in such a way that the first‐order solution is equivalent to neglecting temporal variations in radiation intensity, and higher‐oder solutions introduce time‐dependent state mixing effects as a consequence of strong transitions. The second‐order solution is stated explicitly and a prescription given for obtaining higher‐order corrections.

New magneto‐optic memory concept based on compensation wall domains

J. ‐P. Krumme and P. Hansen

Appl. Phys. Lett. 23, 576 (1973); http://dx.doi.org/10.1063/1.1654754 (3 pages) | Cited 14 times

Online Publication Date: 9 October 2003

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A new concept of thermomagnetic localized reversible magneto‐optic storage is proposed based on the application of compensation wall domains (CWD). Individual CWD's of 12 × 12‐μm dimensions in an LPE film of composition Y2.34Gd0.52Yb0.14Fe3.74Ga1.26 O12 with 3‐μm thickness have been switched by laser flashes of 10−2 erg∕μm2 energy in 5 μs at 5145‐Å wavelength using a stationary field of 41 Oe normal to the film plane.
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