bluuebunny/crossref_metadata_2025 huggingface dataset:
A TUNABLE, ACOUSTICAL PHONON DETECTOR USING Tm2+ IN CaF2
Authors: Sabisky E. S. , Anderson C. H.
Published: January 2004

The sensitivity and versatility of a phonon detector based on the optical detection of the spin population difference of an impurity ion through the spin-phonon interaction is demonstrated. Phonons generated at 1.4°K by a variety of transducers using at most several milliwatts of rf power at 9.5 GHz were detected. Phonons generated at the 2nd and 3rd harmonics were also detected.
MAGNETOACOUSTIC AMPLIFICATION IN InSb
Authors: Hammar C. , Weissglas P.
Published: January 2004

A quantum theory of magnetoacoustic amplification in semiconductors is given. Calculations for InSb show that the quantum theory can explain both branches of the acoustoelectric current oscillations observed by Kikuchi1 and Kino.2 For high electron drift velocities the gain shows a resonant behavior when the Doppler-shifted acoustic frequency is equal to a multiple of the Larmor frequency.
TIME RESOLVED MEASUREMENTS OF ELECTRON NUMBER DENSITY AND ELECTRON TEMPERATURE USING LASER INTERFEROMETRY AT 337-μm WAVELENGTH
Authors: Parkinson G. J. , Dangor A. E. , Chamberlain J.
Published: January 2004

An experiment is described where a cw HCN laser working primarily at 337-μm wavelength was used as the source of a Mach-Zehnder interferometer for the study of plasma decay in the electron number density region 5 · 1015 > ne > 5 · 1013 cm−3. It was found that an estimate of the electron temperature in the range 103−104°K could also be made from the amplitude of the interferometer fringes.
MAGNETIC FIELD DEPENDENCE OF ACOUSTOELECTRIC CURRENT OSCILLATION IN n-InSb
Authors: Abe Y. , Mikoshiba N.
Published: January 2004

A theory is given for two branches, I and II, of acoustoelectric current oscillation under a transverse magnetic field in n-InSb. The peculiar behavior of branch I at high electric fields can be explained by the ``Doppler-shifted'' amplification and the drastic change of magnetic field dependence of amplifcation of phonons, both of which are due to the large drift velocity of electrons.
RANGE AND DISTRIBUTION OF IMPLANTED BORON IN SILICON
Authors: Davies D. Eirug
Published: January 2004

The range and distribution of 200- and 400-ke V boron implanted into silicon in a nonchanneling direction has been investigated by a differential capacitance method. While the range is found to correspond to that predicted from Lindhard's theory of amorphous stopping, the mean deviation does not. From the symmetry of the observed distribution, it is concluded that channeling is not responsible for the discrepancy.
BRAGG REFLECTION OF LASER LIGHT FROM A PHASE GRATING IN A Q-SWITCHING LIQUID
Authors: Harrison R. G. , Key P. , Little V. I. , Magyar G. , Katzenstein J.
Published: January 2004

It is postulated that in a saturable dye absorber used for giant pulse laser switching a phase grating is formed. To prove this experimentally a frequency doubled part of the laser beam was reflected from this ``Lippman plate'' at the Bragg angle.
EXCESS CURRENT GENERATION DUE TO REVERSE BIAS P-N JUNCTION STRESS
Authors: Collins D. R.
Published: January 2004

A previously unreported method of generating excess p-n junction current is shown to degrade the current gain of transistors. Experimental evidence indicates the excess current is a surface effect which is not associated with ion drift. Avalanche breakdown is shown to be neither a necessary nor sufficient cause for degradation.
ENHANCEMENT OF SENSITIVITY IN ESCA SPECTROMETERS
Authors: Helmer J. C. , Weichert N. H.
Published: January 2004

In x-ray photoelectron spectroscopy the electron current may be increased by retarding the source electrons if, at the same time, the design of the spectrometer is matched to the retarded source.
THERMAL SELF-FOCUSING OF LASER BEAMS IN LEAD GLASSES
Authors: Dabby F. W. , Whinnery J. R.
Published: January 2004

Strong thermal self-focusing of an argon laser beam has been observed when the beam passes through lead glass. Focal lengths of less than 20 cm were obtained. The beams showed the effects of spherical aberration and at certain power levels beam trapping occurred. A simple theory is proposed to explain the observed trapping. Computer solutions have been obtained which reasonably agree with experimental determination of focal planes and spot radius.
DETECTION OF FAST INFRARED LASER PULSES WITH THIN FILM THERMOCOUPLES
Authors: Day G. W. , Gaddy O. L. , Iversen R. J.
Published: January 2004

A thin-film thermocouple detector, suitable for use with molecular lasers operating in the middle and far infrared has been developed. Measured response times are approximately 10−7 sec. The noise equivalent power is of the order of 10−7 W/Hz.
P-N JUNCTIONS AS ARTIFICIAL DIFFUSION BARRIERS FOR NATIVE DEFECTS
Authors: Aven M. , Hall R. B. , Garwacki W.
Published: January 2004

A diffusion anomaly of a native acceptor defect in ZnSexTe1−x p-n junctions is described. The diffusivities of this defect in n- and p-type crystals at 575°C have been determined. The anomaly can be utilized in a triple-diffusion technique of preparing p-n junction diodes with improved electrical properties.
ZEEMAN SPLITTING USED TO INCREASE ENERGY FROM A Q-SWITCHED IODINE LASER
Authors: Gregg David W. , Kidder Ray E. , Dobler Champe V.
Published: January 2004

Magnetic broadening of the iodine lasing line was found to increase the energy storage capability of the laser and thus increase the energy obtainable in a Q-switched pulse from a few millijoules to a few tenths of a joule.
GAIN INTERACTION AND DYNAMICAL BEHAVIOUR OF A MULTIMODE He–Ne LASER
Authors: Bambini A. , Burlamacchi P.
Published: January 2004

The buildup of the modes of a He–Ne laser in the presence of other strongly oscillating modes was analyzed. Owing to the gain interaction the buildup time was found to be about one order of magnitude greater than for freely growing modes and to be greatly dependent on the position of the modes under the Doppler curve. The active bandwidth for the low-frequency noise due to the presence of combination tones near the modes was derived from these measurements.
LOCKING A LASER FREQUENCY TO THE TIME STANDARD
Authors: Bay Z. , Luther G. G.
Published: January 2004

On the basis of high-frequency modulation experiments and well-known locking techniques, a scheme is described for stabilizing a visible laser frequency and simultaneously determining that frequency in terms of the time standard. The importance of this method for a refined determination of the velocity of light and the possibility of establishment of reference lines for spectroscopy and for length measurements, throughout the spectrum wherever laser lines are available, is discussed.
MICROWAVE ECHOES IN GASEOUS NH3
Authors: Jenkins J. L. , Wagner Peter E.
Published: January 2004

Echoes have been observed at microwave frequencies, resulting from electromagnetic field excitation of electric dipole transitions between inversion states in gaseous NH3. This paper reports preliminary observations made on a microwave echo spectrometer to be used to investigate homogeneous relaxation processes.
TEMPERATURE DEPENDENCE OF CONCENTRATION FLUCTUATIONS IN A BINARY LIQUID MIXTURE USING A PHOTON CORRELATION METHOD
Authors: Pusey P. N. , Goldberg W. I.
Published: January 2004

A photon correlation method has been demonstrated to be effective in measuring the width of narrow spectral lines of relatively low intensity. The method has been used to measure the temperature dependence of the diffusion constant in the phenol-water system. It was found that D ∝ (T − Tc)0.76±0.02 for 1° ≲ T − Tc ≲ 15°C.
ELASTIC SURFACE WAVES ON LAYERED ANISOTROPIC CRYSTALS
Authors: Loftus D. S.
Published: January 2004

A general numerical method has been developed for the determination of the modes of propagation, phase velocities, displacements, magnitude and direction of energy flow of elastic surface waves when any layer of anisotropic material is in contact with any underlying semi-infinite anisotropic crystal. Such characteristics have been calculated for a variety of anisotropic layer and crystal combinations. Typical results are presented.
FORWARD CURRENT-VOLTAGE CHARACTERISTICS AND DIFFERENTIAL RESISTANCE PEAK OF A SCHOTTKY BARRIER DIODE ON HEAVILY DOPED SILICON
Authors: Saxena A. N.
Published: January 2004

An analysis of the forward current-voltage data for a temperature range of 77.2° to 423°K on a Cr–Si (ND = 7 × 1018 cm−3) Schottky barrier diode is given. The I-V behavior of such a diode, which obviously does not follow the simple Schottky theory, is not explained by the more recent calculations of Padovani and Stratton, and of Crowell and Rideout in which field emission is taken into account. It is observed that the peak in differential resistance and its variation with voltage on such a diode is in reasonable agreement with the theories of Stratton and Padovani, and of Crowell and Rideout.
THE EFFECT OF TRAPPING STATES ON TUNNELING IN METAL-SEMICONDUCTOR JUNCTIONS
Authors: Parker G. H. , Mead C. A.
Published: January 2004

The tunneling behavior of Schottky barriers has been investigated by several authors. The I-V characteristics exhibit an exponential form in the forward direction which can be used to determine the energy vs complex momentum dispersion relation for charge carriers in the forbidden gap. In this paper we show that under proper conditions the presence of traps can increase the tunneling probability and result in a reduction in the slope of the log I vs V characteristic by a factor of 2.
INFRARED UP CONVERSION IN LITHIUM-NIOBATE WITH LARGE BANDWIDTH AND SOLID ACCEPTANCE ANGLE
Authors: Midwinter J. E.
Published: January 2004

We report the experimental study of the up-conversion of infrared radiation in the range 2.0 to 4.0 μ in lithium niobate with a Nd-YAG laser pump, under conditions of phase-matching which are simultaneously noncritical in both infrared input angle and wavelength. An increase in the phase-matched bandwidth of nearly two orders of magnitude was observed over previous work.
CURRENT OSCILLATIONS IN PHOTOEXCITED GALLIUM-ARSENIDE
Authors: Viehmann Walter
Published: January 2004

Optically excited current oscillations in oxygen-compensated and chromium-compensated GaAs devices are described. Their relation to deep acceptor levels inferred from photoconductivity excitatation spectra is pointed out.
DETERMINATION OF INTERNAL ELECTRIC FIELDS IN SILICON DIOXIDE LAYERS BY OPTICAL PROBING
Authors: Protschka H. A. , Frankovsky F.
Published: January 2004

Existing nominal electric fields in unirradiated and electron-bombarded silicon dioxide layers of SOS-sandwich structures were determined by means of optical probing. The method of investigation is based on the quadratic electro-optical Kerr effect and employs a suitable optical arrangement in connection with a 0.6328-μ helium-neon laser.
MULTIPHOTON EXCITATION OF FLUORESCENCE IN STANDING LIGHT WAVES AND MEASUREMENT OF PICOSECOND PULSES
Authors: Drexhage K. H.
Published: January 2004

The spatial variation of the fluorescence intensity after multiphoton absorption in dye solutions is explained in terms of standing light waves. The mirror reflectivity affects the contrast ratios. Furthermore, the influence of the mirror on the process of fluorescence emission is considered.
RAMAN-NATH DIFFRACTION IN ORGANIC CRYSTALS
Authors: Wolkerstorjer D. C.
Published: January 2004

The diffraction of light by ultrasound has been measured at 53 MHz in anthracene, naphthalene, and sugar. Anthracene is found to be more efficient than water in this respect while naphthalene and sugar are more efficient than lithium niobate. Acoustic attenuation has also been measured in anthracene over a frequency range of 10 to 150 MHz.
METHOD TO LOCK AN OPTICAL PARAMETRIC OSCILLATOR TO AN ATOMIC TRANSITION
Authors: Harris S. E.
Published: January 2004

A method to lock the output frequency of an optical parametric oscillator to an absorbing atomic transition is proposed. The effective linewidth of the oscillator becomes approximately that of the absorbing transition.
A THERMALLY PUMPED CO2 LASER
Authors: Fein Michael E. , Verdeyen J. T. , Cherrington B. E.
Published: January 2004

Power of 20 mW and gain of 11% have been obtained by using thermally excited nitrogen to pump a flowing-gas carbon dioxide laser. One immediate use of this new pumping technique is the study of molecular laser physics in a simplified environment; the thermal laser is essentially free of chemical and charged-particle effects.
OBSERVATION OF TUNABLE FOUR-PHOTON PARAMETRIC NOISE IN CALCITE
Authors: Meadors John G. , Kavage W. T. , Damon E. K.
Published: January 2004

We have observed tunable four-photon optical parametric noise in calcite with a Q-switched rubylaser pump. The observed radiation corresponds to the spontaneous emission from a phase-matched parametric system satisfying the relations: (1a) ω(ruby) + ω(ruby) = ω1 + ω2 and (1b) k0(ruby) + k0(ruby) = k1ε + k20, where ω and k denote the angular frequency and wavevector, respectively. The superscripts o and ε denote ordinary and extraordinary rays, respectively. The optical signal was tuned from 4300 to 5860 Å by adjusting the orientation of the calcite; this signal was detected by an RCA 7265 photomultiplier. Although no direct detection of the infrared signal was attempted, we would expect it to be tuned over the range from 0.843 to 1.80 μ. From experimental data, the estimated noise power in the high-frequency optical signal was about 0.5 μW.
IODINE HYPERFINE STRUCTURE OBSERVED IN SATURATED ABSORPTION AT 633 nm
Authors: Hanes G. R. , Dahlstrom C. E.
Published: January 2004

Hyperfine components of the R(127) line of the 11–5 band of molecular iodine at 633 nm have been observed by saturating the absorption inside the cavity of a single-frequency He–Ne laser. The component widths of 4.5 MHz were broadened a factor of 2 by 1-Torr iodine pressure, or by 500-G magnetic field. Since no wavelength shift as large as 2 MHz was observed, wavelength perturbations from these sources should be controllable to less than 2 × 10−13λ. The use of one of these components as a reference for laser stabilization is suggested.
PREPARATION OF LITHIUM FOR TRANSMISSION ELECTRON MICROSCOPY
Authors: Sass S. L.
Published: January 2004

Li foils for transmission electron microscopy were prepared by shaving a Li bar in a dry box under an Ar atmosphere. The specimen was transferred to the microscope using a modified Hitachi specimen exchange device. Li single-crystal diffraction patterns were observed. The microstructure consisted of small grains containing rapidly moving dislocations.
EFFICIENT DOPING OF GaAs BY Se+ ION IMPLANTATION
Authors: Foyt A. G. , Donnelly J. P. , Lindley W. T.
Published: January 2004

Efficient doping of GaAs by ion implantation has been obtained using Se+ ions. For a Se+ dose of 3 × 1012/cm2 implanted at 400 keV, a peak carrier concentration of 2 × 1017/cm3 occurred at a depth of 750 Å, with a standard deviation of 500 Å. Integration of the excess carrier concentration caused by the implantation indicates that for this ion dose at least 50% of the implanted ions are electrically active. For larger doses the doping efficiency decreases, and the carrier concentration approaches a limiting value of approximately 1019/cm3. The lowest observed sheet resistance for the implanted layer, about 250 Ω/square, occurred for a Se+ dose of 2 × 1014/cm2.
``LAMB DIP'' SPECTROSCOPY APPLIED TO SF6
Authors: Rabinowitz Paul , Keller R. , LaTourrette J. T.
Published: January 2004

Line centers of a number of previously unresolved SF6 transitions of the fundamental ν3 band have been observed and their frequencies have been determined relative to the P-branch transitions of the CO2 10.6-μ laser. Measurements of dip widths at small saturation levels yielded a determination of the SF6–SF6 cross section for phase interruption. Observation of a multiplicity of absorption line centers over the tuning range of the P(20) laser transition, several well within one SF6 Doppler width of 29 MHz, verifies the complex nature of the P(20) line absorption found by other workers.
MEASUREMENTS OF SUBNANOSECOND ``FILAMENT'' PULSES USING THE CONVOLUTION TECHNIQUE
Authors: Loy Michael M. T. , Shen Y. R.
Published: January 2004

The well-known convolution technique was used to measure subnanosecond pulses generated from ``filaments'' in a self-focused beam. The results showed that in toluene, the pulse width varied from 200 to 100 psec or less, and the peak power was about 30 kW.
ELECTRON DENSITIES AND TEMPERATURES IN A CLOSE-SPACED CESIUM PLASMA DIODE
Authors: Reichelt W. H.
Published: January 2004

Spectrographic techniques have been used to determine electron temperatures and densities in the interelectrode plasma of a close-spaced high-current cesium plasma diode. These results were obtained from the relative intensity of the radiative recombination continuum and measured line-widths, respectively, of cesium. The diode was operated at two short-circuit current conditions (∼15 and 18 A/cm2) with an interelectrode spacing of 0.25 mm. Contrary to some theories, these results indicate that steep temperature gradients do exist in the plasma and that maximum electron temperatures are 2800°K.
CHARGE STORAGE MODEL FOR VARIABLE THRESHOLD FET MEMORY ELEMENT
Authors: Sewell F. A. , Wegener H. A. R. , Lewis E. T.
Published: January 2004

A simple two-layer model is presented for charge storage in a MI2I1S device in which the times for charging and discharging are expressed in closed-form expressions depending on the conduction properties, the thicknesses, and the dielectric constants of the two layers. Data were taken using silicon oxide for I1 and silicon nitride for I2 which are in good agreement with the model. The model is quite general and should be valid for other insulators and other conduction mechanisms.
ROTATIONAL RELAXATION RATE OF CO2 LASER LEVELS
Authors: Cheo P. K. , Abrams R. L.
Published: January 2004

The rotational relaxation rate constant krot of the CO2 00°1 upper laser level has been determined by observation of the transient change in the cw gain of a 9.6-μ P(20) laser amplifier induced by passage of a 20-nsec 10.6-μ P(20) laser pulse through the amplifier.
IMPROVED CdTe FOR GAMMA DETECTION BETWEEN −100°C AND + 100°C
Authors: Zanio Kenneth R.
Published: January 2004

Mobility-trapping time μτ+ products of 2 × 10−4 cm2/V for electrons and 3 × 10−5 cm2/V for holes have been found in semi-insulating cadmium telluride using transient response techniques. This represents a tenfold and fourfold increase in the μτ+ product of holes and electrons, respectively. The 60Co response of surface barrier devices fabricated from this material indicates that gamma detection is possible over the extended temperature range of −100° to +100°C. Encapsulation techniques have been developed to prevent the degradation of these devices from the ambient atmosphere.
CURRENT OSCILLATIONS IN Si p-i-n DEVICES AFTER IRRADIATION WITH ONE-MeV ELECTRONS
Authors: Streetman B. G. , Holonyak N. , Krone H. V. , Compton W. Dale
Published: January 2004

Current oscillations similar to those previously reported in various semiconductors with impurity-induced traps have been observed in Si irradiated at 0°C with 1-MeV electrons. The oscillations are altered by annealing of the devices at temperatures below 0°C.
EPR DETECTION OF TRIPLE Li ION CENTERS IN LITHIUM-DIFFUSED Mn DOPED GaP CRYSTALS
Authors: Title R. S. , Plaskett T. S.
Published: January 2004

The presence of triple lithium ion centers (LiGa− 2Lii+)+ in lithium-diffused GaP crystals previously doped with Mn is inferred from combined electron paramagnetic resonance (EPR) and electrical data.
EVIDENCE FOR SPACE CHARGE LIMITED IONIC TRANSPORT AT THE SILVER CHLORIDE-AQUEOUS SOLUTION INTERFACE
Authors: Hoyen H. A. , Strozier J. A. , Li Che-Yu
Published: January 2004

Alternating current conductance and capacitance measurements are made on aqueous solution-silver chloride-aqueous solution couples as a function of frequency. The frequency dependence of the measured conductance and capacitance is found to agree with the calculated results based on a space-charge-limited ac conduction model.
UNEXPECTED EFFECTS OF FORCED HIGH NUCLEATION DENSITIES BY FLASH EVAPORATION OF GOLD ON NaCl and KCl SUBSTRATES
Authors: Henning C. A. O. , Lombaard J. C. , Botha J. C.
Published: January 2004

Gold was deposited slowly and simultaneously on air-cleaved NaCl and vacuum-cleaved NaCl and KCl crystals, portions of which had been covered with about 20 Å of gold by simultaneous flash deposition prior to the commencement of slow deposition 320°C substrate temperature. The epitaxy of gold on vacuum-cleaved NaCl substrates is enhanced by the higher nucleation density resulting from the flash deposition while the latter causes a deterioration of the epitaxy on both vacuum-cleaved KCl and air-cleaved NaCl substrates. It is proved that no effective substrate contamination results from the flash evaporation. It is suggested that a critical or epitaxial nucleation density exists for each deposit-substrate system.
MEASUREMENT OF PICOSECOND PULSE SUBSTRUCTURE USING COMPRESSION TECHNIQUES
Authors: Treacy E. B.
Published: January 2004

A grating pair, which is capable of detecting the quadratic phase term (linear frequency sweep) and compressing the ultrashort pulses from a mode-locked Nd-glass laser has been used in conjunction with second harmonic generation techniques to reveal a periodic wobble of the consecutive pulse envelopes. An asymmetry in the picosecond pulse envelope has been detected by scanning the pulses with their compressed counterparts in a fluorescing dye cell excited by two-photon absorption.
THERMIONIC-FIELD RESISTANCE MAXIMA IN METAL-SEMICONDUCTOR (SCHOTTKY) BARRIERS
Authors: Crowell C. R. , Rideout V. L.
Published: January 2004

A maximum in the differential resistance versus applied bias relationship of metal-semiconductor contacts is predicted to occur when current flow is predominantly by thermionic-field (thermally excited tunnel) emission. The predicted resistance peaks are generally asymmetrical with respect to voltage and may occur on either side of zero bias. The peak location has only an indirect correlation with the Fermi kinetic energy in the semiconductor. The theoretical approach is generally applicable to any metal-semiconductor system when the dominant carrier flux is associated with the tail of a Fermi-Dirac distribution. The theory is in reasonable agreement with recent experimental resistance measurements on Cr–Si Schottky barrier diodes at 77°K.
PHOTO-REVERSIBLE CHARGE TRANSFER IN RARE-EARTH-DOPED-CaF2
Authors: Staebler D. L. , Kiss Z. J.
Published: January 2004

Photoreversible absorption changes have been found in additively colored La-, Ce-, Gd-, or Tb- doped CaF2. Results are shown for one of these, Ce:CaF2, in which both the trivalent and divalent rare-earth absorptions are identifiable. These results suggest a charge transfer between the rare earth and a defect center produced by additive coloration.
MICROWAVE FREQUENCY ACOUSTIC SURFACE WAVE PROPAGATION LOSSES IN LiNbO3
Authors: Slobodnik A. J.
Published: January 2004

Deflection of laser light has been used to measure room-temperature acoustic surface wave propagation losses in LiNbO3 at both 1 and 2 GHz. In addition, surface wave delay lines operating at 1 GHz using fundamental frequency interdigital transducers and at 2 and 3 GHz using 3rd and 5th harmonic frequencies are described.
SOUND WAVE AMPLIFICATION IN INDIUM ANTIMONIDE
Authors: Route R. K. , Kino G. S.
Published: January 2004

We have directly measured acoustic wave amplification of shear waves in high mobility InSb in the frequency range 0.5–2.0 GHz. At 1 GHz we have observed 10 dB net terminal gain. We find good agreement with the modified theory of White in the high magnetic field region where the acoustic wavelength λ is much larger than the Larmor radius of the electrons. In the low magnetic field limit it is necessary to use the Boltzmann transport equation approach of Spector; in this case, good agreement with the observed behavior is obtained. This effect is shown to be responsible for the two-mode threshold behavior for acoustoelectric domain oscillations in InSb.
TIME BEHAVIOR OF EXCITON FORMATION AND LASER EMISSION IN Cd(SeS) PLATELETS
Authors: Keune D. L. , Rossi J. A. , Gaddy O. L. , Merkelo H. , Holonyak N.
Published: January 2004

Ultrathin (∼ 1 μm) Cd(SeS) platelets are excited with a mode-locked He–Ne laser and are shown to lase with a measured time delay of ∼ 10−9 sec. The measured delay agrees with the time required to redistribute optically generated electron-hole pairs uniformly through the sample thickness and to the proper density (1018/cm3) to form excitons.
EFFECT OF THE NON-EQUILIBRIUM CARRIERS ON THE TEMPERATURE HYSTERESIS OF THE PHASE TRANSITION IN SbSI
Authors: Grekov A. A. , Rodin A. I. , Fridkin V. M.
Published: January 2004

The illumination of the SbSI crystal in the range of its intrinsic photosensitivity results in the change of the temperature hysteresis value of the phase transition. This effect may be accounted for by the dependence of the surface energy of the nucleus of the new phase on the carrier density in the crystal.
ACOUSTIC SURFACE WAVE COUPLING ACROSS AN AIR GAP
Authors: Bond W. L. , Collins J. H. , Gerard H. M. , Reeder T. M. , Shaw H. J.
Published: January 2004

Transfer of acoustic surface waves between two noncontacting surfaces by means of passive, co-directional piezoelectric coupling is achieved in LiNbO3. Minimum coupling loss is less than 3 dB. When the surfaces are maintained parallel, periodic variation of insertion loss with coupling length is observed. Measurements are in close agreement with predictions using coupled mode theory. A 100-MHz delay line with a mechanically variable, nondispersive differential delay of 6.1 μsec and a total insertion loss less than 17 dB which utilizes this coupling mechanism is reported.
SUBPICOSECOND PULSE GENERATION USING THE OPTICAL KERR EFFECT
Authors: Fisher Robert A. , Kelley P. L. , Gustafson T. K.
Published: January 2004

A frequency modulation which is monotonic in time over a portion of an optical pulse can be utilized together with a dispersive delay line to obtain temporal compression of the pulse envelope. Short pulses (picosecond range) passed through an optical Kerr liquid receive a self-phase-modulation which exhibits a frequency sweep in the region of maximum intensity, the slope in time being proportional to the propagation distance. Frequency spreads of the order of 103 cm−1 are obtainable and hence significant compression ratios should be possible, giving rise to very short pulses in the range of 10−14 to 10−13 sec.
SPECTRAL CRITERION FOR MODE LOCKED LASER SIGNALS
Authors: Klauder John R.
Published: January 2004

A criterion for mode-locking of laser signals is presented that involves the signal spectrum and the intensity spectrum.
OBSERVATION OF FLUX DISTRIBUTIONS IN THIN FILM TYPE I SUPERCONDUCTORS OF VARYING THICKNESS
Authors: Barbee Troy
Published: January 2004

The variation of the flux structure with thickness in thin-film type I superconductors in perpendicular fields has been directly observed. As the film thickness decreases, the flux distribution varies from the intermediate state structure to a mixed state structure of multiply quantized flux lines.
REFLECTIVITY AND BAND STRUCTURE OF EuO
Authors: Grant P. M. , Suits J. C.
Published: January 2004

Near-normal incidence reflectivity of single-crystal EuO is reported for the energy range 1–9 eV. Results are interpreted in terms of recent band-structure calculations.
LOW TEMPERATURE ELECTROLUMINESCENCE
Authors: Dueker James E. , Glaenzer Richard H. , Saum George A.
Published: January 2004

Electroluminescent phosphors are used as the display portion of infrared image converters, operated at liquid-nitrogen temperature. These phosphors lose considerable brightness upon cooling, giving a dim display. This report demonstrates the sources of this brightness loss during cooling as (1) due to spectral shift to wavelengths less visible to the eye and (2) changes in dielectric constant of the binder during cooling, causing a decrease in effective electric field applied to the phosphor particles. Some improvement in brightness can be demonstrated by using very thin phosphor layers, thereby increasing the effective applied field.
RADIATIVE LIFETIMES IN n-TYPE GALLIUM ARSENIDE
Authors: Dingle R. , Rodgers K. F.
Published: January 2004

Radiative lifetimes and time-resolved spectra have been obtained for high-purity n-type gallium arsenide at low temperatures. The ∼ 1.51-eV bands, generally associated with the annihilation of free and bound excitons, decay very rapidly, τ < 15 nsec. The 1.49-eV band, variously described as donor-acceptor recombination or as a free-to-bound recombination, has a longer nonexponential decay. For this band, the time-resolved spectra show a steady shift to lower energy as the delay after the pulse is lengthened. The conclusion drawn is, that the 1.49-eV band arises from a D-A recombination process.
CONTINUOUS OPERATION OF A YAIG: Nd LASER BY INJECTION LUMINESCENT PUMPING
Authors: Allen R. B. , Scalise S. J.
Published: January 2004

Continuous operation of a YA1G:Nd laser has been achieved using incoherent injection luminescent pumping. GaAsxP1−x light-emitting diodes are used at liquid-nitrogen temperatures to provide effective optical pumping of YA1G:Nd over a narrow wavelength range. Initial experiments give a continuous laser output of 40 mW at 1.0641 μm with 8-W total electrical input power to the diodes.
NEGATIVE RESISTANCE IN GaP ELECTROLUMINESCENT DIODES
Authors: Bhargava R. N.
Published: January 2004

Negative resistance in red and green GaP electroluminescent diodes is observed. In both kinds of diodes deep-donor oxygen is shown likely to be responsible for the negative resistance.
GaAs SCHOTTKY BARRIER AVALANCHE PHOTODIODES
Authors: Lindley W. T. , Phelan R. J. , Wolfe C. M. , Foyt A. G.
Published: January 2004

Uniform avalanche Schottky barrier photodiodes have been fabricated by plating a thin layer of platinum on GaAs and forming a guard ring by proton radiation. Operating at a gain of 100 these photodiodes exhibit gain-bandwidth products greater than 50 GHz and enhanced signal to noise ratio in excess of 30 dB. The observed variation on the spectral response with bias can be accounted for by a change in the absorption of the Schottky barrier diode.
DISTORTION OF A CHOLESTERIC STRUCTURE BY A MAGNETIC FIELD
Authors: Meyer Robert B.
Published: January 2004

An experiment is described which confirms the theory of the distortion of a cholesteric structure by a magnetic field. Field effects in a sample of p-azoxyanisole doped with cholesteryl acetate were viewed directly with a microscope, and the pitch of the helical structure was measured as a function of field strength.
SPATIAL DISTRIBUTION OF 0.30 – 0.54 eV GASEOUS ARGON ATOMS SCATTERED FROM A SOLID ARGON SURFACE
Authors: Brown R. F. , Caldwell R. L. , Busby M. R.
Published: January 2004

A high-temperature aerodynamic molecular-beam apparatus has been used to investigate the spatial distributions of argon atoms scattered from solid argon at 15°K for incident energies of 0.30 to 0.54 eV and incident angles of 0 to 70 deg. A highly nondiffuse flux of scattered atoms was observed for the noncondensing atoms.
ION IMPLANTATION DAMAGE OF SILICON AS OBSERVED BY OPTICAL REFLECTION SPECTROSCOPY IN THE 1 TO 6 eV REGION
Authors: Kurtin Stephen , Shifrin Gordon A. , McGill T. C.
Published: January 2004

Optical reflection spectra of crystalline, sputtered, and ion implanted silicon specimens are presented. Characteristic aspects of the spectra of ion implanted specimens are related to lattice damage.
CHANGES OF OPTICAL REFLECTIVITY (1.8 TO 2.2 eV) INDUCED BY 40 - keV ANTIMONY ION BOMBARDMENT OF SILICON
Authors: Hart R. R. , Marsh O. J.
Published: January 2004

We have measured the fractional change in the optical reflectivity of silicon in the 1.8–2.2 eV photon energy band as a function of 40-keV antimony ion dose (1011–1015 Sb/cm2 at various implant temperatures (− 160–405°C). Approximate agreement is found between the change of reflectivity and previous measurements of lattice disorder as determined by backscattering of 1-MeV He ions.
CALCULATIONS OF TWO-PHOTON CONDUCTIVITY IN SEMICONDUCTORS
Authors: Yee Jick H.
Published: January 2004

The photoconductivity produced in some direct-band-gap semiconductors by the two-photon absorption process is investigated theoretically and found to be a very complicated function of the crystal parameters, the excitation photon energy, and the light excitation intensity. An application of the theory to a GaAs crystal is carried out.
CONTINUOUS INFRARED PARAMETRIC AMPLIFICATION IN A SATURABLE ABSORBER
Authors: Gordon P. L. , Schwarz S. E. , Shank C. V. , Wood O. R.
Published: January 2004

Continuous parametric amplification of signals near 10.6 μ has been obtained. Amplification is caused by interaction with a strong pumping beam in sulfur hexafluoride gas, a saturable absorber. Nonlinear polarization of individual SF6 molecules is considered to be responsible.
ELECTRON ENERGY DISTRIBUTION FUNCTIONS AND VIBRATIONAL EXCITATION RATES IN CO2 LASER MIXTURES
Authors: Nighan William L. , Bennett John H.
Published: January 2004

The electron energy distribution function has been calculated for the plasma of a CO2–N2–He mixture using available electron—molecule cross-section data. Rates at which electrons transfer energy to the inelastic levels of CO2 and N2 were then determined. With this information, the relationship of the various electron—molecule energy exchange processes to laser performance was studied. For conditions typical of CO2 lasers, approximately 17% of the power transferred to the CO2 and N2 was found to be available for conversion to optical power. Estimates of maximum available optical power were made and found to be consistent with experimental values.
SILICON (111) 7×7 STRUCTURE
Authors: Ridgway J. W. T. , Haneman D.
Published: January 2004

The Si(111) 7 × 7 structure has been observed within 9 sec of cleaving Si crystals at 850°C. Analysis shows that sufficient Fe to be regarded as essential for the structure cannot diffuse from the bulk in the time, although Li or Cu could. Sufficient contamination to form 1% of a monolayer could form by surface diffusion from the crystal sides, provided surface diffusion coefficients considerably greater than 5 × 10−5 cm2 sec−1 at 750°C were applicable.
HIGH-POWER AND HIGH-EFFICIENCY GaAs AVALANCHE DIODES
Authors: Kim C. , Armstrong L. D.
Published: January 2004

New high cw power and high-efficiency operations of GaAs avalanche diodes operating in the normal mode are reported. An output power of 500 mW (cw) at 11.1 GHz with an efficiency over 11.5% was obtained from a zinc-diffused GaAs diode. The diode was mounted junction side adjacent to the heat sink in a coaxial pin-type microwave package (Micro State Type 8).
DIFFUSION ANOMALIES IN THIN METALLIC FILMS
Authors: Selikson Bernard
Published: January 2004

The absence of void formation at the interface of aluminum-gold thin-film diffusion couples after diffusion annealing is noted in studies reported here. This is in contrast to the void formation observed in bulk aluminum-gold couples. The Kirkendall-effect explanation is believed not applicable to these thin-film samples where it is proposed that the rapid surface diffusion replenishes the formed vacancies, thus preventing vacancy condensation and void formation.
PHOTOLUMINESCENCE AND STIMULATED EMISSION IN Cd3P2
Authors: Bishop S. G. , Moore W. J. , Swiggard E. M.
Published: January 2004

Optically excited recombination radiation is observed in n-type single crystals of the II–V compound Cd3P2. Line narrowing characteristic of stimulated emission is induced at high excitation intensities.
ORIGIN OF FIELD-DEPENDENT COLLECTION EFFICIENCY IN CONTACT-LIMITED PHOTOCONDUCTORS
Authors: Caywood J. M. , Mead C. A.
Published: January 2004

It has been established that diffusion of photogenerated carriers into the electrode can be an important limitation of the collection efficiency of surface-barrier-limited photoconductors.
ELECTRO-OPTIC CHARACTERISTICS OF CdTe AT 3.39 AND 10.6μ
Authors: Kiefer James E. , Yariv Amnon
Published: January 2004

The physical characteristics of high resistivity CdTe which are relevant to its use for electro-optic modulation have been investigated at 3.39 and 10.6 μ. The unclamped electro-optic characteristic n0 3r41 of CdTe was found to be 12 × 10−11 m/V and the absorption coefficient is 0.006 cm−1. Our measurements indicate that CdTe will be a very important material for electro-optic modulation in the infrared.
HOLOGRAPHIC CONTOURING VIA MULTIFREQUENCY LASERS
Authors: Heflinger L. O. , Wuerker R. F.
Published: January 2004

Holographic images covered with range contours were produced by the multifrequency emission of a pulsed ruby. The multifrequency emission arises from the use of a resonant output reflector in the laser cavity, producing contour intervals equal to the optical thickness of the resonator. Intervals of about 1 cm and greater are attainable.
THE STRUCTURES OF GOLD FILMS GROWN ON CHLORIDE, HYDROXIDE AND BICARBONATE SURFACES OF ROCKSALT CRYSTALS
Authors: Henning C. A. O. , Vermaak J. S.
Published: January 2004

Air- and vacuum-cleaved rocksalt crystals have been treated with H2O vapor and with a mixture of H2O vapor and CO2 gas in order to study the influence of such contaminations on the epitaxial growth of gold films on NaCl crystals. Hydroxide surfaces resulting from the treatment with pure H2O vapor yielded epitaxial gold films on both vacuum- and air-cleaved specimens and these were very similar in nature to those epitaxial films normally grown on air-contaminated NaCl substrates. Bicarbonate surfaces resulting from the further treatment with a mixture of H2O vapor and CO2 gas yielded polycrystalline gold films on both the air- and vacuum-cleaved specimens.
IMPROVED RED AND INFRARED LIGHT EMITTING AlxGa1−xAs LASER DIODES USING THE CLOSE-CONFINEMENT STRUCTURE
Authors: Nelson H. , Kressel H.
Published: January 2004

AlxGa1−xAs injection lasers have been fabricated over the compositional range in which the alloy has a direct bandgap transition (0 < x ≤ 0.34). At 300°K the threshold current density increases with x from 12 000 A/cm2 (λL = 8600 Å) to 56 000 A/cm2 (λL = 7340 Å) in uncoated devices with cavity lengths of about 10 mils. In the same range of x the external differential quantum efficiency gradually decreases from 40 to 16%. These are the highest efficiencies and lowest threshold current densities ever reported for room-temperature lasers emitting in the same spectral range. The improvement is due to utilization of the new p+-p heterojunction structure previously used by the authors in GaAs lasers to sharply reduce the internal optical loss by improving the optical confinement and reducing the absorption coefficient in the p+ material adjoining the active region. At 77°K lasing has been achieved to 6450 Å and cw operation to 6900 Å with the emission of 0.4 W per diode.
DIODES IN SILICON CARBIDE BY ION IMPLANTATION
Authors: Dunlap H. L. , Marsh O. J.
Published: January 2004

We report here the formation of n-type layers with ion-implanted nitrogen or antimony in p-type α-SiC requiring maximum process temperatures of 1400 and 1600°C respectively for only a few minutes. This is believed to be the first confirmation of donor behavior by antimony in SiC. Electrical characteristics of these implanted layers have been evaluated by Hall and sheet resistivity measurements. Junction devices formed from the implanted layers have shown excellent forward and reverse characteristics at operating temperatures to 400°C.
TEMPORAL ASPECTS OF THE SELF-FOCUSING OF OPTICAL BEAMS
Authors: Fleck J. A. , Kelley P. L.
Published: January 2004

Numerical solutions are presented for a time-dependent two-dimensional wave equation in which the nonlinear contribution to the refractive index is governed by a relaxation equation. For input pulse widths comparable to the relaxation time, pulse shapes are asymmetrically distorted and self-focusing is inhibited but there is no indication of beam size stabilization.
DF–CO2 AND HF–CO2 CONTINUOUS-WAVE CHEMICAL LASERS
Authors: Cool Terrill A. , Falk Theodore J. , Stephens Ronald R.
Published: January 2004

Continuous-wave chemical laser operation has been observed at 10.6 μ in CO2 pumped by vibrational energy released from chemical reactions forming excited DF and HF molecules. A two-step vibrational energy transfer mechanism is proposed to explain the pumping of CO2 by chemically formed HF. The results suggest improved performance occurs when simple chain reactions are operative.
THE PREPARATION AND PROPERTIES OF VAPOR-DEPOSITED SINGLE-CRYSTAL-LINE GaN
Authors: Maruska H. P. , Tietjen J. J.
Published: January 2004

Single-crystalline, colorless, GaN has been prepared by a vapor-phase growth technique previously used to prepare GaAs, GaP, and GaSb. These crystals are the first reported speciments of GaN suitable for good electrical and optical evaluation of this compound. It has been determined that GaN has a direct energy bandgap of 3.39 eV, and that undoped crystals prepared by this method have a very high inherent electron concentration, typically above 1019/cm3, which is probably related to a high density of nitrogen vacancies. Conducting p-type specimens have been prepared using Ge as the dopant; but this result has been difficult to reproduce, and the samples have been electrically inhomogeneous.
CHEMICAL LASER ACTION IN ELECTRICALLY PULSED FLOWING CS2–O2 MIXTURES
Authors: Arnold S. J. , Kimbell G. H.
Published: January 2004

Laser action was achieved in spark-excited CS2–O2 mixtures at pressures of the order of 1 mm. The laser emission, in the region 5.0 to 5.3 μ, is attributed to CO, a product of combustion. It is suggested that the mechanism responsible for forming the excited CO is CS + O2 = CO + SO.
CONTINUOUS PASSIVE MODE LOCKING OF A CO2 LASER
Authors: McCoy John H.
Published: January 2004

An optical delay line is used to form a 45-m-long CO2 laser cavity. Continuous locking of the longitudinal cavity modes has been observed with SF6 or BCl3 in the cavity. The laser output is a continuous train of uniform amplitude pulses occurring at 300-nsec intervals. The observed pulse widths of 60–70 nsec correspond to locking five or six modes in a 13- to 18-MHz bandwidth.
EFFECT OF MOLECULAR DISSOCIATION AND VIBRATIONAL EXCITATION ON ELECTRON ENERGY TRANSFER IN CO2 LASER PLASMAS
Authors: Nighan William L.
Published: January 2004

The electron energy distribution function has been calculated for CO2 laser plasmas in gas mixtures of CO2, N2, and He using available cross-section data. Electron-molecule energy exchange rates were then calculated and used to evaluate the role of dissociation products in electron energy exchange processes. Under circumstances typical of CO2 lasers, the calculation shows that more than 15% of the electron energy can be transferred to CO vibrational levels. The sensitivity of electron kinetic processes to vibrational temperature variations was also evaluated for plasma systems dominated by N2. Changes in vibrational temperature were found to have a relatively small effect on electron power transfer.
LEED STUDY OF THE EPITAXIAL GROWTH OF Au ON PbS (100) SURFACE
Authors: Hanawa Teruo , Takeda Kenjiro
Published: January 2004

LEED study of Au films deposited on cleaved surfaces of PbS at above 200°C showed the existence of a monolayer of Au oriented parallel to the substrate. The interatomic distance of Au in the monolayer was derived to be about 1.5% less than its bulk value under the assumption that the surface lattice of PbS took the same dimension as the bulk lattice. The deposits were also examined by the conventional reflection HEED and electron microscopy.
HOT ELECTRON EMISSION FROM SILICON INTO SILICON DIOXIDE BY SURFACE AVALANCHE
Authors: Poirier R. , Olivier J.
Published: January 2004

Measurement of the MOS capacitance versus voltage by a fast voltage ramp has shown the avalanche effect in silicon surfaces. When avalanche occurred, emission of electrons into silicon dioxide and trapping effects were made possible.
NEGATIVE DIFFERENTIAL MOBILITY IN INDIUM ANTIMONIDE
Authors: Fawcett W. , Ruch J. G.
Published: January 2004

A Monte Carlo method has been used to calculate the velocity-field relationship for n-type indium antimonide at 77°K. Although a negative differential mobility due to the nonparabolicity of the (000) valley is predicted in agreement with previous theories, it is shown that the transfer of electrons to the 〈 111 〉 valleys produces a much larger negative differential mobility at lower electrical field strengths.
MEASUREMENT OF THE PHENOMENOLOGICAL ENERGY RELAXATION TIME IN n-Si AT 77°K LATTICE TEMPERATURE
Authors: Holm-Kennedy James W. , Champlin K. S.
Published: January 2004

We report the measurement of the phenomenological energy relaxation time for n-Si at a lattice temperature of 77°K as a function of applied dc electric field. The computation is made using the dc current-voltage characteristic of a sample oriented in the 〈111〉 crystallographic direction. The carriers in the ``warm'' electron region are assumed to be described by a Maxwellian distribution.
OPTICAL AND X-RAY INTERFEROMETRY OF A SILICON LATTICE SPACING
Authors: Deslattes Richard D.
Published: January 2004

A device permitting simultaneous x-ray and optical interferometry over traverses in excess of 20 μm is reported. Results obtained to date suggest that such devices will permit measurements of certain crystal-lattice spacings with accuracies better than one part per million.
OPTICAL SECOND-HARMONIC GENERATION IN CRYSTALS OF ORGANIC DYES
Authors: Bass M. , Bua D. , Mozzi R. , Monchamp R. R.
Published: January 2004

Optical second-harmonic generation has been observed in crystals of six organic dyes. One dye, 7-diethylamino-4-methylcoumarin, appears to be at least as good a frequency doubler as LiNbO3 and has a much higher resistance to surface damage.
EXTENSION OF LASER HARMONIC-FREQUENCY MIXING TECHNIQUES INTO THE 9 μ REGION WITH AN INFRARED METAL-METAL POINT-CONTACT DIODE
Authors: Daneu V. , Sokoloff D. , Sanchez A. , Javan A.
Published: January 2004

An infrared point-contact diode is used to mix the frequency of a 28.0 μ water laser with that of a 9.3 μ CO2 laser and a K-band microwave radiation. The experiment provides, among several applications, the crucial link necessary to establish a frequency multiplier chain for absolute frequency measurements in the infrared.
FORMATION OF EPITAXIAL β-SiC FILMS ON SAPPHIRE
Authors: Khan I. H. , Learn Arthur J.
Published: January 2004

Epitaxial β-SiC films have been formed on sapphire by chemical conversion of thin single-crystal Si-on-sapphire films. The conversion is obtained by reaction of C2H2 with Si within the temperature range 900–1200°C. It is observed that epitaxy persists up to a certain depth, beyond which film orientation degenerates. The growth morphology of the β-SiC films appears to be related to surface granularity of the Si films and differs from that observed for conversion of bulk Si.
TWO CAVITY MODE-LOCKING OF A He–Ne LASER
Authors: Allen L. B. , Rice R. R. , Mathews R. F.
Published: January 2004

Complete mode-locking of a He–Ne laser has been achieved using an electro-optic phase modulator driven at the c/2L frequency of the laser cavity and situated near one end of a passive cavity which was strongly coupled to the active cavity. This technique permits the use of modulator crystals which are too lossy for intracavity operation and results in shorter pulses than can be obtained with conventional intracavity techniques.
THREE-FREQUENCY HETERODYNE SYSTEM FOR ACQUISITION AND TRACKING OF RADAR AND COMMUNICATIONS SIGNALS
Authors: Teich M. C.
Published: January 2004

The operation of a three-frequency heterodyne system for communications and radar use is discussed. The technique provides important advantages over the conventional heterodyne detector, and is applicable in the infrared, optical, and microwave. The signal-to-noise ratio and minimum detectable power for the specific case of an optical or infrared system are calculated and compared with values for the standard configuration. A practical CO2 laser radar has been examined as a particular example of this mode of operation.