bluuebunny/crossref_metadata_2025 huggingface dataset:
Phases Observed in Oxygen-Reactive Sputtering of Tantalum
Authors: Feinstein L. G.
Published: January 2004

Ta films were deposited by dc diode sputtering in Ar–O2. The crystalline structure of the deposited films was investigated by wide-film Debye-Scherrer x-ray diffraction. Films were β-Ta at low O2 partial pressures, passing through a crystalline suboxide to the bcc phase with increasing O2 content. The results contradict recent suggestions that β-Ta is formed to accommodate higher impurity levels.
Required Monochromaticity of an Electron Beam Modulated at Optical Frequencies
Authors: Schwarz Helmut
Published: January 2004

It is shown theoretically and experimentally that for the observation of the modulation of an electron beam at optical frequencies the energy spread of the electrons should remain below a value determined by the electron energy, the light frequency, and the distance between interaction zone and observation screen.
Correlation of Defect-Impurity Interactions in GaP with Local Variations in Photoluminescence
Authors: Rozgonyi G. A. , Afromowitz Martin A.
Published: January 2004

A direct correlation between small-scale spatial inhomogeneities in the photoluminescent efficiency of GaP LEC wafers and local variations in the density of shallow saucer-shaped chemical etch pits has been made. These variations are particularly evident in the vicinity of dislocations, suggesting that the dislocations act as a sink for the impurity or crystal defect responsible for the formation of saucer pits. In addition, larger-scale spatial variations in PL efficiency and saucer-pit density, believed to be related to the LEC crystal-growth procedure, are mirrored in the contrast obtained on Borrmann x-ray topographs.
Possibility of a Unidirectional Laser Amplifier Produced by Monochromatic Optical Pumping of a Coupled Doppler-Broadened Transition
Authors: Skribanowitz N. , Feld M. S. , Francke R. E. , Kelly M. J. , Javan A.
Published: January 2004

An optically pumped gas laser amplifier is described which exhibits gain only for waves traveling in a given direction while absorbing waves traveling in the opposite direction. The idea is based on the laser-induced line-narrowing effect in coupled Doppler-broadened transitions for the case of a high-intensity monochromatic pump field.
Surface Lasers
Authors: Varsanyi F.
Published: January 2004

Room-temperature visible laser action is reported in PrCl3 and PrBr3. Optical pumping directly into the upper laser level is accomplished by a wavelength-tunable dye laser. Threshold is less than 1 μJ. Superradiant laser action within physical dimensions of a few microns is generated by focusing the excitation light on the cleaved crystal surface. Use as an active element in integrated optics networks is indicated with over 106 individual lasers per square inch.
Low-Temperature Proton Radiation Damage and Recovery in Discontinuous Ta Films
Authors: Hardy W.R. , Pronko P.P. , Shewchun J.
Published: January 2004

Tantalum films reactively sputtered in oxygen and nitrogen simultaneously have been irradiated by 150-keV protons at 30°K. The observed conductance increase of these discontinuous films is ascribed to radiation-produced defect levels within the interisland oxide regions. The nonlinearity of the conductance increase with fluence may be accounted for by a combination of close-pair thermal annealing and spontaneous recombination. Isochronal annealing experiments demonstrate that recovery occurs in two main stages. The first stage (34–120°K) is attributed to close-pair or correlated recombination, and the second stage (200–300°K) is attributed to uncorrelated migration of defects to the gap-island interface.
The Effect of Nitrogen Doping on GaAs1−xPx Electroluminescent Diodes
Authors: Groves W.O. , Herzog A.H. , Craford M.G.
Published: January 2004

The efficiency of GaAs1−xPx diodes for x>0.45 has been found to be greatly enhanced by the addition of nitrogen doping. The diodes were fabricated by means of Zn diffusion into vapor-grown GaAs1−xPx doped with N and Te. The effects of nitrogen doping on diode efficiency, emission spectra, and brightness as a function of alloy composition are discussed.
Origin of Acoustoelectric Flux Domains in Conducting CdS
Authors: Many A. , Gelbart U.
Published: January 2004

Brillouin-scattering measurements show that in homogeneous CdS samples, propagating flux domains originate solely from the shock produced at the cathode boundary by the pulse onset. If the shock is properly suppressed, no domains are formed, the spatial and frequency distribution of the flux being then in complete accord with the predictions of the small-signal theory based on amplication of the rmal background noise. The enhanced parametric downconversion observed within the domain is mainly attributed to low-frequency shock-excited flux which acts in this case as the stimulating signal.
Quenching of Radiation from Ionized Gases by Infrared Photons
Authors: Kaplafka J. P. , Merkelo H. , Goldstein L.
Published: January 2004

Visible afterglow radiations from low-pressure weakly ionized inert gases are partially quenched during irradiation of the gases by the infrared produced with CO2 lasers (photon energies ∼ 0.1 eV). The most plausible interpretation of the effect appears to involve photoionization or photoexcitation of neutral atoms in excited states populated during the process of recombination.
Low-Carrier-Concentration Liquid Epitaxial Pb1−x Snx Te
Authors: Longo J. T. , Gertner E. R. , Joseph A. S.
Published: January 2004

We have achieved multiple-layer liquid epitaxial growth of Pb1−xSnx Te from Pb–Sn solution. Hall-effect and capacitance measurements determine carrier concentrations to be as low as 3 × 1015 cm−3 at 77 °K. Interference microscopy reveals that deviations from planarity of the grown surface are less than 1 μm over an area of 1 mm2.
Production of Vacancies by Laser Bombardment
Authors: Metz S. A. , Smidt F. A.
Published: January 2004

Vacancy concentrations estimated to be as large as 1 at. % have been induced in pure nickel and vanadium foils by bombardment with high-intensity laser pulses. Annealing bombarded foils at temperatures greater than 0. 3Tm (absolute melting point) allows vacancies to form into aggregates. Examples are shown of voids in nickel and faulted loops in vanadium. Possible mechanisms of vacancy generation are discussed.
Theoretical Description of the Electrical CO Laser
Authors: Center R. E. , Caledonia G. E.
Published: January 2004

A pumping mechanism based on vibrational energy exchange under thermal nonequilibrium conditions is used to predict the performance of the electrical CO laser. Qualitative agreement has been obtained for the power spectral distribution and the cavity flux at several gas temperatures, indicating that this vibrational exchange process may be the dominant mechanism in the highly efficient electric CO laser.
Low-Loss Image for Surface Scanning Electron Microscope
Authors: Wells Oliver C.
Published: January 2004

Images have been obtained from the surface scanning electron microscope (SEM) by collecting backscattered electrons that have suffered a small energy loss in the specimen. This method can be applied to smooth specimens when viewed at oblique incidence. The modulation depth in the electron channelling pattern can be as great as 75%, as compared with 2–5% for the secondary electron signal or 40% for the backscattered electron signal. In surface microscopy, the image is obtained from a surface layer of thickness about 100 Å, so that the effects of electron penetration are greatly reduced. A point-to-point resolution of 170 Å has been obtained.
Intercavity Scanning of a CO2 Laser by Electron-Beam-Trigger Excitatior
Authors: Beiser Leo
Published: January 2004

A CO2 laser in a transversely degenerate resonator was induced to lase by a localized electron-beam-triggering technique, thereby achieving intercavity mode selection. The CO2 idler and electron-beam-triggered driver stages were positioned in individual legs of a split confocal resonator. The successful testing of this incremental excitation process is now reported, along with the motivation for localized gain control for internally scanned lasers.
Mode Locking of the cw Dye Laser
Authors: Kuizenga D. J.
Published: January 2004

A cw dye laser has been mode locked with a LiNbO3 phase modulator. Good mode locking was difficult to obtain. Pulses ∼500 psec wide with substructure at the detector resolution were observed. With an internal thin etalon, shorter pulses were observed with very distinct substructure at the detector resolution. Under certain circumstances pulses 200 psec wide were obtained.
Wideband CO2 Laser Second Harmonic Generation Phase Matched in GaAs Thin-Film Waveguides
Authors: Anderson D. B. , Boyd J. T.
Published: January 2004

Phase-matched CO2 laser second harmonic generation has been observed in GaAs thin-film waveguides. Phase matching is accomplished through the use of dielectric waveguide dispersion. Large values of the phase-matched bandwidth are observed and attributed partly to the nature of waveguide phase matching and partly to tapering of the waveguide thickness.
Electronic Tuning of a Dye Laser Using the Acousto-Optic Filter
Authors: Taylor D. J. , Harris S. E. , Nieh S. T. K. , Hansch T. W.
Published: January 2004

A dye laser which is electronically tunable over 780 Å has been obtained by inserting a CaMoO4 acousto-optic filter into the dye-laser cavity. A filter half-power linewidth of 6.8 Å yields a laser linewidth of 1.35 Å. Oscillation at two simultaneous independently tunable wavelengths and electronically variable output coupling has been observed.
In1−xGaxP p-n Junction Lasers
Authors: Macksey H. M. , Holonyak N. , Scifres D. R. , Dupuis R. D. , Zack G. W.
Published: January 2004

The laser operation of In1−xGaxP (x∼0.27) p-n junctions is demonstrated at 4.2 and 77°K. The n-type material for the junctions is grown at a fixed temperature (900–950°C) from an In solution with the InP and GaP source crystal introduced into the solution at slightly higher temperature. The p-n junctions are formed at 700°C by Zn diffusion from an In + 10% Zn source. In comparison with InP, the threshold currents for In1−xGaxP junctions are large, which is attributed to the problems associated with introducing Zn into the In–Ga sublattice.
Correlation between Backward Stimulated Raman Pulse and Moving Focus in Liquids
Authors: Loy M. M. T. , Shen Y. R.
Published: January 2004

We have studied the correlation between backward stimulated Raman pulse and small-scale ``filament'' induced by a Q-switched laser pulse in Kerr liquids. We show that the filament is the result of a moving focus and that the backward Raman pulse is initiated by the moving focus inside the liquid cell.
Channel Shortening in MOS Transistors during Junction Walk-Out
Authors: Neugebauer C. A. , Burgess J. F. , Joynson R. E. , Mundy J. L.
Published: January 2004

The walk-out of the breakdown voltage of the junctions of p-channel MOS transistors was found to be accompanied by an increase in the transconductance. An explanation for this relationship is offered here in terms of electron injection into the gate oxide near the junctions, and subsequent trapping there. The rate of junction walk-out depends not only on the total injected negative charge, but also on the value of the injection current itself, increasing at higher injection currents. The ratio of the injection current to the total junction current is found to decrease with increasing breakdown voltage.
Room-Temperature cw Operation of a GaAs1−xPx Diode-Pumped YAG:Nd Laser
Authors: Ostermayer F. W. , Allen R. B. , Dierschke E. G.
Published: January 2004

Room-temperature (20°C) cw operation of a YAG: Nd laser pumped by GaAs1−xPx electroluminescent diodes is reported. A linear array of sixty-four 0.46-mm-diam domed diodes was coupled to a 1.5-mm-diam × 50-mm-long laser rod by a semielliptical cylindrical reflector. At an electrical input to the diode array of 30 W, the optical pumping power was 0.90 W (average diode efficiency ≈ 3%) and the laser output power was 1.4 mW. The laser was also operated with 1- and 2-msec pulses of pump power. At an electrical input of 30 W, the laser output at the end of a 1-msec pulse was 4.9 mW, and at an electrical input of 44 W, the output was 15.7 mW. The discrepancy between the pulsed and cw output powers has been attributed primarily to heating effects in the diodes. When the laser rod was cooled to 0°C, the pulsed output at an input of 44 W was 55 mW.
Comment on ``Formation of Vacancy Pits on the Surface of Aluminum on Quench Annealing''
Authors: Wyon G. , Brichet C. , Roques-Carmes C.
Published: January 2004

Quench-annealing experiments on aluminum (99.995% purity) have shown that vacancy condensation pits on the surface can only be formed when the annealing temperature is 200°C or more. In contrast to slow-cooling treatments, the pit distribution is then uniform over the whole surface; no depleted zones are observed around grain boundaries and subboundaries. There is a strong disagreement between our own results and Tariyal and Ramaswami's paper which showed pit formation by quench annealing at 20 and 50°C. The reasons for such a disagreement are discussed.
Modification of Magnetic Anisotropy in Garnets by Ion Implantation
Authors: Wolfe R. , North J. C. , Barns R. L. , Robinson M. , Levinstein H. J.
Published: January 2004

Ion implantation into epitaxial films of certain magnetic garnets grown on nonmagnetic substrates has produced layers with uniaxial anisotropy suitable for magnetic ``bubble'' formation and propagation. Implantation of hydrogen or lithium ions causes the garnet lattice to expand and the constraint of the unimplanted material places the implanted layer in lateral compression. In garnets with positive magnetostriction, this stress results in an induced easy axis of magnetization perpendicular to the surface. Helium-ion implantation does not cause lattice expansion or induce magnetic anisotropy. This suggests that the phenomenon is due to a chemical effect rather than lattice damage.
Temperature Measurements of Plasmas Produced by Laser Pulses in Gas Jets
Authors: Neusser H. J. , Puell H. , Kaiser W.
Published: January 2004

Laser-produced plasmas generated in a freely expanding N2 gas jet of high density are investigated experimentally. Measured values for the electron temperature and the time of light-plasma interaction are presented as a function of the incident light power. The results are compared with existing theories.
Observation of Pulsation from a Double-Heterostructure Injection Laser Due to Lateral Optical Coupling
Authors: Kobayashi K. , Yonezu H. , Saito F. , Nannichi Y.
Published: January 2004

A new type of pulsation was observed in the output from a (GaAl)As double-heterostructure injection laser which happened to have two lasing filaments closely located to each other. We observed repetitive pulsed lasing in one filament and corresponding dipping in the other. This pulsation was interpreted to be due to lateral optical coupling between the two filaments.
Focusing of a Light Beam by a Concave Magnetic Domain Wall in Yttrium Orthoferrites
Authors: Shoji Masakazu , Goldstein Richard M. , Tabor William J.
Published: January 2004

We have observed the convergence of a light beam that has passed through a concave boundary of magnetic domains in orthoferrites. We have developed a simple theory that explains the phenomenon.
Ga1−xAlxAs Produced by Al+ Ion Implantation of GaAs
Authors: Hunsperger R. G. , Marsh O. J.
Published: January 2004

GaAs has been converted to Ga1−xAlxAs by implanting GaAs substrates with 30-KeV Al+ ions and subsequently annealing at 900 °C. The maximum ion dose used was 2×1016/cm2, corresponding to a calculated peak concentration of approximately 1022 Al atoms/cm3. The emission spectra of electroluminescent diodes formed in the material were measured.
A Two-Frequency Coincidence Addressing Scheme for Nematic-Liquid-Crystal Displays
Authors: Stein C. R. , Kashnow R. A.
Published: January 2004

We describe a new coincidence addressing plan for nematic-liquid-crystal dynamic-scattering displays which is based on the temporal coincidence of low- and high-frequency electrical signals. The experimental threshold-voltage condition is in agreement with that calculated from an extension of Helfrich's conduction-induced alignment model.
Flashlamp-Pumped Laser Dyes: A Literature Survey
Authors: Warden J. T. , Gough Lucille
Published: January 2004

Fifty-nine flashlamp-pumped laser dyes are tabulated with their literature references. Lasing wavelengths and appropriate solvents are given for each dye.
Characteristics of Ovonic Threshold Switches with Crystalline Semiconductor Electrodes
Authors: Henisch H. K. , Vendura G. J.
Published: January 2004

The letter describes asymmetric threshold-switching phenomena observed on thin films of Te40As37Ge7Si18 (0.2–1.9 μ), deposited by flash evaporation on crystalline Ge, and surface probed by means of a pyrolytic graphite counterelectrode. ``Dynamically tristable'' systems can be made in this way. The asymmetries are reversed for n- and p-type Ge. Suitably biased systems can be switched by illumination. The differences between the present results and those obtained on conventional threshold switches with two graphite electrodes call for an interpretation in terms of electronic-interface phenomena.
Photomechanical Effect in Noncentrosymmetric Semiconductors-CdS
Authors: Lagowski J. , Gatos H. C.
Published: January 2004

A new phenomenon is reported whereby illumination (in the visible spectrum) is converted into mechanical strain (elastic deformation or mechanical vibrations) in CdS wafers with an orientation perpendicular to the crystallographic axis [001]. It is believed that the light modulates the electric field at the surface (surface barrier) and causes an elastic strain due to the converse piezoelectric effect.
Differential Negative Resistance of n-Type Inversion Layer in Silicon MOS Field-Effect Transistor
Authors: Katayama Y. , Yoshida I. , Kotera N. , Komatsubara K. F.
Published: January 2004

A new type of voltage-controlled differential-negative-resistance effect was observed in an n-type surface inversion layer of a silicon MOS field-effect transistor with a very high mobility of 104 cm2/V sec at low temperatures.
Efficient GaAs–AlxGa1−xAs Double-Heterostructure Light Modulators
Authors: Reinhart F. K. , Miller B. I.
Published: January 2004

Properly designed GaAs–AlxGa1−xAs double heterostructures produce strong optical waveguides. The propagation constants of the waveguide modes can be readily modulated by the linear electro-optic effect. Measurements at a wavelength λ = 1.153 μm have yielded a phase modulation of 180° with -10 V applied bias to a device only 1 mm long. The power necessary to phase modulate light at λ ≈ 1 μm by 1 rad is of the order of 0.1 mW per 1-MHz band-width. The power dissipation is very strongly dependent on wavelength. At present, the high-frequency modulation is limited by the series resistance and capacitance of the device. The highest cutoff frequency determined thus far, ≈ 4 GHz, is considerably lower than that calculated based on the geometry and material properties.
Unidirectional Thin-Film Ring Laser
Authors: Ulrich R. , Weber H. P.
Published: January 2004

A light-guiding thin polyurethane film, doped with rhodamine 6G, is coated on the surface of a cylindrical glass rod and pumped with a pulsed Ne laser. A prism-film coupler produces two output beams corresponding to clockwise and counterclockwise oscillations around the circumference of the rod. Unidirectional operation is obtained when one of the output beams is reflected back into itself. A maximum directionality ratio of 17 was measured.
Excited-State Effects in Nonlinear Infrared Absorption by Ethylene
Authors: Ressler N. W. , Crain R. W.
Published: January 2004

This letter reports measurements of the intensity-dependent transmittance of ethylene near 949 cm−1. The qualitatively different behavior of transmittance for the CO2 laser lines P(12) and P(16), which are nearly symmetrically located on opposite sides of the ground-state resonance, is described in terms of a 3-level model with an anharmonic frequency shift in the excited-state resonance. The results are also compared to the predicted intensity-dependent transmittance for a 2-level model.
Parametric Image Upconversion of 10.6-μm Illuminated Objects
Authors: Chiou Walter C. , Pace Frank P.
Published: January 2004

Images at 0.96 μm of 10.6-μm illuminated objects were obtained by the parametric image upconversion technique. The nonlinear material used in this experiment was a single crystal of proustite pumped by 1.06-μm radiation from a single-mode Nd:YAG laser. Angular resolution of about 3 mrad and a 12-deg field of view were obtained. The upconverter was operated in a Fourier-space configuration and gave nearly diffraction-limited performance.
Amplitude-Dependent Shear Wave Attenuation near Tc in Rhenium
Authors: Robinson D. A. , Levy M.
Published: January 2004

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.
Observation of Two-Photon Conductivity in GaAs with Nanosecond and Picosecond Light Pulses
Authors: Jayaraman S. , Lee C. H.
Published: January 2004

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.
Radiation-Damage-Induced Apparent Optical Absorption Interpreted as Scattering from Defect Zones
Authors: Meek R. L. , Gibson W. M. , Maclennan C. G. , Maher D. M.
Published: January 2004

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
Authors: Bridges T. J. , Burkhardt E. G. , Smith P. W.
Published: January 2004

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.
Two-Phase Stepped Oxide CCD Shift Register Using Undercut Isolation
Authors: Berglund C. N. , Powell R. J. , Nicollian E. H. , Clemens J. T.
Published: January 2004

A novel technique for fabricating charge-coupled devices (CCD) is described. Effectively zero lateral spacing between adjacent capacitor plates of the CCD is achieved by taking advantage of the SiO2 undercutting which occurs during etching of the SiO2–Al2O3 double insulator system.
Surface Impedance of Thin Metal Films under Anomalous Skin Effect Conditions
Authors: Mayadas A. F. , Henry G. R. , Shatzkes M.
Published: January 2004

Exact numerical solutions for the surface impedance and electric field of metal films under anomalous skin effect conditions are presented and discussed. It is shown that under certain conditions the film impedance is significantly lower than the bulk impedance.
Vortex-Confined Pumping Discharge in Dye Laser Solution
Authors: Ferrar C. M.
Published: January 2004

Centrifugally formed vortex channels in dye laser solutiosn can provide damage-resistant confinement of intense capillary arc discharges and allow efficient coupling of arc radiation into the dye.
Effect of Oxygen on the Electromigration Behavior of Al Thin Films
Authors: Berenbaum L.
Published: January 2004

Aluminum thin films were electrically stressed in a high-vacuum furnace and the damage resulting from the electromigration of aluminum ions was monitored by the change in stripe resistance. When high-purity oxygen was periodically bled into the furnace, Ṙ ranged between a constant value and zero, depending on the magnitude of ΔR. The proposed model suggests the stabilization of microscopic voids by the formation of a thin oxide film on the void surface.
Sealed Room-Temperature CO–CO2 Laser Operating at 5 or 10 μ
Authors: Seguin H. J. , Tulip J. , White B.
Published: January 2004

A gas laser which oscillates on either the 5-μ CO or the 10-μ CO2 lines has been developed. The laser is sealed off, operates at room temperature, and has given over 4-W total power, alternatively at 5 and 10 μ. Preliminary results indicate that performance characteristics and lifetimes comparable with conventional CO2 lasers should be achievable.
Thermally Induced Negative Resistance in Si-Doped YIG
Authors: Kaplan Theodore , Bullock D. C. , Adler David , Epstein D. J.
Published: January 2004

A thermal model is presented to explain the recently observed current-controlled negative resistance in single crystals of Si-doped YIG. Steady-state I-V characteristics are calculated from electrical and thermal conductivity data and are compared with the observed curve. The agreement between theory and experiment is excellent.
Domains in SmCo5 at Low Temperatures
Authors: Westendorp F. F.
Published: January 2004

Domain spacing in SmCo5 is observed to increase by a factor of 1.5 at 78 K as compared with the spacing at room temperature. This indicates a difference in domain wall energy, which may explain the experimentally found difference in coercive force.
Superconducting Properties of Multifilamentary Nb3Sn Made by a New Process
Authors: Suenaga M. , Sampson W. B.
Published: January 2004

A new processing method for producing multifilamentary A-15 superconducting composite wires in a ductile matrix is described. Nb3Sn made in this way was found to have a critical temperature of 17.5 K and a critical current density of 7.5×105 A/cm2 at 40 kG when suitably heat treated. The composite conductor could be bent with a radius of 2 cm or greater without appreciable degradation of its current-carrying capacity.
Variable Ultrafast Photographic Shutter
Authors: Mourou G. , Drouin B. , Denariez-Roberge M. M.
Published: January 2004

We propose an ultrafast shutter, based on the saturable properties of polymethine cyanide dyes, with a variable shutter speed of 10–40 psec and more. With this, one can measure the pulse duration of the mode-locked ruby laser pulse. We can also deduce the fluorescence decay time of these solutions employed.
Optically Pumped Molecular Iodine Vapor-Phase Laser
Authors: Byer R. L. , Herbst R. L. , Kildal H. , Levenson M. D.
Published: January 2004

We have observed stimulated emission in optically pumped molecular iodine vapor. Laser action occurs in more than 150 individual lines which span the spectral region from 544 to 1.335 nm for excitation by the 530-nm second-harmonic wavelength of a Q-switched Nd:YAG laser. The iodine laser oscillates for input pulse energies of a few microjoules. Approximately 106 individual laser transitions may be excited by various pump frequencies.
Study of Film Thickness in rf Sputtering
Authors: Ratinen H.
Published: January 2004

The thickness of copper films prepared by the rf-sputtering technique has been studied by changing the argon gas pressure and the distance between the target and the substrate. Glass disks with 110-mm diameters were used as substrates. The relative thickness of a film was tested by using a laser beam. The distribution of copper was observed to be centralized as the argon gas pressure was lowered or the distance between the target and the substrate shortened. By using a proper arrangement, the film obtained was smooth enough for optical purposes.
Suppression of Spurious Triple-Transit Signals in Acoustic Surface-Wave Delay Lines
Authors: Wauk M. T.
Published: January 2004

Spurious triple-transit signals can be rejected through phase cancellation by rotation of one transducer with respect to the other or by use of a triangular-shaped metal film in the path between parallel transducers. Rejection is facilitated by slightly limiting the aperture via mechanical surface loading. The technique is demonstrated to give high triple-transit suppression in delay lines with 20-electrode-pair transducers that give specular acoustic reflections. The technique is not found to be useful for conjugate-matched 5-electrode-pair transducers, which are shown to give acoustic reflections normal to the electrodes.
Holography and Holographic Interferometry with Pulsed High-Power Infrared Lasers
Authors: Decker G. , Herold H. , Röhr H.
Published: January 2004

Holograms are produced on bismuth and paraffin films with pulsed TEA CO2 laser light. Sensitivity of both films is about 0.3 J/cm2. Local resolution proved to be much better than 70 lines/mm. Capability of this holographic technique for interferometric measurements is demonstrated.
High-Pressure Pulsed CO2 Chemical Transfer Laser
Authors: Poehler T. O. , Shandor M. , Walker R. E.
Published: January 2004

The exothermic chain reactions between deuterium and fluorine have been used to produce intense laser emission from carbon dioxide in a high-pressure pulsed transfer laser. Stable mixtures of D2–F2–CO2 diluted in He and cooled to −60°C were used as a fuel. Reactions initiated by flash photolysis of this system produced 10.6-μm radiation with peak power of 200 kW and total energy of 5 J in dilute mixtures at total pressures up to 1 atm. The output power, laser pulse duration, and time of maximum gain are found to be strongly dependent on partial pressures of the constituents, total pressure of reactive components, nature of the diluents, and degree of refrigeration of the mixture.
Tunable GaAs Laser in an External Dispersive Cavity
Authors: Ludeke R. , Harris E. P.
Published: January 2004

Tunability of the cw radiation from a GaAs injection laser in an external dispersive cavity was achieved over a range of 150 Å about a center wavelength of 8525 Å at 77°K. The emitted radiation was analyzed with a Fabry-Perot etalon. Under certain conditions single-mode operation with cw output power as large as 17 mW was observed. Half-width of such modes was estimated to be less than 350 MHz.
cw Laser Action on 31 Transitions in Tellurium Vapor
Authors: Silfvast W. T. , Klein M. B.
Published: January 2004

We have observed 31 cw laser transitions in the spectrum of singly ionized Te II, ranging in wavelength from 4843 to 9378 Å. 16 transitions were observed with He as a buffer gas, and 20 transitions were observed with Ne (5 were common to both gases). The experimental evidence indicates that charge transfer is the dominant excitation mechanism for both gases.
CO2 Waveguide Gas Laser
Authors: Jensen Richard E. , Tobin Mary S.
Published: January 2004

The characteristics of a CO2 waveguide gas laser are described. An output power of 2.5 W was obtained from a discharge tube having a 23.7-cm length and a 3.3-mm diameter. The output mode pattern was very stable and insensitive to disturbances of the resonator and indicates the laser output is predominantly the EH11 waveguide mode. The power output was sensitive to mirror position, and maximum power was obtained when the centers of curvature of the mirrors were a few centimeters inside the waveguide.
Nonlinear Forward Drift of Electrons in a Laser Beam
Authors: Lieu O. S. , Shin E. E. H.
Published: January 2004

Electrons interacting with laser radiation acquire a nonlinear drift velocity vD = e2E02/2m2cω2 in the forward longitudinal direction, thus giving rise to a dc current. Although its magnitude is too small to contribute to the ``heating'' of electrons, it may nevertheless prove useful in a laser-operated solid-state device using a low-effective-mass semiconductor.
Significance of Electric Fields on the Growth of Thin Metal Films
Authors: Murr L. E. , Singh H. P.
Published: January 2004

Thin films of Au, Ag, Pt, Pd, In, Sn, Bi, and Te were vacuum vapor deposited onto air-cleaved NaCl (001) substrates in the absence of an electric field and in the presence of dc fields (in the plane of the substrate), ranging in intensity from 10 to 103 V/cm. The vacuum environments were varied between 10−6 and 10−9 Torr, and evaporation rates ranged from 10 to 103 Å/sec. Substrate temperatures were varied from 25 to 350°C for a distribution of mean film thicknesses ranging from 15 to 1200 Å. No significant effects of an electric field applied in the plane of the substrate were observed upon examination and comparison of representative film samples by transmission and scanning electron microscopy.
Tunneling Measurements of the Superconducting Energy Gap of Bulk Polycrystalline Indium
Authors: Averill R. F. , Straus L. S. , Gregory W. D.
Published: January 2004

A successful new technique for the fabrication of bulk indium tunnel junctions, In (bulk) - Al2O3–Pb, has been developed and was used to determine the value of the reduced energy gap as 2Δ(0) /kTc = 3.58 for bulk polycrystalline indium.
Atmospheric-Pressure Pulsed Chemical Laser
Authors: Wilson J. , Stephenson J. S.
Published: January 2004

A pulsed chemical laser using the reaction between fluorine and hydrogen or deuterium is described. The reactants are mixed at a pressure which is above the second explosion limit, and reaction is initiated by photolytic dissociation of the fluorine. Laser pulse energies of 96 mJ were achieved from hydrogen fluoride, and 350 mJ from carbon dioxide which acquires vibrational energy by transfer from deuterium fluoride. These pulse energies are lower than expected theoretically.
Optical-Waveguide Mode-Conversion Experiments
Authors: Shah Manhar , Crow John D. , Wang Shyh
Published: January 2004

The results of two experiments utilizing crystalline quartz as the substrate of a thin-film optical waveguide are presented. TE ⇌ TM mode conversion is demonstrated and shown to be due to the anisotropic nature of quartz. Using experimentally measured parameters in the previously reported analysis, we find good agreement between the theory and experiment.
Comment on ``0.2-W Repetitively Pulsed Flashlamp-Pumped Dye Laser''
Authors: Schmidt W. , Wittekindt N.
Published: January 2004

Average output powers of 3.5 W (broadband emission, 890-W pumping power) and 0.2 W (bandwidth 1.5×10−2 Å, 250-W pumping power) were obtained from repetitively pulsed flashlamp-pumped rhodamine 6G lasers.
Effects of Al Films on Ion-Implanted Si
Authors: Lee D. H. , Hart R. R. , Marsh O. J.
Published: January 2004

Ion-implanted amorphous regions of Si in the presence of Al films 300–700 Å thick are found to recrystallize between 325 and 350°C. This recrystallization occurs at a temperature significantly below both the epitaxial regrowth of the amorphous Si (∼ 600°C) and the Al–Si eutectic of 577°C. In the case of the 300-Å metallizations, the enhanced low-temperature reordering of the damaged layer is simultaneously accompanied by an interfacial migration which results in Si transport to the surface of the sample. The observed phenomena are analyzed as a function of anneal temperature by 280-keV α-particle backscattering and 1.8–6.2-eV optical reflectance measurements.
Enhanced Migration of Implanted Sb and In in Si Covered with Evaporated Al
Authors: Hart R. R. , Lee D. H. , Marsh O. J.
Published: January 2004

Amorphous layers of Si produced by the bombardment of Sb+ and In+ and covered with ∼400 Å of Al show pronounced migration of the implanted atoms to the Si–Al interface and the Al surface after a 350°C anneal. This enhanced migration occurs simultaneously with the recrystallization of the amorphous layer. Low-temperature migration effects are not seen in uncoated amorphous Si, nor on reordered Si covered with evaporated Al. The depth distribution of the implanted atoms is measured by backscattering analysis with 280-keV α particles.
Electrical Control of Fixation and Erasure of Holographic Patterns in Ferroelectric Materials
Authors: Micheron F. , Bismuth G.
Published: January 2004

We have demonstrated that fixation and erasure of phase holograms in ferroelectric materials can be achieved by fast electrical control. High ionic mobility that allows the change of the electronic pattern into a stable ionic one is obtained by applying, during 0.1 sec, an external field slightly smaller than the coercive field to the crystal. Erasure is accomplished in 3 sec by applying a field that causes saturation of the polarization. Investigation of this process was carried out in BaTio3 crystals doped with Fe.
Investigation of Lithium Precipitation in Germanium Crystals by X-Ray Transmission Topography
Authors: de Kock A.J.R. , Beeftink F.M. , Schell K.J.
Published: January 2004

Lithium precipitation in Czochralski-grown germanium crystals is investigated by x-ray transmission topography. Precipitation on dislocations is detected. Striated distributions of precipitates in dislocation-free crystals are attributed to lithium nucleation on vacancy clusters.
Laser-Triggered Avalanche-Transistor Voltage Generator for a Picosecond Streak Camera
Authors: Thomas S. W. , Coleman L. W.
Published: January 2004

Direct optical triggering of an avalanche transistor with a short laser pulse has been demonstrated. In some applications this system provides a compact low-jitter replacement for a laser-triggered spark gap. The technique has been applied to generating the gating and sweep voltages in a picosecond streak camera for laser pulse diagnostics where it eliminates the need for multiple beam splitters and long delays. The ``trigger'' avalanche transistor was placed as one of a series string of avalanche transistors. A portion of the switched-out laser pulse to be diagnosed was focused onto the trigger transistor chip. Nanosecond-rise kilovolt waveforms are thus generated with time jitter of the entire system being less than 100 psec.
Optically Pumped Room-Temperature InxGa1−xAs Lasers
Authors: Rossi J. A. , Chinn S. R. , Mooradian A.
Published: January 2004

Several compositions of InxGa1−xAs have been operated as optically pumped lasers at room temperature. Coherent emission has been observed out to 1.12 μm, corresponding to an alloy composition of x ≃ 0.20. Typical total-power-conversion efficiencies are measured to be 0.6%.
Ion-Channeling Studies of Epitaxial Layers
Authors: Picraux S. T.
Published: January 2004

Depth and temperature dependences of ion channeling were used to characterize 1–4-μm Si layers on spinel substrates (Al2O3 · MgO). Profiles of the density of crystal imperfections in the Si layers have been calculated from the channeling spectra. The imperfections are greatest near the interface, and the crystalline quality improves significantly with increasing distance from the interface. This technique is particularly applicable to heteroepitaxial layers containing high densities of crystal imperfections and can be used to monitor the relative influence of growth parameters on the crystalline quality of the layers.
Transport and Structural Properties of VO2 Films
Authors: Kwan Clarence C.Y. , Griffiths C.H. , Eastwood H.K.
Published: January 2004

Transport properties of sputtered VO2 films are shown to be critically dependent on the defect structure of this material. Measured values of thermoelectric power and Hall mobility for films deposited under optimum conditions are comparable to those previously measured on single crystals.
Electron Kinetic Processes in CO Lasers
Authors: Nighan William L.
Published: January 2004

Electron-energy distributions have been determined for electrically excited CO laser mixtures by numerically solving the Boltzmann equation for conditions typical of electric discharges. Solution of the electron-energy-conservation equation using the computed distribution functions reveals that vibrational and electronic excitation of CO, N2, and Xe dominates electron-energy-exchange processes for average electron energy in the 1–2-eV range characteristic of electric discharge conditions. For typical mixtures and discharge conditions, between 30 and 90% of the total electrical power is transferred to CO vibrational levels by direct electron excitation, a result consistent with the high electrical-optical conversion efficiency of electrically excited CO lasers. In addition, these calculations illuminate the influence of Xe, N2, and vibrationally excited molecules, as regards electron collision processes in CO laser discharges.
Acceptor State of Gold in Silicon—Resolution of an Anomaly
Authors: Parrillo Louis C. , Johnson Walter C.
Published: January 2004

We propose that a severe anomaly among the parameters of the gold acceptor state in silicon can be resolved by taking into account the temperature dependence of all the parameters. The temperature variation of most consequence is that of the trap energy level with respect to the band edges. We show that if the trap maintains a constant relative position in the gap, the resulting corrections to the activation energies place the trap nearly 0.1 eV higher in the gap at 300°K than was supposed, and all of the available data are brought into agreement.
Enhanced Annealing Effects in Boron-Implanted Layers in Silicon by Postimplantation of Silicon Ions
Authors: Bauer L. -O.
Published: January 2004

Various effects of postimplantation of silicon ions on boron-implanted layers are reported. The amount of enhanced annealing depends critically on the target temperature during implantation and on the dose of silicon ions used. At 100 keV, a 5×1015/cm2 silicon dose is necessary to create an amorphous layer extending up to the surface at room temperature. Close to 100% of the boron ions located in this layer become electrically active after annealing at 600°C. For boron doses approximately greater than 3×1015/cm2, shallow silicon implantations produce stronger enhanced annealing than expected. For boron doses less than 2×1014/cm2, little or no enhanced annealing is observed.
Mode-Selection Technique for Continuously Pumped Repetitively Q-Switched Lasers
Authors: Ammann E. O. , Yarborough J. M.
Published: January 2004

A mode-selection technique is described which applies specifically to continuously pumped repetitively Q-switched lasers. The technique is based on opening the Q switch just as the laser gain exceeds the Q-switch hold-off loss. This results in a reduction of the number of both longitudinal and transverse modes present in the Q-switched output. Of particular interest is the simplicity and convenience of this scheme, since it does not require the introduction of any components inside the laser cavity. Experimental data are presented on a continuously pumped repetitively Q-switched Nd: YAlO3 laser.
Kinetic Cooling of a Gas by Absorption of CO2 Laser Radiation
Authors: Gebhardt Frederick G. , Smith David C.
Published: January 2004

The effect of kinetic cooling due to the absorption of 10.6-μ CO2 laser radiation in the atmosphere has recently been predicted. In this letter, experimental evidence for this effect is presented. Transient-density increases due to the kinetic cooling have been observed in CO2–N2 mixtures following the propagation of an ∼ 1-μsec 0.5-J CO2 laser pulse through the gas. The experiments were performed with varying concentrations of CO2 and the observed cooling and subsequent heating effects are explained using the usual three-level approximation for vibrational-energy transfer in CO2–N2, together with known relaxation rates.
Nonlinear Optical Properties of Ferroelectric Lead Titanate
Authors: Singh S. , Remeika J. P. , Potopowicz J. R.
Published: January 2004

Optical transmission, refractive-index, and nonlinear optical properties of single domain PbTiO3 have been measured between room temperature and the Curie temperature Tc. The second-harmonic coefficient d31 is found to be the highest for any room-temperature ferroelectric. Since the birefringence is small (approximately 0.008), phase-matched SHG is not possible, but nondegenerate three-frequency mixing should be possible. The Miller δ coefficients are analyzed in terms of Jerphagnon's formulation and poor agreement is observed.
Light-Guiding Structures of Photoresist Films
Authors: Weber H. W. , Ulrich R. , Chandross E. A. , Tomlinson W. J.
Published: January 2004

We have made light-guiding thin films with losses of ∼ 2.2 dB/cm at 0.633 μm from Kodak KPR photoresist which has been processed to remove a photosensitizer which absorbs in the visible. Curved and straight optical strip guides as narrow as 5 μm have been written in these films and have shown light guiding with losses of 3 to 8 dB/cm at 0.633 μm.
Time Dependence of Charge Transport in MIS Memory Transistors
Authors: Ferris-Prabhu A. V.
Published: January 2004

Based on the direct tunneling model, the complete solution is obtained for the charge-transport equation for MIS memory transistors. It is shown that the time dependence is linear in the microsecond range, roughly logarithmic in the millisecond range, and eventually saturates to a value determined by the physical characteristics of the device. For an oxide layer 20 Å thick, the theory predicts a switching time of about 45 μsec and saturation in about 150 sec.
Acoustic-Wave Detection via a Piezoelectric Field-Effect Transducer
Authors: Greeneich E. W. , Muller R. S.
Published: January 2004

An oriented piezoelectric film has been incorporated in the insulator region of a silicon insulated-gate field-effect transistor to provide a sensitive high-frequency strain transducer. With this device, strains as low as 10−8 have been detected and gauge factors of roughly 7000 have been attained for applied ac strains at 5.6 MHz.
Use of an Electron Flood Gun to Reduce Surface Charging in X-Ray Photoelectron Spectroscopy
Authors: Huchital D. A. , McKeon R. T.
Published: January 2004

A flood-gun arrangement is shown to be useful in alleviating the sample-charging problem in x-ray photoelectron spectroscopy. Modest currents (<10−8 A) of low-energy electrons result in the shifting of photoelectron energy peaks to the proper positions and the reduction of the peak widths.
Minority-Carrier Sweepout in 0.09-eV HgCdTe
Authors: Emmons S. P. , Ashley K. L.
Published: January 2004

High-field measurements of decreased response time, gain saturation, and enhanced signal-to-noise ratio are reported as evidence of minority-carrier sweepout in 0.09-eV HgCdTe photoconductors.
Scattering-Mode Ferroelectric-Photoconductor Image Storage and Display Devices
Authors: Smith W. D. , Land C. E.
Published: January 2004

A new type of image storage and display device is described in which the image is stored by means of a longitudinal electro-optic scattering effect in ferroelectric ceramics. The stored image can be viewed directly or projected onto a viewing screen by using transmitted or reflected, polarized or unpolarized, white or monochromatic light. The device has the capability of selective erasure of part or all of the stored image.
Coating, Mechanical Constraints, and Pressure Effects on Electromigration
Authors: Ainslie N. G. , d'Heurle F. M. , Wells O. C.
Published: January 2004

The effect of the mechanical constraints exerted by coatings upon electromigration in thin films is evaluated on the basis of known pressure effects upon diffusion.