bluuebunny/crossref_metadata_2025 huggingface dataset:
USE OF CHARACTERISTIC X RAYS TO MONITOR ANNEALING OF ION-IMPLANTED DIAMOND
Authors: Davidson L. A. , Gibbons James F. , Der R. C. , Kavanagh T. M. , Khan J. M.
Published: January 2004

Bombardment of aligned type-IIa diamond substrates with 80-keV protons and simultaneous detection of the resulting characteristic carbon K x rays has revealed excellent channeling structure. This technique has been used to monitor the crystallinity of a surface implanted with P31+ ions. Crystallinity was destroyed by P31+ does of the order of 1014/cm2. Vacuum annealing at 950°C restored the diamond cubic crystal structure.
ACOUSTIC SURFACE WAVE MIXING ON α-QUARTZ
Authors: Lean E. G. H. , Powell C. G. , Kuhn L.
Published: January 2004

Experimental demonstration of the sum and difference frequency generation of surface acoustic waves on α-quartz is reported. Individually calibrated interdigital transducers were used to generate and detect the waves. The absolute level of the nonlinearly generated acoustic power was measured for various interaction lengths and found to agree with a theory based on nonlinear coupled amplitude equations.
NONLINEAR EFFECTS OF LASER PROPAGATION IN DENSE PLASMAS
Authors: Kaw Predhiman
Published: January 2004

Two nonlinear effects of laser propagation in dense plasmas have been analytically investigated, viz., laser penetration into an overdense plasma and the self-focusing of a laser beam. It is concluded that for laser powers currently being used, both these effects can be quite important.
COMMENTS ON ``LOW-FREQUENCY CURRENT FLUCTUATIONS IN A GaAs GUNN DIODE''
Authors: Shoji M. , D'Alessio F. J. , Kurokawa K.
Published: January 2004

Our measurements of the small signal conductance of a GaAs Gunn diode at low field values do not show the frequency dependence reported by K. Matsuno.
THE ACOUSTOELECTRIC VOLTAGE GENERATED IN CADMIUM SULPHIDE BY A NARROW INPUT ACOUSTIC SIGNAL
Authors: Larner D. J.
Published: January 2004

A theoretical application of the Weinreich relationship is presented which is valid for an acoustic signal of duration less than its transit time through the medium. The acoustoelectric field produced by a piezoelectrically active acoustic wave propagating through cadmium sulphide is calculated, and excellent agreement is demonstrated between experiment and theory with the crystal both amplifying and attenuating.
NEW cw METAL-VAPOR LASER TRANSITIONS IN Cd, Sn, AND Zn
Authors: Silfvast W. T.
Published: January 2004

cw laser action has been observed at 3250 Å in Cd II, 6453 and 6844 Å in Sn II, and 7479 and 7588 Å in Zn II. Laser action occurred in He-metal-vapor discharges at pressures of several Torr He and much lower partial pressures of the metal vapor. The first four transitions have similar operating characteristics and are believed to be excited by Penning collisions between metastable He atoms and neutral metal-vapor atoms (similar to the mechanism for exciting the 4416 Å cw transition in Cd II). The 3250 Å transition is the first cw uv laser that can be built and operated with relatively simple techniques, similar to those used in He–Ne lasers.
RESONANTLY SUSTAINED BOUNDED RADIOFREQUENCY PLASMA IN A SPHERICAL CAVITY
Authors: Messiaen A. M. , Vandenplas P. E.
Published: January 2004

It is shown that the low-power linear behavior of a cavity (here a spherical one) partially filled with plasma plays a fundamental role in understanding the formation of an rf plasma inside it at higher power levels. The rf plasma is found to be sustained in one of the linear resonant states of the system. With moderate rf power (10–100 w), it is possible to sustain bounded plasmas in the cavity having densities far above the critical one. The value of the density depends, as is theoretically predicted, essentially on the frequency and only slightly on the power level of the exciting signal.
EFFECTS OF CONTACTS ON THE EMISSION FROM INDIUM ANTIMONIDE
Authors: George E. V. , Bekefi G.
Published: January 2004

The low-field microwave emission from InSb subjected to parallel electric and magnetic fields is strongly dependent on the type of electrical contact attached to the sample. It is suggested that the radiation is a localized phenomenon due to high-field regions or due to a Schottky barrier.
ELECTRON TEMPERATURE AND DENSITY IN ARGON ION LASER DISCHARGES
Authors: Zarowin C. B.
Published: January 2004

Kinetic theory is used to calculate the electron temperature and drift velocity in a continuous argon ion laser discharge. The calculated electron mean energies range from 1.0–7.5 eV, increasing with current density to the ⅔ power. The calculated drift velocities range from ∼1–25 × 106 cm/sec. From these parameters, the electron density is obtained at typical current densities: At 500 A/cm2 the electron density is found to substantially exceed 1015 cm−3. Some consequences of these drift velocities and densities are discussed.
SIMULTANEOUS MODE-LOCKING AND SECOND-HARMONIC GENERATION BY THE SAME NONLINEAR CRYSTAL
Authors: Gurski T. R.
Published: January 2004

Simultaneous mode-locking and quasi cw second-harmonic generation (SHG) in high-temperature lithium niobate or barium sodium niobate of a Nd3+:YAG laser have been accomplished by electro-optic modulation of the nonlinear medium. This technique will be useful for obtaining ``100% conversion efficiencies,'' which would not be possible by the standard intracavity method, with nonlinear crystals that are either too short or have too low a nonlinear coefficient to achieve optimum coupling of the laser.
DIRECT OBSERVATION OF THE MULTIPLICITY OF IMPURITY CHARGE STATES IN SEMICONDUCTORS FROM LOW-TEMPERATURE HIGH-FREQUENCY PHOTOCAPACITANCE
Authors: Sah C. T. , Rosier L. L. , Forbes L.
Published: January 2004

A simple method is proposed and demonstrated which provides a direct and reliable observation of the multiplicity of charge states of impurity centers. This is achieved by recording the high-frequency photocapacitance changes in a reverse-biased p-n junction at a low temperature during monochromatic illuminations at different wavelengths. The photon energy is first chosen so that it is above the threshold required to excite one of the trapped electrons at the impurity center, but below the threshold of exciting the next electron. After the capacitance change is completed, the photon energy is increased to the next range to excite the second trapped electron into the conduction band. The equality of the change of the squared capacitance during these two illumination periods then implies a multiplicity of three of the charge state. The procedure may be repeated for more than three charge states. An example is given for a sulfur-doped silicon p + n junction whose double donor levels have thermal activation energies of 0.30 and 0.55 eV below the conduction-band edge.
DIFFUSIVITY OF ELECTRONS AND HOLES IN SILICON
Authors: Sigmon T. W. , Gibbons J. F.
Published: January 2004

The variation of electron and hole diffusivity and drift velocity in the ``warm electron'' range of electric field (1–50 kV/cm) has been measured for 〈111〉-oriented silicon at 300°K. These measurements were obtained from the transient currents produced from a thin layer of electrons or holes propagating through the high-field region of a reverse-biased p+−ν−n+ diode. Use of a sampling oscilloscope in conjunction with an analog-to-digital converter and averaging system resulted in significant improvement of the resolution and statistics of the measurement and allowed digital readout of the resulting data. Diffusivity of both electrons and holes was found to decrease slightly below the low-field values in the electric field range of 6–50 kV/cm. Drift velocity versus electric field was measured and found to be reasonably consistent with the literature.
``MEMORY EXCHANGE'' IN AMORPHOUS SEMICONDUCTORS
Authors: Kikuchi M. , Iizima S.
Published: January 2004

Experimental observations of the interaction of the memory in amorphous semiconductors are described. Between two pairs of electrodes located sufficiently close by, memory exchange has been observed, namely, switch-on or ``lock-on'' (memory setting) of one pair of electrodes unlocks the memory of the other pair. The results are attributed to the thermal interaction between ``lock-on'' filament and switch-on filament.
ELECTRONICALLY TUNABLE ACOUSTO-OPTIC FILTER
Authors: Harris S. E. , Nieh S. T. K. , Winslow D. K.
Published: January 2004

Experimental results on a new type of electronically tunable optical filter are described. Tuning from 7000 to 5500 Å has been obtained by changing an acoustic driving frequency from 750 to 1050 MHz. A band pass of less than 2 Å, a corrected peak transmission of 50%, and an average skirt rejection ratio of about 45 dB have been obtained.
SUPERCONDUCTING PROPERTIES OF NIOBIUM-TITANIUM-NITRIDE THIN FILMS
Authors: Gavaler J. R. , Deis D. W. , Hulm J. K. , Jones C. K.
Published: January 2004

A series of Nb–Ti–N films have been prepared, with various Nb/Ti ratios, by a high purity, reactive sputtering process. A maximum in transition temperature (at ∼ 15.5°K) has been obtained for a composition of Nb0.5Ti0.5N. Critical field and critical current measurements indicate a degradation in these properties with increasing titanium content, contrary to results reported previously.
MEASUREMENT OF IRON DIFFUSION IN AN Fe-3% Si ALLOY BY MEANS OF THE MÖSSBAUER TECHNIQUE
Authors: Lewis Sanford J. , Flinn Paul A.
Published: January 2004

Iron diffusion in an Fe-3% Si alloy has been studied by means of the Mössbauer effect. The results in this iron-base system agree closely with conventional measurements and do not appear to exhibit the factor of 2 anomaly with the Singwi and Sjölander analysis which Knauer and Mullen observed for iron in dilute solution. The values obtained can be described by the equation D=0.20(−0.15;+0.65) exp[−49 600±3700/RT].
ANOMALOUS DIFFUSION AND RESISTIVITY OF A TURBULENT, WEAKLY IONIZED PLASMA
Authors: Garosi G. A. , Bekefi G. , Schulz Michael
Published: January 2004

The plasma loss rate and certain transport coefficients of a dc discharge in the presence of turbulent argon-gas flow are found to vary strongly with Reynolds number (Re). The loss rate increases by a factor of 15 as Re is increased from zero to 6300.
A NEW MEASUREMENT OF THE VELOCITY-FIELD CHARACTERISTIC OF GaAs
Authors: Fay B. , Kino G. S.
Published: January 2004

The velocity-field characteristic for electrons in GaAs has been measured in the negative differential mobility region between 4.5 and 11 kV/cm by a new direct method involving probe measurements on the surface of a bulk GaAs two-port amplifier. The measurements were taken on GaAs of resistivity in the 500–1000 Ω-cm range.
AN OPTICAL IMAGING METHOD FOR DIRECT OBSERVATION AND STUDY OF ACOUSTIC SURFACE WAVES
Authors: Soffer B. H. , Close D. H. , Pedinoff M. E.
Published: January 2004

An optical-spatial filtering technique for studying complex, high frequency, standing and traveling acoustic surface waves is described. The relative amplitude distribution is directly displayed, and the wavelength and velocity are accurately measured. The velocity for z propagation on a y-cut LiNbO3 crystal is found to be 3472.5 ± 1.5 m-sec−1.
CZOCHRALSKI GROWTH AND PROPERTIES OF YAlO3 LASER CRYSTALS
Authors: Weber M. J. , Bass M. , Andringa K. , Monchamp R. R. , Comperchio E.
Published: January 2004

Czochralski growth characteristics of a new laser host crystal, YAlO3, and measurements of its optical, thermal, and mechanical properties are reported. Stimulated emission from Nd3+ in YAlO3 has been observed.
CONTINUOUS, COHERENT OSCILLATION IN n-InSb
Authors: Tacano Munecazu , Kataoka Shoei
Published: January 2004

Detailed measurements of the oscillation frequencies in n-InSb at 77°K as a function of dc sample current and magnetic field are described. These show the existence of two modes of instabilities, which are in the ranges of 0.2 to 0.8 GHz and of a few to several tens of MHz, respectively.
MODULATION OF AN ELECTRON WAVE BY A LIGHT WAVE
Authors: Schwarz Helmut , Hora H.
Published: January 2004

Electron transmission diffraction patterns of thin monocrystal films are made visible on a nonluminescent target, if the films are illuminated by a 107 Wcm−2 argon laser irradiation. It appears that the 50-keV electrons pick up an oscillation of the light frequency within the crystal film and preserve this oscillation state until they reach the nonluminescent target.
LIGHT MODULATION BY MEANS OF THE STARK EFFECT IN MOLECULAR GASES—APPLICATION TO CO2 LASERS
Authors: Landman Alfred , Marantz Howard , Early Vincent
Published: January 2004

The molecular Stark effect in gases may be used to modify the output of lasers in a systematic fashion, and may therefore be used as the basic constituent in a modulator element to control a laser beam. Experimental data for various CO2 laser lines and a number of electro-optic gases external to the laser cavity show amplitude modulation up to 20% for about 25% absorption and electric fields of the order of 1 kV/cm.
CATAPHORETIC SEGREGATION PROCESSES IN KRYPTON-XENON MIXTURE
Authors: Bhattacharya A. K.
Published: January 2004

Direct evidence of the cataphoretic segregation of small amounts of xenon in krypton is presented. The phenomenon of cataphoresis in Kr–Xe mixtures is explained on the basis of ionic reactions.
AMPLIFICATION OF GUIDED ELASTIC WAVES IN PIEZOELECTRIC PLATES THROUGH ELECTRICAL COUPLING TO A SEMICONDUCTOR
Authors: Fischler C. , Yando S.
Published: January 2004

Guided elastic waves in lead zirconate—titanate (PZT) and lithium niobate plates can be amplified acoustoelectrically by choosing the proper plate orientation and capacitively coupling the piezoelectric field into an adjacent semiconductor. To date, amplification has been observed for the first three flexural modes and the zero longitudinal and shear horizontal modes in PZT, as well as the first flexural and zero shear horizontal modes in lithium niobate. The strongest effect was found near the cutoff frequency of the F1 mode, with electronic gains in excess of 40 dB/cm at 4 MHz in PZT coupled to a plate of n-type silicon.
VISIBLE-LIGHT EMITTING DIODES USING (II–VI)-(III–V) SYSTEMS
Authors: Robinson Robert J. , Kun Zoltan K.
Published: January 2004

Room-temperature visible-light emitting diodes were made using liquid phase epitaxy. The n-side of the junction was ZnSe or ZnSxSe1−x. It also served as the substrate. A layer of the II–VI compound with small III–V compound addition formed the p-side of the junction. The current-voltage characteristics, color, and geometry of the emitting area indicated that the visible emission was produced by injecting holes into the n-side. Efficiency has not yet been measured; it appears to be low but is improving as techniques are being perfected.
MAGNETOELASTIC LOVE WAVES
Authors: Matthews H. , van de Vaart H.
Published: January 2004

Magnetostatic surface waves are coupled to Love waves when the substrate is magnetoelastic. The coupling causes a nonreciprocal splitting of the Love wave spectrum.
BISTABLE OPTICAL ELEMENT AND ITS APPLICATIONS
Authors: Szöke A. , Daneu V. , Goldhar J. , Kurnit N. A.
Published: January 2004

Optical resonators containing saturable absorbers (saturable resonators) have nonlinear characteristics and can exhibit hysteresis. This is demonstrated experimentally at 10.6 μ wavelength. A saturable resonator is used to switch out the CO2 laser light from its cavity and for repetitive Q-switching. Devices are described to obtain variable length pulses, infinite pulse trains, logical operations on two signals, and memory functions.
AVALANCHE MULTIPLICATION IN BULK n-Si
Authors: Dalal Vikram L.
Published: January 2004

The avalanche coefficient of electrons α has been measured in bulk n-Si for the first time. The measured values of α fit the theoretical curves of Baraff with εg < εi < 1.5 εg and 60 < λ < 80 A, where εi is the ionization energy and λ is the phonon mean-free path. The values of α agree with the extrapolated values from the p-n junction data of Lee, et al., but disagree with the results of Ogawa.
CHANNEL PLATE IMAGE CONVERTER IN ARGON FIELD-ION MICROSCOPY
Authors: Lewis R. , Gomer R.
Published: January 2004

A field-ion microscope utilizing an internal channel plate ion-to-electron converter is described and some results with He and Ar are presented. The device is shown to have excellent resolution, and a gain of ∼ 103 for He and ∼ 102 for Ar, relative to unintensified He micrographs. Good imaging of clean W surfaces can be achieved at 2 V/Å by using ultrapure Ar and ultrahigh vacuum; Ar imaging of adsorbed impurities occurs at 1.7 V/Å.
PSEUDO-KIKUCHI PATTERN DEGRADATION BY A THIN AMORPHOUS SILICON FILM
Authors: Wolf E. D. , Braunstein M. , Braunstein A. I.
Published: January 2004

Measurements are reported which show that a few tens of angstroms of an amorphous adlayer of silicon on a single-crystal (111) silicon surface produces a measurable degradation in the pseudo-Kikuchi backscattered electron pattern of this surface. Normalized pattern quality, as defined in this work, is shown to decrease rapidly with adlayer film thickness and to become effectively zero at 350 Å for a primary electron beam accelerating voltage of 21.3 kV. At 5 kV, the normalized pattern quality was effectively zero for all measurable film thicknesses (thickness measurement limit was ∼20 ± 20 Å).
BREAKDOWN CHARACTERISTICS OF AlxGa1−xAs AVALANCHE DIODES
Authors: Yeh C. , Liu S. G.
Published: January 2004

The breakdown voltage and the maximum electric field of AlxGa1−xAs avalanche diodes are presented as a function of the aluminum content in the samples. Aluminum content is estimated from the actual weight ratio of Al and Ga and the band gap energy of the samples. The maximum electric fields are calculated from the measured data of the breakdown voltage, capacitance at breakdown, and diode dimensions. Experimental results indicate that in addition to its function of increasing the band gap energy, increased Al contents also reduce the impurity gradient of the diodes. As a result, the breakdown voltage is found to increase more rapidly than the maximum electric field, when the Al content is increased. Values of maximum electric field in the range from 6 to 8 × 105 V/cm are observed. These values compare favorably with those of GaAs and GaP.
OPTICAL THIRD HARMONIC GENERATION USING MODE-LOCKED AND NONMODE-LOCKED LASERS
Authors: Wang Charles C. , Baardsen E. L.
Published: January 2004

Optical third harmonic generation in ADP crystals has been studied both in reflection and along the phase-matched direction. Results with a mode-locked laser indicate that only a small fraction (∼4%) of the total energy per laser shot was associated with the picosecond spikes in the laser output. This suggests that the peak power associated with the picosecond pulses may have been grossly overestimated in some cases.
A SUPERSONIC MIXING CHEMICAL LASER
Authors: Airey J. R. , McKay S. F.
Published: January 2004

The reaction F + HCl → HF† + Cl has been used to produce cw chemical laser action. This has been accomplished by mixing two supersonic streams of the reactant species in a shock tunnel. The time duration of the laser action is two orders of magnitude longer than the natural laser pulse in a non-flowing system, i.e., it is limited only by the flow time of the shock tunnel.
ACOUSTIC SURFACE WAVES ON SILICON
Authors: Pratt R. G. , Lim T. C.
Published: January 2004

Acoustic surface wave phase velocities have been measured on (001), (110), and (111) surfaces of single-crystal silicon using the wedge method. Good agreement between the theoretical and experimental results was obtained.
ELECTRO-OPTIC EFFECT AND MODULATED INTERFERENCE IN TANTALUM OXIDE FILMS
Authors: Frova A. , Migliorato P.
Published: January 2004

Electromodulation of the interference spectrum of thin anodized Ta2O5 films is analyzed by means of multiple interference theory. The analysis confirms that the dominant effect is an electro-optic modulation of the refractive index of the film, rather than electrostriction. It is also found that the electro-optical behavior is similar to that shown by oxygen-octahedra ferroelectriclike single crystals.
EFFECTS OF SILICON NITRIDE GROWTH TEMPERATURE ON CHARGE STORAGE IN THE MNOS STRUCTURE
Authors: Ross E. C. , Duffy M. T. , Goodman A. M.
Published: January 2004

Experimental results of the effects on charge storage in the MNOS structure by varying the growth temperature of the silicon nitride are presented. The range of growth temperature examined is 650–1100°C. The initial charge stored is positive at the lower temperatures, negative at the higher temperatures. The maximum positive charge that can be stored varies continuously with growth temperature. The ability to retain the stored charge when the charging voltage is removed decreases monotonically with increasing growth temperature.
TUNNEL-DIODE PHOTORESPONSE
Authors: Adams Richard F. , Rosenberg Robert L.
Published: January 2004

The photoresponse of tunnel diodes has been found to be fast enough under suitable conditions to follow subnanosecond light pulses from a mode-locked He–Ne laser. The nonlinearity of the diode electrical characteristic has yielded threshold detection of optical pulses having a peak power of a few milliwatts. Tunnel diodes of varied materials and construction show a similar photoresponse so long as optical frequency exceeds the (indirect) band gap.
p-TYPE CADMIUM SULFIDE CRYSTALLINE FILMS
Authors: Lichtensteiger M. , Lagnado I. , Gatos H. C.
Published: January 2004

p-type conduction in (000l)-oriented CdS films sputtered in the presence of phosphine was observed. dc Hall measurements are presented and p-n junction characteristics are shown.
OBSERVATION OF RADIATION FROM NONLINEAR POLARIZATION SIDEBAND IN ARGON LASERS
Authors: Statz H. , deMars G. A. , Tang C. L.
Published: January 2004

An argon laser oscillating at 4880 and 5145 Å, when the cavity lengths for the two transitions have been made unequal, shows anomalous beat notes in the 4880 Å line which correspond to mode spacing characteristic of the 5145 Å line, and similarly, the 5145 Å line beat spectrum contains frequencies belonging to the 4880 Å cavity. These observations are quantitatively explained by radiation from nonlinear polarization sidebands. The interaction between the lines occurs via their common lower laser state. Nonlinear polarization sidebands have been postulated in the past to be responsible for mode-locking phenomena and the generation of ultrashort pulses, but their direct observation in conventional lasers is, in general, difficult since the polarization sidebands coincide with cavity modes.
THEORETICAL CALCULATION OF PHOTOCONDUCTIVITY INDUCED BY A MULTIPLE-PHOTON ABSORPTION PROCESS IN SEMICONDUCTORS
Authors: Yee Jick H.
Published: January 2004

Based on a volume and a surface recombination process, a general theoretical calculation of the photoconductivity induced by a multiple-photon absorption process is presented. As an example, the calculation is applied to the two-photon absorption process.
GaAs1−xPx AS A NEW HIGH QUANTUM YIELD PHOTOEMISSIVE MATERIAL FOR THE VISIBLE SPECTRUM
Authors: Simon R. E. , Sommer A. H. , Tietjen J. J. , Williams B. F.
Published: January 2004

A new photocathode having high quantum yield for visible and ultraviolet radiation is reported. The cathode consists of a cesium-activated strongly p-type doped GaAs1−xPx alloy.
HOLOGRAPHY OF RANDOMLY MOVING OBJECTS
Authors: Mottier François M.
Published: January 2004

It is shown that holograms of randomly moving objects can be taken if the reference wave is suitably phase-modulated. By means of a mirror attached to the object, the modulation may be achieved automatically.
PULSE PAIR RESOLUTION IN A PULSE SATURATED CHANNELTRON ELECTRON MULTIPLIER
Authors: Wolber W. G. , Klettke B. D. , Miller J. S. , Schmidt K. C.
Published: January 2004

The pulse pair resolution of a Channeltron electron multiplier has been examined for two cases; the quiescent case and the case where it is operated at an average count rate of 1.1 megapulses/sec. In both cases, the pulse pair resolution has been found to be comparable to the pulse width, which is about 2 × 10−8 sec at the base.
NEW FLUORIDE COMPOUNDS FOR EFFICIENT INFRARED-TO-VISIBLE CONVERSION
Authors: Guggenheim H. J. , Johnson L. F.
Published: January 2004

Efficient infrared-to-visible conversion by Yb3+–Er3+ and Yb3+–Ho3+ ions in BaLuF5 and BaYF5 is reported. When pumped by radiation from a Si–GaAs diode, the power conversion efficiency for green emission from BaYF5:Yb3+, Er3+ is equal to that for green emitting GaP diodes.
EFFICIENT INFRARED-TO-VISIBLE CONVERSION BY RARE-EARTH OXYCHLORIDES
Authors: Van Uitert L. G. , Singh S. , Levinstein H. J. , Johnson L. F. , Grodkiewicz W. H. , Geusic J. E.
Published: January 2004

When pumped by radiation from a Si–GaAs diode, the luminous efficiency of Y3OCl7:Yb3+, Er3+ is comparable to that of visible emitting GaP diodes. By varying the Yb3+ concentration, phosphors have been made which produce a red or yellow visual response.
BULK AND THIN FILM SWITCHING AND MEMORY EFFECTS IN SEMICONDUCTING CHALCOGENIDE GLASSES
Authors: Stocker H. J.
Published: January 2004

Switching phenomena take place in thick bulk samples of semiconducting glass, once a path of devitrified material is established. Potential probe and infrared microradiometer measurements reveal that the switching action takes place in a small region somewhere along this path. Application of voltage pulses can move this region to a different position. Evidence of partial devitrification and melting is also found in thin film switches made from many different glass compositions. Memory switching has also been observed in all bulk and thin film experiments to date. Since the characteristics of bulk and thin film switching are remarkably similar, doubt is cast upon the interpretation of switching phenomena as due to electronic properties of amorphous semiconductors.
IMAGE CONTRAST IN A TRANSMISSION SCANNING ELECTRON MICROSCOPE
Authors: Cowley J. M.
Published: January 2004

The appearance of phase-contrast, Fresnel fringes and various forms of diffraction contrast in images produced by transmission scanning electron microscopes can be understood simply by invoking the principle of reciprocity to equate the imaging conditions to those relevant to a conventional electron microscope.
MULTIMODE OSCILLATION AND AMPLIFICATION IN PINCHED ELECTRON-HOLE PLASMAS
Authors: Chen Wen S. , Ancker-Johnson Betsy
Published: January 2004

An azimuthally symmetric perturbation in the density distribution of a pinched electron-hole plasma produces spontaneous pinch oscillations which grow in time and space. Applied waves with this symmetry are amplified as they propagate down the pinch while the plasma is biased just below the current threshold for spontaneous oscillation. Magnetic fields applied parallel to the current cause helical perturbations to grow. Waves with helical symmetry grow markedly only when the plasma is just below its pinch threshold. Phase-discriminating wave amplification is achieved when the plasma is properly biased.
AN ANALYTIC APPROACH TO THE ELECTRON DRIFT VELOCITY IN GALLIUM ARSENIDE FOR DIFFERENT TEMPERATURES
Authors: Lundgren L. , Olsson K.
Published: January 2004

The intervalley scattering of electrons in gallium arsenide at high electric fields has been considered by approximating the energy distribution of the electrons by a Davydov distribution. From this distribution the velocity-field curve for the electrons has been determined and compared to experiments. Using the results, the temperature dependence of the threshold field and the efficiency of LSA-diodes has been calculated.
Q SWITCHING OF THE CARBON MONOXIDE LASER
Authors: Osgood R. M. , Nichols E. R. , Eppers W. C. , Petty R. D.
Published: January 2004

Peak powers of from 1 to 7.7 kW have been obtained from a Q-switched CO-air-He laser with 120 cm of active medium. The energy of the Q-switched pulse was distributed in approximately 60 lines with wavelengths from 5.05 to 6.20 μ. Use of a grating as a cavity wavelength selector enabled single line operation, with peak powers up to 280 W in some transitions. A measurement of the laser recovery time and the CO vibrational temperature for the V = 7 → V = 6 band is reported.
FAR-INFRARED ABSORPTION IN HIGH RESISTIVITY GaAs
Authors: Stolen R. H.
Published: January 2004

The absorption of high resistivity GaAs has been measured in the spectral region 15 to 190 cm−1 at room temperature and at 82°K. The observed temperature and frequency dependence indicate an absorption dominated by 2-phonon difference processes.
PREPARATION OF A LIGHT FOCUSING GLASS ROD BY ION-EXCHANGE TECHNIQUES
Authors: Pearson A. David , French William G. , Rawson Eric G.
Published: January 2004

A glass rod with a radially graduated refractive index was produced by replacing the lithium ions contained in the glass composition with sodium ions from a fused salt bath. Glass rods with such refractive index gradients are potentially useful as low resolution imaging devices.
EFFICIENT, TUNABLE OPTICAL EMISSION FROM LiNbO3 WITHOUT A RESONATOR
Authors: Yarborough J. M. , Sussman S. S. , Purhoff H. E. , Pantell R. H. , Johnson B. C.
Published: January 2004

We report the first observation of tunable stimulated optical emission from a nonlinear crystal without the use of an external resonator, and with greater than 50% conversion of the pump beam to the tunable frequency. Opposite faces of a LiNbO3 crystal were polished flat and parallel to provide for multiple reflections of the signal radiation (Stokes) inside the crystal. The A1 symmetry 248-cm−1 polariton mode was excited with a Q-switched ruby laser, and the signal frequency was tuned by varying the angle of incidence of the laser beam relative to the normal to the crystal surface. Operation was at room temperature; no crystal damage was observed over most of the tuning range; and laser depletion occurred within the first few nanoseconds of the Q-switched pulse. The difference between the Stokes frequency and laser frequency was varied from 42 to 200 cm−1, and the corresponding idler wavelength was varied from 238 to 50 μ.
OPTICAL PULSES FROM cw GaAs INJECTION LASERS
Authors: Paoli Thomas L. , Ripper José E.
Published: January 2004

Intensity pulsations of continuously operating GaAs injection lasers have been directly observed for the first time, with fast sampling techniques. The width of the self-induced pulses has been measured to be approximately 390 psec at a repetition rate of 620 MHz. In addition, this pulsewidth has been reduced to less than 200 psec by locking the pulsations with an external modulation of the injection current.
MAGNETO-OPTICAL STUDY OF MAGNETIC FIELD DEPENDENCE OF SPIN-LATTICE RELAXATION TIMES IN CaF2: Eu2+
Authors: Giltner Beverly S. , Lysiak Richard J.
Published: January 2004

The maximum rate at which paramagnetic ions in a crystal lattice can respond to a modulating magnetic field superimposed on a static magnetic field is determined by the characteristic relaxation time of the ions. At low temperatures and nonzero static magnetic field the spin-lattice relaxation time (τ) is the dominant characteristic relaxation time. The influence of τ at low temperatures on the phase and amplitude of the ac Faraday rotation is quantitatively described. Experimental results for Eu2+-doped CaF2 are reported which verify the theoretical concepts and yield τ values at 9°K which vary linearly with the applied static magnetic field.
LEAD MOLYBDATE: A MELT-GROWN CRYSTAL WITH A HIGH FIGURE OF MERIT FOR ACOUSTO-OPTIC DEVICE APPLICATIONS
Authors: Pinnow D. A. , Van Uitert L. G. , Warner A. W. , Bonner W. A.
Published: January 2004

Crystalline lead molybdate PbMoO4 has been found to be well suited for acousto-optical device applications. This material has desirable properties similar to the previously reported α-iodic acid α-HIO3. However, PbMoO4, unlike α-HIO3, is insoluble in water and can therefore be readily fabricated into devices and its optical surfaces do not require protection from the atmosphere. The elastic, photoelastic, optical, and thermal properties of PbMoO4 have been measured. These data have been used in the design of several acousto-optic devices. An example consisting of a two stage (horizontal and vertical) acoustically driven light deflector is described. Each stage of this deflector has an 80-MHz bandwidth and can deflect over 50% of an incident laser beam (5145 Å) with less than 1 W of electrical drive power.
cw OPERATION OF HIGH-PRESSURE FLOWING CO2 LASERS
Authors: Deutsch Thomas F. , Horrigan Frank A. , Rudko Robert I.
Published: January 2004

The performance of N2–CO2–He lasers operating at pressures in the 10–120-Torr range and with nitrogen flow rates of 20–90 standard liters per minute is discussed. A 10-cm-long, 13.5-mm-i.d. discharge tube produced 140-W output power. These lasers operate as in-line mixing lasers, producing about one photon per excited nitrogen molecule. Cooling is provided by rapid removal of hot gas from the discharge region.
300°K ANNEALING OF ELECTRON DAMAGE IN LITHIUM-DOPED SILICON
Authors: Stannard J. E.
Published: January 2004

Electron irradiation of lithium-doped silicon at 77°K causes an increase in acceptor concentration as measured by Hall effect. Subsequent annealing at 300°K causes this acceptor concentration to decrease along with an associated decrease in the concentrations of both isolated lithium and lithium paired with oxygen. The decrease in lithium content substantially exceeds the decrease in acceptor concentration.
1.75-GHz ACOUSTIC-SURFACE-WAVE TRANSDUCER FABRICATED BY AN ELECTRON BEAM
Authors: Broers A. N. , Lean E. G. , Hatzakis M.
Published: January 2004

Surface-acoustic-wave interdigital transducers operating at 1.75 GHz have been fabricated on y-cut z-oriented LiNbO3 and y-cut x-oriented quartz substrates by electron-beam techniques. The transducers consist of 25 pairs of interleaved aluminum ``fingers'' 0.3 μ wide and 0.7 μ apart. Used as a surface acoustic wave delay line, the insertion loss has been measured to be as low as 25 dB with a bandwidth of 70 MHz for 2.2-μsec delay. The parameters of the equivalent circuit of the transducer have been measured and agree with the theoretical calculation.
LASER RECOMBINATION TRANSITION IN p-TYPE GaAs
Authors: Rossi J. A. , Holonyak N. , Dapkus P. D. , McNeely J. B. , Williams F. V.
Published: January 2004

Data are presented (77°K) showing that laser transitions to either the valence band edge or to the acceptor, or both, are possible in a specific impurity concentration range (2 × 1017−1018/cm3) in GaAs:Zn and GaAs:Cd. These data are observed on a low-loss crystal structure that is pumped uniformly.
OSCILLATION AND DOUBLING OF THE 0.946-μ LINE IN Nd3+:YAG
Authors: Wallace R. W. , Harris S. E.
Published: January 2004

The paper reports oscillation and doubling of the 0.946-μ line in Nd3+:YAG. Peak, Q-switched output powers of approximately 2 kW at 0.473 μ were obtained. The results of a calculation for optimum nonlinear coupling to an internal Q-switched laser are given.
KINETICS AND EFFICIENCY OF INFRARED-TO-VISIBLE CONVERSION IN LaF3:Yb,Er
Authors: Kingsley J. D. , Fenner G. E. , Galginaitis S. V.
Published: January 2004

The results of an analysis of the energy transfer and two-step excitation in LaF3:Yb,Er are presented. The physical model assumes that the Yb3+ and Er3+ ions are tightly coupled and transfer occurs both ways. The simple model used is able to explain the experimentally observed time dependence and radiant efficiency provided one assumes the following decay times: Yb3+(5F5/2), 2 msec; Er3+(4F7/2), ∼1 μsec; Er3+(4S3/2), 0.125 msec.
COOLING LIMITS FOR SOLENOID STABILIZATION IN THE VICINITY OF THE He4 λ-POINT
Authors: Frederking T. H. K. , Purdy Vance
Published: January 2004

The superfluid He II transition to the normal state and the critical dissipation rates for near-isothermal solenoid operation have been measured near the λ point. In contrast to the superfluid quenching limit, the solenoid cooling stability limit was found to be finite at the λ point.
HARMONIC GENERATION AND SUBMILLIMETER WAVE MIXING WITH THE JOSEPHSON EFFECT
Authors: McDonald D. G. , Kose V. E. , Evenson K. M. , Wells J. S. , Cupp J. D.
Published: January 2004

By observing constant-voltage steps from Josephson junctions at voltages as high as 17 mV we deduce that junctions can generate harmonics up to frequencies as high as 8200 GHz. In consonance with this, submillimeter wave laser detection, harmonic generation, and mixing are demonstrated. These results suggest a model for the upper frequency limit of the Josephson effect.
POSSIBILITY OF ULTRAHIGH CRITICAL FIELDS IN GRANULAR HARD SUPERCONDUCTORS
Authors: Watson J. H. P.
Published: January 2004

This paper suggests that refractory superconductors in the form of grains connected by electron tunneling may possess upper critical fields in the megagauss range.
CONTROL OF ELECTRON EMISSION BY ELASTIC SURFACE WAVES
Authors: Blackledge V. O. , Kaufman I.
Published: January 2004

Control of electron emission from a photoemissive surface on a piezoelectric substrate by the electric fields of an elastic wave has been demonstrated.
PHOTOLUMINESCENCE OF OXYGEN IN ZnTe INTRODUCED BY ION IMPLANTATION
Authors: Merz J. L. , Feldman L. C.
Published: January 2004

Photoluminescence has been observed from oxygen (O16) ions implanted into ZnTe. Doses of 5 × 1013 oxygen ions/cm2 were implanted at room temperature with energies between 50 and 250 keV. After annealing at 300–400°C in zinc vapor, the characteristic photoluminescence spectrum from the oxygen isoelectronic trap was observed. Care was taken to ensure that the spectrum was a direct result of the implanted oxygen by studying unimplanted and neon-implanted samples. The anticipated isotope shift was observed in the spectrum for samples implanted with O18.
ON THE NATURE OF Si (111) SURFACES
Authors: Grant J. T. , Haas T. W.
Published: January 2004

The Auger spectrum of the cleaved (111) Si surface shows the same transitions as that of an annealed surface having a Si(111)7 structure. This result indicates that the previously observed transitions in the Auger spectrum of Si(111)7 surfaces are all due to Si and that there is no evidence that the Si(111)7 structure is impurity stabilized.
LOW FIELD INJECTION IN n-InSb
Authors: Ancker-Johnson Betsy , Dick C. L.
Published: January 2004

Contrary to a widely accepted notion, considerable plasma injection occurs in n-InSb at 77°K subjected to low electric field strengths (e.g., 20 V/cm) and fitted with ``Ohmic'' contacts (indium solder).
ELECTROSTRICTION-INDUCED MODULATION OF THE REFLECTANCE OF ANODIC OXIDE FILMS
Authors: Holden B. J. , Ullman F. G.
Published: January 2004

The electroreflectance of anodic oxide films, at wavelengths longer than the absorption edge, has been proposed to result from an electro-optic modulation of the refractive index. It is shown here that it is also possible to attribute the observed behavior to a modulation of the oxide film thickness by the electrostatic attraction of the electrodes.
STABLE, CHIRPED, ULTRASHORT PULSES IN LASERS USING THE OPTICAL KERR EFFECT
Authors: Comly J. C. , Yariv A. , Garmire E. M.
Published: January 2004

A self-consistent analysis of pulse propagation inside a laser cavity containing, in addition to an amplifying medium, some material displaying the optical Kerr effect, yields ultrashort pulses. These pulses become stable in the limit of high line-center excess gain with the stabilization provided by an interplay between strong chirping in the Kerr medium and bandlimiting in the laser medium.
ELECTRICAL CONDUCTION IN SINGLE-CRYSTAL ALUMINUM THIN FILMS
Authors: Jayadevaiah T. S. , Kirby Robert E.
Published: January 2004

Electrical conduction in thin (400−1500 Å) single-crystal aluminum films vacuum evaporated on NaCl substrates is explained by a simple model and verified by experimental results. The resistivity of the inter-island boundaries is accounted for by considering the film structure as a metal—insulator matrix and calculating its equivalent resistivity. An unambiguous comparison can then be made with the Fuchs—Sondheimer theory of size-affected conduction in thin metal films only after subtracting off the resistivity contribution due to interisland boundaries.
MAGNETOSTRICTIVE GENERATION OF SURFACE ELASTIC WAVES
Authors: Voltmer F. W. , White R. M. , Turner C. W.
Published: January 2004

Surface elastic waves have been generated at 60 MHz by magnetostrictive coupling in yttrium iron garnet (YIG). The transducers were evaporated aluminum meander lines. For a YIG plate with the (110) axis normal to the free surface and propagation along the (001) axis, maximum coupling occurred for the static field parallel to the direction of propagation. The effect of the internal magnetic field gradient on the transducer efficiency and the signal delay is discussed.
STABLE, LONG LIFE cw EXCITATION OF HELIUM-CADMIUM LASERS BY dc CATAPHORESIS
Authors: Goldsborough John P.
Published: January 2004

A technique for maintaining a spatially uniform and optimum concentration of cadmium vapor in a helium—cadmium laser discharge tube is described. Cadmium vapor, continuously fed in at the anode end of the discharge tube, flows by cataphoresis to the cathode end where it is condensed on a cold surface.
LOW-TEMPERATURE HIGH-FREQUENCY CAPACITANCE MEASUREMENTS OF DEEP-AND SHALLOW-LEVEL IMPURITY CENTER CONCENTRATIONS
Authors: Sah C. T. , Rosier L. L. , Forbes L.
Published: January 2004

A simple method is proposed and demonstrated for the determination of a minute amount of deep-level impurities in the transition region of p-n junctions from the high-frequency capacitance change when the junction temperature is lowered from room temperature to 77°K and the junction bias is switched to zero and back to the large reverse bias to set the charge trapped at these centers to the equilibrium value. Sensitivity of 1011 atoms/cm3 and 105 total atoms in the depletion layer is demonstrated in junction gettered by phosphorus glass. Examples are also given for Ni- and Audoped silicon diodes and transistors.
COUPLING OF LIGHT EMISSION AND NEGATIVE RESISTANCE IN A GaAs DIODE
Authors: Zuleeg R. , Ranon U.
Published: January 2004

Electrical and optical evaluations of a lateral GaAs P+N-junction are reported. The current-voltage characteristics of these devices produce a double current-controlled negative-resistance behavior and a region with bulk negative-resistance instability which is coupled with simultaneous emission of light at a wavelength of 8800 Å at 300°K. Near-sinusoidal oscillations from 200 KHz to 10 MHz were obtained and the frequency of oscillation is a function of applied voltage, i.e., current, and temperature. The effect of an applied magnetic field on the current-voltage characteristics and oscillating frequencies was also investigated.
AVALANCHE INJECTION CURRENTS AND CHARGING PHENOMENA IN THERMAL SiO2
Authors: Nicollian E. H. , Goetzberger A. , Berglund C. N.
Published: January 2004

Injection of carriers into thermally grown SiO2 from an avalanche plasma in silicon is a new way of achieving high current densities in SiO2. Electron injection from p-type silicon and hole injection from n-type silicon by hot carrier emission have been observed. Average electron current densities as high as 10−2 A/cm2 have been observed to flow through 1000 Å of SiO2. The oxide becomes negatively charged as a result of electron injection and positively charged as a result of hole injection. These charging effects appear to be related to the presence of water in the oxide.
COLLISIONAL RELAXATION OF CO2 ROTATIONAL LEVELS BY N2 AND He
Authors: Abrams R. L. , Cheo P. K.
Published: January 2004

The effects of N2 and He on the rotational relaxation rate of the CO2 00°1 upper laser level have been measured. These gases were found to be slightly less effective than CO2 in thermalizing the rotational energy levels.
FREQUENCY-LOCKING OF ORGANIC DYE LASERS TO ATOMIC RESONANCE LINES
Authors: Sorokin P. P. , Lankard J. R. , Moruzzi V. L. , Lurio A.
Published: January 2004

Locking of the output of a flashlamp-pumped Rhodamine 6G dye laser to the D lines of sodium vapor was achieved by means of the large Faraday rotation that occurs in the vicinity of the resonance lines. The laser beam was observed to consist spectrally of two sharp components symmetrically disposed on either side of the D1 and D2 lines. The laser doublet splitting varies with magnetic field.
TWO-PHOTON IONIZATION PROCESS IN OPTICAL BREAKDOWN OF CESIUM VAPOR
Authors: Okuda Takayoshi , Kishi Kumeyo , Sawada Katsutoshi
Published: January 2004

Optical breakdown of cesium vapor by Q-switched laser light is studied. The threshold laser power density for the breakdown is observed over fairly wide range of the cesium atoms density. A pair of probes are inserted in the vicinity of the focal point for the purpose of detecting the occurrence of breakdown. The magnitude of the threshold laser power density and its dependence on the atom density measured by us are different from those reported by Rizzo and Klewe. The present result confirms the validity of the two-photon ionization mechanism suggested by Bebb and Hall.
PARAMETRIC AMPLIFICATION IN AN rf SUSTAINED PLASMA CAPACITOR
Authors: Asmussen Jes , Lee Quong H.
Published: January 2004

The experimental results of a radiation-induced instability in a completely rf sustained plasma capacitor discharge are discussed. Nonlinear coupling between electron plasma modes and ion-acoustic modes has been observed resulting in a four-frequency parametric interaction. By reducing the microwave pump power below the power threshold required for the instability, the rf pumped plasma capacitor is able to amplify a separately applied cw input signal when this signal is in the vicinity of one of the parametric resonances. Experimental results are presented which show the effect of the capacitor size and input pump power on the parametric interaction.
PHASE-MATCHED NONLINEAR INTERACTION BETWEEN CIRCULARLY POLARIZED WAVES
Authors: Patel C. K. N. , Van Tran N.
Published: January 2004

This paper reports the first observation of phase-matched nonlinear interaction between three circularly polarized waves.
AN ULTRAFAST LIGHT GATE
Authors: Duguay M. A. , Hansen J. W.
Published: January 2004

A simple technique is described for gating light on and off on the picosecond time scale. The gate is built in much the same fashion as traditional Kerr cells, the difference lying in the use of powerful optical pulses rather than electrical pulses to induce a birefringence in various liquids. The direct observation of the exponential decay (τ = 32 ± 6 psec) of the birefringence induced in nitrobenzene shows that orientational effects are largely responsible for the refractive index changes induced by light in this liquid.
EFFECT OF HOST DISPERSION ON MODE-LOCKED LASERS
Authors: Smith Archibald W.
Published: January 2004

Analytic expressions for the frequency sweep (chirp) and pulse width are given for externally-locked lasers with host dispersion. The expressions have been obtained using a self-consistent circulating pulse method. For both phase and amplitude modulation, the pulse is broadened by the host dispersion. However, only phase modulation can give the large frequency sweeps which allow the pulse to be compressed outside the laser. This result helps one to understand some conflicting observations on chirping in the Nd:glass laser.
TRANSVERSE WAVES IN DETONATING LIQUIDS
Authors: Howe Philip M.
Published: January 2004

Evidence for the existence of transverse waves in detonating liquid explosives is presented. The technique utilized is analogous to the smoked-foil technique used in gaseous detonation studies.
ON THE MECHANISM OF IONIC CONDUCTION AT HIGH FIELDS
Authors: Digham M. J. , Taylor D. F.
Published: January 2004

The dielectric polarization theory for ionic conduction at high fields is shown to predict a decrease in the measured ac film capacitance for an increase in the dc ion current, contrary to the assertion of Dell'Oca and Young.
THREE-DIMENSIONALLY TRAPPED RADIATION IN A NONLINEAR DIELECTRIC
Authors: Woo James W. F.
Published: January 2004

A totally localized solution of the wave equation in a nonlinear dielectric is discussed. The spatial region in which the field is concentrated has the shape of a torus. The solution is never completely stable, but under suitable conditions the lifetime of the trapped radiation can be extremely long.