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15 May 1972

Volume 20, Issue 10, pp. 375-408


Ga1−xAlxAs LED Structures Grown on GaP Substrates

J. M. Woodall, R. M. Potemski, S. E. Blum, and R. Lynch

Appl. Phys. Lett. 20, 375 (1972); http://dx.doi.org/10.1063/1.1653981 (3 pages) | Cited 6 times

Online Publication Date: 22 October 2003

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Ga1−xAlxAs light‐emitting diode structures have been grown on GaP substrates by the liquid‐phase‐epitaxial method. In spite of the large differences in lattice constants and thermal‐expansion coefficients, room‐temperature efficiencies up to 5.5% in air have been observed for a peak emission of 8500 Å. Previously, in order to achieve high external efficiencies it was necessary to grow thick Ga1−xAlxAs layers on GaAs substrates and then remove the substrate. However, using undoped GaP substrates, which are transparent to the infrared and red portions of the spectrum, thin structures of Ga1−xAlxAs with large external efficiencies can now be made.

Measurement of the Gain Line Shape of a Gas Laser Using a Tunable Semiconductor Laser

F. A. Blum, K. W. Nill, A. R. Calawa, and T. C. Harman

Appl. Phys. Lett. 20, 377 (1972); http://dx.doi.org/10.1063/1.1653982 (3 pages) | Cited 4 times

Online Publication Date: 22 October 2003

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Using a cw tunable PbS0.6Se0.4 semiconductor diode laser operating near 5.3 μm we have fully resolved the gain (loss) line shape of several vibration‐rotation lines of a CO gas laser amplifier.

Broadening of Fast‐Beam Spectral Lines Due to Diffraction at the Entrance Slit of a Spectrometer

John A. Leavitt and John O. Stoner

Appl. Phys. Lett. 20, 379 (1972); http://dx.doi.org/10.1063/1.1653983 (2 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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We show experimentally and theoretically that adjustment of a spectrometer for observation of fast‐beam spectral lines under conditions of minimum linewidth requires consideration of the effects of diffraction at the spectrometer's entrance slit. We obtain an approximate expression for the optimum entrance slit width to be used in order to avoid the pronounced broadening of the spectral lines that occurs for very narrow entrance slits.

Amplitude‐Dependent Shear Wave Attenuation near Tc in Rhenium

D. A. Robinson and M. Levy

Appl. Phys. Lett. 20, 381 (1972); http://dx.doi.org/10.1063/1.1653984 (2 pages)

Online Publication Date: 22 October 2003

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A novel approach using a mixed‐mode transducer for measuring shear‐wave attenuation near Tc in rhenium has been used to show that the shape of the attenuation curve depends on the ultrasonic wave amplitude.

Submillimeter Wave Generation by Difference‐Frequency Mixing in GaAs

T. J. Bridges and A. R. Strnad

Appl. Phys. Lett. 20, 382 (1972); http://dx.doi.org/10.1063/1.1653985 (3 pages) | Cited 16 times

Online Publication Date: 22 October 2003

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Non‐phase‐matched generation of 29.9 cm−1 is obtained by difference mixing of pulsed CO2 laser radiation in room‐temperature GaAs, with a detection signal‐to‐noise ratio of 103. Calculations show that comparable results could be obtained from 10 to 200 cm−1.

Novel GaAs☒(AlGa)As Cold‐Cathode Structure and Factors Affecting Extended Operation

H. Schade, H. Nelson, and H. Kressel

Appl. Phys. Lett. 20, 385 (1972); http://dx.doi.org/10.1063/1.1653986 (3 pages) | Cited 15 times

Online Publication Date: 22 October 2003

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A novel planar cold‐cathode structure has been developed based on a GaAs☒(AlGa)As heterojunction and a negative electron affinity GaAs surface. As an important feature of the device, the lateral confinement of the current flow to the desired area of the emitting surface is obtained by the selective diffusion of zinc. Under pulsed conditions, emission efficiencies as high as 4% and emission current densities as high as 7 A∕cm2 have been achieved. The release of impurities from the anode as a result of electron‐stimulated desorption has been found to be a major factor affecting the cathode life under dc operation. The influence of this factor can be greatly minimized by different techniques such as using low anode voltages and magnetic field deflection.

Mössbauer Effect of 57Fe and 119Sn Atoms Isolated in Solid Nitrogen

H. Micklitz and P. H. Barrett

Appl. Phys. Lett. 20, 387 (1972); http://dx.doi.org/10.1063/1.1653987 (3 pages) | Cited 12 times

Online Publication Date: 22 October 2003

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The Mössbauer resonances of nitrogen‐matrix‐isolated 57Fe and 119Sn atoms have isomer shifts, which are within the experimental errors, identical with the isomer shifts of the same atoms isolated in rare‐gas matrices. Despite an observed quadrupole splitting of the 57Fe and 119Sn resonances, the relatively small photoelectric cross section of nitrogen makes the nitrogen matrix useful for matrix‐isolation Mössbauer studies of nuclei which require relatively thick Mössbauer absorbers.

Convolution of Surface Waves in a Structure of Semiconductor on LiNbO3

Wen‐Chung Wang

Appl. Phys. Lett. 20, 389 (1972); http://dx.doi.org/10.1063/1.1653988 (4 pages) | Cited 10 times

Online Publication Date: 22 October 2003

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We report here some experimental results on surface‐wave convolution in a structure of Si on LiNbO3 or of CdS on PZT. The semiconductor plate is dc biased. Convolved signals at both the sum and difference frequencies have been observed from the terminals attached to the semiconductor. A simple expression is obtained on the convolved signal amplitude vs the difference in wave vectors of the two input signals. The experiment is in general agreement with the theory. A series of pictures on the convolved signal as a function of the applied dc field is presented.

Observation of Two‐Photon Conductivity in GaAs with Nanosecond and Picosecond Light Pulses

S. Jayaraman and C. H. Lee

Appl. Phys. Lett. 20, 392 (1972); http://dx.doi.org/10.1063/1.1653989 (4 pages) | Cited 38 times

Online Publication Date: 22 October 2003

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The effect of photoconductivity in GaAs single crystals was investigated by using both nanosecond and picosecond light pulses for excitation. Both steady‐state and transient responses of photoconductivity have been observed.

Transverse Excitation Pulsed Laser in Gas‐Dynamically Cooled Mixtures

E. Vallach, A. Zeevi, E. Greenfield, and S. Yatsiv

Appl. Phys. Lett. 20, 395 (1972); http://dx.doi.org/10.1063/1.1653990 (3 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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We report laser emission from a pulsed transverse electric discharge in fast‐flowing adiabatically cooled gas mixtures. The discharge is in the downstream parallel section of a supersonic nozzle. Both electrical excitation of CO2 and CO and chemical excitation of CO in the reaction of CS2 + O2 yield laser emission. The cooling in the nozzle is demonstrated by the low J values of the observed transitions. The gain for CO transitions was more than an order of magnitude greater at the low temperatures than at room temperature. Fast cooling during the supersonic expansion permits lasing in highly supersaturated gas mixtures. This extends laser operation to temperatures beyond the capability of cryogenic methods and permits higher laser energies and efficiencies.

Optical Generation of Intense Picosecond Electrical Pulses

D. H. Auston and A. M. Glass

Appl. Phys. Lett. 20, 398 (1972); http://dx.doi.org/10.1063/1.1653991 (2 pages) | Cited 22 times

Online Publication Date: 22 October 2003

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Electrical pulses, 4 A in 10 psec, have been generated by rectification of 1.06‐μm pulses in LiTaO3: Cu++. Their amplitude and duration were measured by photographing the birefringence induced by the pulses propagating along an electro‐optic transmission line illuminated transversely in a Pockel's cell arrangement. The principal mechanism responsible for the generation is the macroscopic polarization resulting from the difference in dipole moment between the ground and excited states of the absorbing Cu++ impurities.

Radiation‐Damage‐Induced Apparent Optical Absorption Interpreted as Scattering from Defect Zones

R. L. Meek, W. M. Gibson, C. G. Maclennan, and D. M. Maher

Appl. Phys. Lett. 20, 400 (1972); http://dx.doi.org/10.1063/1.1653992 (4 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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Radiation‐induced apparent optical absorption in the wavelength range 0.5–2.5 μ of thin silicon crystals, which were irradiated with 1.8‐MeV He+ ions, is interpreted in terms of scattering from defect zones. Fitting the absorption and refractive index data to the predictions of Mie scattering theory allows determination of the average size, number, and refractive index of the defect zones. For 1015–1016 ions cm−2 incident on a crystal 2.8 μ thick, this analysis indicated a zone radius of about 2200 Å, a refractive index for the zone of about 1.04 times that of undamaged silicon independent of wavelength, and ∼ 10−7 zones produced per incident ion. At larger fluence, the zone size increased and the number of zones decreased. Transmission‐electron‐microscopy (TEM) observations confirm the presence of defective zones whose geometry, size, and number density are in reasonable agreement with the theoretical predictions.

CO2 Waveguide Lasers

T. J. Bridges, E. G. Burkhardt, and P. W. Smith

Appl. Phys. Lett. 20, 403 (1972); http://dx.doi.org/10.1063/1.1653993 (3 pages) | Cited 44 times

Online Publication Date: 22 October 2003

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Compact cw single‐mode CO2 : He : N2 lasers with a 1‐mm‐diam dielectric waveguide discharge tube have exhibited gains of up to 37 dB∕m, volumetric power outputs of 15 W∕cm3, and saturation parameters of 3600 W∕cm2 with a coolant temperature of −70°C. With tap water cooling at 20°C the corresponding values were 24 dB∕m, 9.5 W∕cm3, and 2100 W∕cm2. All of these values are substantially larger than those obtained with conventional CO2 lasers. A 12.5‐cm‐long waveguide tube with an active volume of 0.096 cm3 gave a power output of 1.4 W at −70°C and 0.9 W at 20°C coolant temperature.

Dye Laser Forced Oscillator

G. Magyar and H. ‐J. Schneider‐Muntau

Appl. Phys. Lett. 20, 406 (1972); http://dx.doi.org/10.1063/1.1653994 (3 pages) | Cited 14 times

Online Publication Date: 22 October 2003

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The narrow‐band output of a small flashlamp‐pumped coaxial dye laser is injected internally into a large close‐coupled oscillator. When frequency locked, an effective power gain of ∼ 4000 and an energy output of ∼ 600 mJ in a width of ∼ 0.01 nm is achieved.
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