bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-threshold LPE In1−x′Gax′P1−z′ Asz′/In1−xGaxP1−zAsz/In1− x′ Gax′P1−z′Asz′ yellow double-heterojunction laser diodes (J<104 A/cm2, λ∼5850 Å, 77 °K)
Authors: Hitchens W. R. , Holonyak N. , Wright P. D. , Coleman J. J.
Published: February 2003

Liquid phase epitaxial (LPE) In1−x′Gax′P1−z′ Asz′/In1−xGaxP1−zAsz/In1− x′ Gax′P1−z′Asz′ (x′∼0.66, z′∼0.005; x∼0.71, z∼0.10) double-heterojunction laser diodes that operate in the yellow at relatively low current densities (J<104 A/cm2, λ∼5850 Å, 77 °K) are reported. The lattice-matched LPE quaternary growth process, employing GaAs1−yPy substrates, and the double-heterojunction laser diode properties are described.
Ultrafast guided-light beam deflection/switching and modulation using simulated electro-optic prism structures in LiNbO3 waveguides
Authors: Tsai C. S. , Saunier P.
Published: February 2003

Theoretical and experimental results on new guided-wave electro-optic devices for ultrafast optical deflection, switching, and modulation are presented. The devices utilize simple electrode arrangements consisting of a small number of tilted electrodes which effectively simulate prism structures in electro-optic waveguides. Devices using single-mode Y-cut LiNbO3 outdiffused waveguides have demonstrated excellent performance figures: nine beam positions (channels) per unit at a driving voltage of 8 V per beam position, −0.5 dB optical insertion loss and cross talks between adjacent channels varying from −13.5 to −9 dB. The new devices are shown to be capable of performing optical multiport beam deflection/switching and modulation at very low driving voltages and at ultrafast speeds because of their very small capacitances, and are, therefore, highly useful for future wide-band fiber and integrated optic systems.
Hole conduction and valence-band structure of Si3N4 films on Si
Authors: Weinberg Z. A. , Pollak R. A.
Published: February 2003

Transport measurements were performed on thin films of Si3N4 deposited on Si using carrier injection from low-energy corona ions and a shallow junction detector. Large hole conduction is found for both corona polarities. Examination of the electronic structure of Si3N4 by x-ray photoemission spectroscopy (XPS or ESCA) reveals one broad structure 10 eV wide (FWHM) at the top of the valence bands which results from the bonding of the Si 3s, Si 3p, and N 2p orbitals. This finding is consistent with the hole conduction we observe. The XPS results are compared with those from amorphous SiO2. The tops of the valence band of Si3N4 and SiO2 are found to lie 1.5±0.2 eV and 4.5±0.2 eV, respectively, below the Fermi level of a thin overlayer of gold.
Semiconductor-electrolyte photovoltaic cell energy conversion efficiency
Authors: Chai Y. G. , Anderson W. W.
Published: February 2003

Photocurrent and differential capacitance were measured as a function of terminal potential with CdS- and GaAs-electrolyte photovoltaic cells to determine the open-circuit voltage Voc and the power conversion efficiency ηp. Voc was found to be 1.2 V for both cells. With monochromatic excitation, ηp=32% for the CdS cell, and ηp=21% for the GaAs cell. For both cells the quantum efficiency was larger than unity at short wavelengths indicating that current doubling is occurring at the interface. For the GaAs cell, current flow is mostly due to the diffusion of minority carriers from the bulk to the space-charge layer under illumination.
Statistics in laser-induced dielectric breakdown
Authors: Boling N. L. , Bräunlich P. , Schmid Ansgar , Kelly Paul
Published: February 2003

The statistical aspects of laser-induced breakdown of transparent dielectrics are reexamined and it is found that the experimentally observed independence of the damage probability on spot size is inconsistent with previous theory. In an attempt to find spot-size-independent contributions to damage statistics, modification of the electronic properties of the material caused by intense photon fluxes below the one-shot damage threshold is considered. This modification takes the form of absorbing defects (color centers). The case of high-quality NaCl (containing 5×1016 Cl− vacancies) is discussed in detail. At the ruby frequency, it may require up to three identical 60-nsec shots at the same sample site to cause damage at field strengths below the one-shot threshold. The results exhibit the proper volume dependence and they indicate that laser-induced material modifications prior to breakdown may indeed contribute to damage statistics.
Strength of fiber optical waveguides
Authors: Maurer Robert D.
Published: February 2003

Optical waveguides must withstand tensile stresses over kilometers of length where one flaw can be fatal. The strength of long lengths has not been previously studied but this paper presents a few preliminary data and compares them with the more abundant data on short lengths. Weibull statistics provide the logical basis for this comparison. The same Weibull constants adequately describe the long-length data and the low-strength portion of the short-length data. Flaws in 10–100 km lengths, therefore, seem to be of the same class as those found in relatively short gage lengths.
High-frequency limitation of metal-insulator-metal point-contact diodes
Authors: Riccius H. D.
Published: February 2003

It is shown that for frequencies above 200 THz the antenna impedance is predominantly the surface impedance of the tungsten whisker. Because of the high surface resistance of the order of 104 Ω, the whisker can no longer act as an efficient receiving antenna.
Coherent integration and correlation in a modified acoustoelectric memory correlator
Authors: Ingebrigtsen K. A. , Stern E.
Published: February 2003

The storage, correlation, and coherent integration of analog signals in a Schottky diode acoustoelectric memory correlator is described. The experiments demonstrate storage of phase and amplitude of a 70-MHz signal by the distribution of charge in an array of Schottky diodes. Coherent integration is obtained by accumulating a succession of charges in highly resistive polycrystalline silicon islands. Coherent integration over a time period of several tens of milliseconds is reported.
A simple pulsed laser system tunable in the ultraviolet
Authors: Atkinson G. H. , Schuyler M. W.
Published: February 2003

A flashlamp-pumped dye laser, operating with a 55-nsec (FWHM) pulsed output, has been used in conjunction with a 90° phase-matched nonlinear optical crystal (ADA) to generate tunable radiation in the 290–300-nm region at power levels greater than 1 kW.
Third harmonic generation from laser-produced plasma
Authors: Baldis H. A. , Pépin H. , Grek B.
Published: February 2003

Third harmonic emission has been observed from a laser-created plasma, using a nanosecond TEA CO2 laser. The observed threshold for this emission is 6×1012 W cm−2.
Efficient electrical initiation of an HF chemical laser
Authors: Mangano J. A. , Limpaecher R. L. , Daugherty J. D. , Russell F.
Published: February 2003

Efficient electron-beam initiation of an atmospheric-pressure HF chain-reaction laser has been demonstrated. Intrinsic electrical efficiencies of up to 875% have been observed with laser output energy densities of up to 51 J/liter atm at low initiation levels. This result was obtained for a laser mixture containing H2:F2:He:O2 at mole fractions of 0.08:0.30:0.61:0.01. Laser output energy was extracted from a volume of 104 cm3.
Infrared molecular lasers pumped by electronic-vibrational energy transfer from Br(42P1/2): CO2, N2O, HCN, and C2H2
Authors: Petersen Alan B. , Wittig Curt , Leone Stephen R.
Published: February 2003

Infrared lasers pumped by electronic-vibrational (E-V) energy transfer are reported. Gas mixtures containing electronically excited Br atoms (2P1/2) are prepared by flash photolyzing Br2 in the presence of a polyatomic molecule. The ensuing E-V process is selective and pumps the polyatomic molecule into specific energy states. In addition to obtaining gain and/or stimulated emission at CO2 and N2O laser frequencies, we have obtained stimulated emission from HCN at 3.85, 7.25, and 8.48 μm, and from C2H2 in the region 7–8 μm. Extension of the principles involved to other polyatomic molecules is straightforward, and a number of applications are suggested by our results to date.
Model for the bleaching of WO3 electrochromic films by an electric field
Authors: Faughnan Brian W. , Crandall Richard S. , Lampert Murray A.
Published: February 2003

Measurements have been made of the current flow in amorphous WO3 films containing electrons and mobile cations. In a configuration in which electrons are extracted at one contact and cations at the other, the current decays as t−3/4 over many decades of time. By using space-charge current flow ideas, we develop a theory that gives the correct time dependence and magnitude of the current for this double-extraction phenomenon.
Holographic subtraction using anisotropic centers in alkali halide crystals
Authors: Schneider Irwin , Collins William C. , Marrone Michael J. , Gingerich Michael E.
Published: February 2003

Coherent partial holographic erasure and selective erasure of volume holograms is demonstrated using the linear record and erase capability of photodichroic crystals, i.e., alkali halides with anisotropic color centers.
Efficient GaAs1−xSbx/AlyGa1−yAs1−xSbx double heterostructure LED’s in the 1-μm wavelength region
Authors: Nahory R. E. , Pollack M. A. , Beebe E. D. , DeWinter J. C.
Published: February 2003

Double-heterostructure (DH) GaAs1−xSbx/AlyGa1−yAs1−xSbx electroluminescent diodes (LED’s) emitting in the 1-μm wavelength region have been prepared by liquid phase epitaxy. Total external efficiencies of 2% have been obtained in junction edge emission. These devices are considerably more efficient than GaAs1−xSbx homojunction LED’s grown in a similar manner.
Granular aluminum SQUID’s
Authors: Deutscher G. , Rosenbaum R.
Published: February 2003

Granular aluminum thin films have been used to produce rf-pumped SQUID’s. Owing to the low critical current density of the granular superconductors, SQUID’s with weak links as wide as 40 μm are observed to operate even far below Tc.
Pyroelectric response to infrared radiation signals at the F
R(LT)-F
R(HT) transition in lead titanate-zirconate
Authors: Zeyfang R. R. , Sehr W. H. , Kiehl K. V.
Published: February 2003

Pyroelectric voltage transients obtained from modified Pb(Ti0.07Zr0.93)O3 ceramics in response to step ir signals were studied between 20 and 100 °C, in which range the FR(LT)-FR(HT) transition occurs. The temperature dependences of peak voltage and total released charge exhibit a pronounced peak at about 85 °C with a small temperature hysteresis indicating that this transition is not purely of second order. The pyroelectric coefficient between room temperature and the transition temperature increases by about a factor 10. The dynamical behavior and the dielectric properties are discussed and their potential for the development of ir devices operating at or near this phase transition is outlined.
Diffusion of iron ions in a cold liquid: Evidence against a ’’jump’’ model
Authors: Ruby S. L. , Love J. C. , Flinn P. A. , Zabransky B. J.
Published: February 2003

We take macroscopic (x-ray attenuation) and microscopic (Mössbauer line broadening) measurements of ions diffusing in a cold liquid. Combined, the results demonstrate that jumps the size of lattice dimensions do not take place, in contrast to crystalline diffusion. Surprisingly from molecular dynamical considerations, D is Arrhenius-like over four decades.
Laser emission at 1.32 μm from atomic iodine produced by electrical dissociation of CF3I
Authors: Pleasance L. D. , Weaver L. A.
Published: February 2003

Laser emission on the I(2P1/2) →I(2P3/2) transition at 1.32 μm has been excited for the first time in an electrical discharge. A mixture of about 1% CF3I in N2 was excited in a uv-initiated pulsed dicharge between planar electrodes. Iodine atoms in the upper and lower laser levels are generated by dissociative excitation of CF3I molecules upon electron impact. The lower laser level is depopulated by rapid recombination of the iodine atoms.
Surface-wave correlation and time scaling in a structure of Bi12GeO20-Si-LiNbO3
Authors: Wang W. C. , Meng K. S.
Published: February 2003

Surface-acoustic-wave correlation of two signals has been performed by using space-charge nonlinearity in a layered structure of Bi12GeO20-Si-LiNbO3. The two surface waves are collinear and propagate in the same direction. The same structure has also been used in a different mode of operation to perform the functions of convolution and time scaling.
The use of electronic space charge to accelerate, focus, and bunch ions for pellet fusion
Authors: Verdeyen J. T. , Swanson D. A. , Cherrington B. E. , Johnson W. L.
Published: February 2003

Theoretical arguments are presented which show that electronic space charge can transfer large amounts of energy to ions while simultaneously focusing and bunching their arrival at a small pellet.
A new luminescence line due to nitrogen implanted into AlxGa1−xAs (x=0.37)
Authors: Gonda Shun-ichi , Makita Yunosuke
Published: February 2003

Optical behavior of isoelectronic impurities in AlxGa1−xAs (x=0.37) is investigated. Photoluminescence of the samples implanted with N was measured at 2 °K. A new luminescence line is observed at an energy which is 90 meV below the edge emission peak. The integrated intensity of the N-implanted sample is about five times larger than that of an unimplanted and annealed sample. This is thought to be due to the bound states produced by the N atoms which replace the As atoms.
Picosecond optical detection by high-speed sampling of photoelectrons
Authors: Wiczer James J. , Merkelo Henry
Published: February 2003

It is demonstrated that photoelectrons distributed in initial velocity can be extracted from electrically broad-band configurations with extremely high time resolutions. Properties and values of parameters characterizing real materials and laboratory-generated electrical sampling signals are used throughout the analysis. These results provide the basis for the design of practical high-speed sampling photodetectors that can extend the resolution of incoherent low-level optical signals to a few picoseconds.
Photoresponse and barrier height of Pb-Pb oxide-Pb sandwich structures
Authors: Gundlach K. H. , Kadlec J.
Published: February 2003

The spectral dependence of the photocurrent in Pb-Pb oxide-Pb structures is investigated varying both the electrode thickness and the resistance of the junctions. The samples exhibit sign reversal of the photocurrent with changing photon energy hν. The effect is strongly controlled by the electrode thickness and direction of illumination. Zero-bias barrier heights betwen 0.8 and 1 eV have been deduced from the threshold of the photoresponse. Onset of band-to-band excitation in the oxide film has probably been observed at hν≃2.7 eV for thermally oxidized samples and at hν≃2.9 eV for plasma-oxidized samples.
Quantum interference Josephson logic devices
Authors: Zappe H. H.
Published: February 2003

Experiments with latching and nonlatching quantum interference logic devices are described. The device is a three-junction interferometer, switching with control currents of <0.5 mA. Simple logic functions have been performed with dc-powered nonlatching devices having a power dissipation of <40 nW in continuous operation.
354-nm laser action on XeF
Authors: Brau C. A. , Ewing J. J.
Published: February 2003

This letter reports laser action on the xenon monofluoride 2Σ1/2→2Σ1/2 band at 354 nm. Lasing on discrete vibrational bands has been achieved by pulse excitation of high-pressure mixtures of F2/Xe/Ar with an electron beam. XeF is a member of a new class of diatmoic molecules, the noble gas monohalides, which all exhibit similar molecular structure and spectra, and laser action should be attainable on the various bands of other members of this class of molecules. The kinetics and loss mechanisms of these laser candidates are briefly discussed.
External higher-index mode filters for band widening of multimode optical fibers
Authors: Furuya K. , Suematsu Y. , Nayyer J. , Ishikawa S. , Tagami F.
Published: February 2003

External higher-index mode filters were fabricated and their filter actions were confirmed experimentally. Loading the multimode fiber with the mode filter, the increase of the pulsewidth at the half-peak value was reduced from 640 to 130 ps, at the expense of loss penalty of 0.7 dB including the connection losses. These data suggest the effectiveness of mode filter insertion for band widening of multimode fibers.
Noise measurements in superconducting proximity bridges
Authors: Decker S. K. , Mercereau J. E.
Published: February 2003

Experiments and analsis have been done to show that the low-frequency noise voltage developed across a current-biased proximity-coupled superconducting bridge is well described by existing theories of electron tunneling. There is also some evidence that, on a two-fluid model, normal and supercurrent noise may be correlated. The temperature sensitivity of these bridges is calculated from the measured noise spectrum and is found to compare favorably with existing bolometric techniques.
Frequency conversion in a long Josephson junction with a moving vortex array
Authors: Yoshida K. , Irie F.
Published: February 2003

The dispersion relation of small electromagnetic waves applied in the uniform flux-flow state of a long Josephson junction has been obtained. The results contain exponentially growing waves due to the parametric interaction between the applied fields and the moving vortices, which indicates the possibility of a Josephson-junction frequency converter of the traveling-wave type.
Interface effects and high conductivity in oxides grown from polycrystalline silicon
Authors: DiMaria D. J. , Kerr D. R.
Published: February 2003

Several dark-current and photocurrent techniques have been used to determine the nature of high dark conductivity observed in oxides grown from polycrystalline silicon. Photocurrent measurements on polycrystalline Si-SiO2-Al MOS structures give idential interface energy barrier heights to those on single-crystal Si-SiO2-Al MOS structures, and do not show the presence of any measurable oxide charge. Dark-current measurements on polycrystalline Si MOS structures oxidized to varying degrees show an abrupt conductivity decrease when the polycrystalline Si is completely oxidized to the underlying single-crystal Si substrate. It is concluded from these experiments that the high dark conductivity observed is an interface phenomenon that is due to localized field enhancement near the injecting contact. This field enhancement, not being due to positive oxide charge, is speculated to be caused by surface asperities.
Magnetic properties of amorphous Gd-Co-Au films
Authors: Hasegawa R. , Gambino R. J. , Ruf R.
Published: February 2003

Magnetization as a function of temperature (4.2–300 °K) for the amorphous ferrimagnetic Gd-Co-Au alloys is analyzed by using a two-sublattice model. The magnetization behavior is discussed in terms of the cobalt spin value, and the intersublattice and intrasublattice exchange constants. Magnetic domain wall properties are considered in an attempt to estimate the growth-induced uniaxial perpendicular anisotropy.
Coupling characteristics of thin-film metal-oxide-metal diodes at 10.6 μ
Authors: Wang S. Y. , Izawa T. , Gustafson T. K.
Published: February 2003

Coherent coupling of 10.6-μm radiation into high-resistance photolithographically fabricated metal-oxide-metal tunnel junctions has been demonstrated in direct detection experiments.
Electron-beam-controlled discharge pumping of the KrF laser
Authors: Mangano J. A. , Jacob J. H.
Published: February 2003

Laser action has been obtained in atmospheric-pressure mixtures of 0.1% F2/2% Kr/97.9% Ar at 248.5 and 249.5 nm with electron-beam-controlled discharge pumping. The laser and discharge characteristics are explored as a function of discharge electric field and total mixture pressure. These preliminary measurements indicate laser output energies up to 6 mJ with a pulse length of 90 nsec. Limiting efficiencies for this laser system are discussed.
Coherent anti-Stokes Raman spectroscopy (CARS): Improved experimental design and observation of new higher-order processes
Authors: Chabay Ilan , Klauminzer Gary K. , Hudson Bruce S.
Published: February 2003

The development of the optical and electronic arrangement which has permitted the straightforward measurement of coherent anti-Stokes Raman spectra (CARS) and of higher-order processes not previously reported is described in this paper. The CARS spectrum of a dilute solution of diphenyloctatetraene in benzene is presented. This spectrum demonstrates the significantly greater signal-to-noise ratio possible with CARS as compared to conventional Raman techniques. Higher-order Raman spectral excitation studies (HORSES) are described which indicate the presence of a six-wave or a second-order four-wave mixing process.
Resonant tunneling through Schottky barriers
Authors: Helman J. S. , Sinencio F. Sánchez
Published: February 2003

The model of the Schottky barrier is based on the presence of ionized donors within the barrier. The empty energy levels corresponding to these donors lie in the barrier. Thus, there can be resonant tunneling through these empty energy levels. This is an inherent effect associated with Schottky barriers. We show how resonant tunneling depends on the ionization energy of the donors and the conditions under which resonant tunneling prevails over common tunneling.
Effective glow discharge excitation of nitrogen lasers at gas pressures ranging from 0 to 5 bar
Authors: Hasson V. , von Bergmann H. M. , Preussler D.
Published: February 2003

This paper applies a novel stabilization technique to the effective glow discharge excitation of uv nitrogen lasers at gas pressures ranging from 0 to 5 bar. The plasma is produced between uniform field electrodes and can be stabilized at electrode separations of down to 1 mm. The stabilization is relatively insensitive to the electrode geometry and surface finish. Megawatt pulses were obtained from a 25-cm atmospheric-pressure device energized by a simple flat-plate Blumlein circuit.
Continuous operation of 1.0-μm-wavelength GaAs1−xSbx/AlyGa1−yAs1−xSbx double-heterostructure injection lasers at room temperature
Authors: Nahory R. E. , Pollack M. A. , Beebe E. D. , DeWinter J. C. , Dixon R. W.
Published: February 2003

Double-heterostructure GaAs1−xSbx/AlyGa1−yAs1−xSbx injection lasers have been operated continuously at room temperature for the first time. Emission was near 1.0 μm. The lowest threshold current density observed was 2.1 kA  cm−2 dc.
A kilovolt picosecond optoelectronic switch and Pockel’s cell
Authors: LeFur P. , Auston D. H.
Published: February 2003

Photoconductivity produced by picosecond optical pulses in silicon has been used to switch electrical signals as large as 1.5 kV. The signals have been used to drive a traveling-wave Pockel’s cell for efficient optical switching with a measured rise time of approximately 25 psec.
Detection of nuclear quadrupole resonance via induced longitudinal magnetization
Authors: Jach Terrence
Published: February 2003

The first measurement of pure nuclear quadrupole splitting energies by monitoring the induced longitudinal magnetic moment has been carried out on a crystal of sapphire at 4.2 °K. Adiabatic fast passage was used to invert the populations of levels split by the quadrupole interaction. A small magnetic field removed the degeneracy of the nuclear states, allowing measurement of the linewidth and spin-lattice relaxation time. Unlike conventional techniques of adiabatic passage, this method, utilizing a SQUID magnetometer, allows determination of the widths of nuclear quadrupole lines without a sacrifice in signal level.
Photovoltaic properties of n-CdSe/p-ZnTe heterojunctions
Authors: Buch Fredrik , Fahrenbruch Alan L. , Bube Richard H.
Published: February 2003

Measurements of the diffusion potential, depletion layer width, and bias dependence of quantum efficiency for n-CdSe/p-ZnTe heterojunctions are used to construct a band diagram for the junction and to propose a current transport model. A new value of the electron affinity of CdSe is indicated by measurements of the open-circuit voltage at low temperatures and high intensities. The saturation current density J0 is controlled by a thermal activation energy of 0.8 eV, corresponding to electron flow to the interface where recombination occurs through interface states. Performance as photovoltaic cells is limited by the short diffusion length of holes in CdSe.
GaAs-Ga1-xAlxAs double-heterostructure injection lasers with distributed Bragg reflectors
Authors: Tsang Won-Tien , Wang Shyh
Published: February 2003

Laser oscillation in injection-pumped GaAs-Ga1−xAlxAs double-heterostructure distributed Bragg reflector (DBR) lasers is reported. Current threshold density as low as 890 A/cm2 in pulsed operation has been obtained at 183 °K. In this laser diode, the corrugations are placed outside the active part of the laser in the form of an end pair of parallel Bragg reflectors. The observed characteristics of the DBR lasers are found to agree well with the theory.
Red-light-emitting laser diodes operating cw at room temperature
Authors: Kressel H. , Hawrylo F. Z.
Published: February 2003

Heterojunction laser diodes of AlGaAs have been prepared with threshold current densities substantially below those previously achieved at room temperature in the 7200–8000-Å spectral range. These devices operate cw with simple oxide-isolated stripe contacts to 7400 Å, which extends cw operation for the first time into the visible (red) portion of the spectrum.
Spin-flip Raman laser at wavelengths up to 16.8 μm
Authors: Patel C. K. N. , Chang T. Y. , Nguyen V. T.
Published: February 2003

An InSb spin-flip Raman (SFR) laser is pumped with an optically pumped NH3 laser line at 780.515 cm−1 to obtain tunable first Stokes laser radiation at wavelengths up to 16.8 μm. We report results on the power output, tunability, and preliminary spectroscopy of UF6. Scaling of the primary CO2 pump laser as well as the NH3 laser together with the SFR laser appears possible for potential application of this system to uranium isotope separation.
Low-loss GaAs p+n−n+ three-dimensional optical waveguides
Authors: Leonberger F. J. , Donnelly J. P. , Bozler C. O.
Published: February 2003

Two types of low-loss single-mode p+n−n+ GaAs three-dimensional waveguides have been successfully fabricated and their attenuation coefficients measured. The devices are an optical stripline and a new device, the channel-stop strip guide. The channel-stop strip guides have losses of 0.8 cm−1 at 1.06 μm and 1.1 cm−1 at 0.920 μm; the losses for the optical striplines are 1.2 cm−1 at 1.06 μm and 1.7 cm−1 at 0.920 μm. A first-order loss calculation has yielded attenuation coefficients within 25% of these measured values. Both structures have an n+ substrate, an n− epitaxial layer for guiding, and p+ regions to laterally confine the light. The p+ regions have a uniform concentration and are formed by multiple-energy Be+-ion implantation; the p+n− junctions show sharp high-voltage breakdowns at average electric fields in the n− layer of 1.5×105 V/cm.
First phase nucleation in silicon–transition-metal planar interfaces
Authors: Walser R. M. , Bené R. W.
Published: February 2003

What is the first compound that nucleates in planar solid silicon–transition-metal binary couple reactions whose members form bulk equilibrium compounds? We propose, for couples annealed at low temperatures, the following simple rule: The first compound nucleated in planar binary reaction couples is the most stable congruently melting compound adjacent to the lowest-temperature eutectic on the bulk equilibrium phase diagram. The predictions of this rule are compared with experimental results.
High-power integrated optic ir modulator at microwave frequencies
Authors: Cheo P. K. , Gilden M.
Published: February 2003

Optical sideband power of 40 mW has been generated in a 25-μm-thick GaAs waveguide modulator at 16-GHz offset from a 4-W CO2 laser carrier by applying a microwave power of 20 W. The electrode is in the form of a microstrip transmission line, 2.8 cm long and 1 mm wide. The measured modulation bandwidth is 1 GHz at the sideband half-power points.
Attenuation of Rayleigh surface waves by surface roughness
Authors: Maradudin A. A. , Mills D. L.
Published: February 2003

We have carried out a calculation of the attenuation of Rayleigh surface waves by surface roughness, in the limit where the amplitude of the roughness is small. A Green’s function method has been employed in the work. In this letter, we present a summary of our method along with some principal results.
Attachment-dominated electron-beam-ionized discharges
Authors: Daugherty J. D. , Mangano J. A. , Jacob J. H.
Published: February 2003

In this letter we derive the stability criterion in discharges where two-step ionization is dominant. For stable equilibrium the attachment rate has to be greater than or equal to twice the ionization rate. Two-step ionization is often dominant in discharge-pumped visible lasers because of the relatively large number of electronically excited states. Analysis of the KrF laser discharge indicates that two-step ionization is dominant.
Magnetization reversal in GdCo5 single crystals
Authors: Katayama Toshikazu , Ohkoshi Masatoshi , Koizumi Yoshiaki , Shibata Tsugio , Tsushima Tachiro
Published: February 2003

The magnetic properties and the process of magnetization reversal in a bulk single-crystal sphere of GdCo5 were studied between 80 and 300 K. Numerous rectangular hysteresis loops were observed similar to observations made in small-particle experiments, and they are discussed in terms of the nucleation model and the pinning model.
Germanium-overcoated niobium Dayem bridges
Authors: Holdeman L. B. , Peters P. N.
Published: February 2003

Overcoating constriction microbridges with semiconducting germanium provides additional thermal conductivity at liquid-helium temperatures to reduce the effects of self-heating in these Josephson junctions. Microwave-induced steps were observed in the I-V characteristics of an overcoated Dayem bridge fabricated in a 15-nm-thick niobium film; at 4.2 K (Tc−T=2.6 K), at least 20 steps could be counted. No steps were observed in the I-V characteristics of the bridge prior to overcoating. In addition, the germanium overcoat can protect against electrical disturbances at room temperature.
High-power narrow-line pulsed 496-μm laser
Authors: Semet A. , Luhmann N. C.
Published: February 2003

The design and operation of a pulsed high-power narrow-line CH3F oscillator-amplifier laser system is described. The dielectric waveguide oscillator produces output in a single longitudinal mode with linewidth less than 40 MHz and sufficient power (∼11 kW) to saturate the far-infrared emission transition at the amplifier input. Pumped by ∼8 J of CO2, the amplifier has produced up to 156 kW of narrow-line 496-μm output. The amplifier gain is found to be sensitively dependent upon the relative timing of the FIR oscillator and CO2 pump pulses.
Surface acoustic wave image scanning using phase modulation
Authors: Scott M. L. , Rahn J. P.
Published: February 2003

Optical image scanning utilizing the phase modulation of a surface acoustic wave in a separated medium configuration of silicon on lithium niobate has been experimentally demonstrated with two similar techniques. In on e technique the long-lived silicon surface states are charged and the image is scanned by a short counterpropagating acoustic pulse. In the second technique the surface states are charged by a short acoustic pulse but the image is scanned by a short pulse of uniform optical illumination.
Mode properties of GaAs-Ga1−xAlxAs heterostructure inverted-ridge optical waveguides
Authors: Tsang Won-Tien , Wang Shyh
Published: February 2003

Clean mode excitation and transmission have been observed in inverted-ridge waveguides fabricated by liquid-phase epitaxy of Ga0.7Al0.3As-GaAs structures over preferentially etched channels.
Critical currents in Nb3Sn fast-neutron irradiated at 6 K
Authors: Colucci S. L. , Weinstock H. , Brown B. S.
Published: February 2003

The short-section critical current density jc of neutron-irradiated Nb3Sn composite wires has been measured at 4.2 K in transverse magnetic fields up to 10 T. Irradiation was conducted at ∼6 K, and jc measurements were made after annealing to 77 K. A fluence of 4.8×1017 n/cm2 (E≳0.1 MeV) increased jc(H) (for H≳1.5 T) above high unirradiated values (about 1×106 A/cm2 at 4 T). The enhancement in jc increased with field, to 45% at 10 T. Samples irradiated to 1.1×1018 n/cm2 showed enhancements in jc a few percent less than samples given the lower dose. After annealing to 295 and 415 K, roughly half of the jc enhancement remained for H≳4 T. Changes in the defect structure caused by irradiation and subsequent annealing, and which are responsible for increased flux pinning, are discussed.
Double heterojunction PbS-PbS1−xSex-PbS laser diodes with cw operation up to 96 K
Authors: Preier H. , Bleicher M. , Riedel W. , Maier H.
Published: February 2003

Double heterojunction PbS-PbS1−xSex-PbS laser diodes have been fabricated by hot-wall molecular beam epitaxy. The lasers had stripe geometry of 100-μm width formed by MgF2 passivation. Structures for electron and hole injection, respectively, are compared. Devices with 1-μm-thick active layers showed threshold current densities of about 400 A/cm2 at 77 K and 1.4×104 A/cm2 at 190 K. cw operation could be realized up to 96 K.
LaF3 infrared detector
Authors: Sher A. , Fales C. L. , Stubblefield J. F.
Published: February 2003

A new class of infrared detectors is proposed and experimental results are presented for a prototype device. The material used is LaF3, an ionic conductor with a capacitance that varies exponentially with temperature. The detectivity of a prototype detector is estimated from measured signal voltages and incident power, and a Johnson noise voltage is calculated from the measured resistance. At a modulation frequency of 20 Hz the estimated detectivity is ∼2×106 cm Hz1/2 W−1. For the parameters characterizing this device, the estimated detectivity is consistent with a theoretical prediction. The theory further predicts an optimum detectivity of ∼109 cm Hz1/2 W−1 for much thinner devices than the prototypes.
Grating-coupled GaAs single heterostructure ring laser
Authors: Scifres D. R. , Burnham R. D. , Streifer W.
Published: February 2003

We report pulsed operation of an electrically pumped GaAs single heterostructure ring laser at 77 °K. Guided modes within the laser are totally internally reflected at cleaved facets and output beams are obtained by coupling from an integrated grating. Thresholds as low as 700 A/cm2 have been obtained and highly polarized highly collimated beams (1°×7° divergence) with a total output power of 70 mW have been observed.
Saturation of the junction voltage in stripe-geometry (AlGa)As double-heterostructure junction lasers
Authors: Paoli Thomas L. , Barnes Peter A.
Published: February 2003

Saturation of the junction voltage has been observed to occur at the onset of lasing in cw stripe-geometry (AlGa)As double-heterostructure junction lasers. Simultaneous measurements of the nonlasing but amplified spontaneous emission confirm that saturation of the optical gain and spontaneous emission accompany the voltage saturation as expected. With well-behaved lasers the observed saturation is maintained over currents to at least 50% above threshold. In other devices, a loss of saturation is commonly observed to occur simultaneously with a nonlinearity in the current dependence of the lasing emission.
Probability of static fatigue failure in optical fibers
Authors: Kalish David , Tariyal B. K.
Published: February 2003

An expression for the probability of static fatigue failure in glass is developed based upon a Weibull-type cumulative strength distribution and a fracture mechanics slow crack growth law. The validity of the analytical model is tested with tensile strength and static fatigue data for fused silica optical fibers. Good agreement between the model and experimental results is demonstrated. Examples for using this model as a predictive tool are presented
Use of thin carbon films for selective chemical etching and epitaxial deposition of III-V semiconductors
Authors: Olsen G. H. , Ban V. S.
Published: February 2003

Very thin (2 to 100 Å) carbon films have been found to be extremely effective as pattern-definition masks for the selective deposition of III-V compounds by vapor-phase epitaxy (VPE) and liquid-phase epitaxy (LPE). High-quality epitaxial layers may subsequently be deposited after removal of the carbon film. This enables complex structures such as optical waveguides to be prepared in these materials.
Optical birefringence of thin GaAs-AlAs multilayer films
Authors: van der Ziel J. P. , Ilegems M. , Mikulyak R. M.
Published: February 2003

The measured birefringence of the refractive indices of GaAs-AlAs multilayers grown by molecular beam epitaxy is found to vary from 0.056 at 0.9 μm to 0.042 at 1.1 μm.
Experimental results with acoustic lenses in a Bragg-diffraction imaging system
Authors: Schlussler L. , Wade G.
Published: February 2003

A cylindrical acoustic lens, inserted into the sound cell of a Bragg-diffraction imaging system, can substantially improve the resolution. In the conventional system, the resolution for an object which spatially modulates the isonifying beam in a direction parallel to the propagation of the laser light is determined by the numerical aperture of the wedge-forming optical lens. However, with the cylindrical acoustic lens in the system, the above resolution is instead determined by the numerical aperture of this acoustic lens. The use of this lens also eliminates the need for several optical components in the system and provides directly for an image with a correct aspect ratio.
Liquid-phase epitaxial growth of Ga1−xAlxAs on the side and top surfaces of air-exposed Ga1−yAlyAs
Authors: Tsukada Toshihisa
Published: February 2003

The LPE growth of Ga1−xAlxAs on the mesa-etched and air-exposed surfaces of Ga1−yAlyAs is described. The LPE is shown to begin and proceed at the intersection of the vertical plane (mesa-etched side) and the horizontal plane (surface of the epitaxial layer). The melt-back process has also been observed to proceed fast at an intersection such as this. The LPE technique combined with the mesa etching is shown to be effective in obtaining the growth on the top surface of Ga1−yAlyAs provided the aluminum fraction y is relatively small (y≲0.2). This process should prove useful in the fabrication of DFB lasers, as well as optical components such as GaAlAs waveguides and couplers.
Experiments on 558-nm argon oxide laser system
Authors: Hughes William M. , Olson N. Thomas , Hunter R.
Published: February 2003

Vacuum ultraviolet (VUV) photolysis of N2O immersed in high-pressure Ar has been used to produce O(1S0) at high density. A two-chamber apparatus was used to prevent the effects of electron and ion collision in the experimental volume, thereby providing a much clearer kinetic situation. The gain profile and stimulated emission cross section near 558 nm and the upper-state lifetime were determined for ArO.
Observation of first Stokes, second Stokes, and anti-Stokes radiation from a mercury cadmium telluride spin-flip Raman laser
Authors: Kruse Paul W.
Published: February 2003

Single-crystal Hg0.77Cd0.23Te has been employed in a spin-flip Raman laser to generate first Stokes and anti-Stokes radiation when pumped at 10.60 μm, and first Stokes, second Stokes, and anti-Stokes radiation when pumped at 10.28 μm.
Cerenkov radiation as a light source for the 2000–620-Å spectral range
Authors: Piestrup M. A. , Powell R. A. , Rothbart G. B. , Chen C. K. , Pantell R. H.
Published: February 2003

Spectral power density from Cerenkov radiation was measured in the vacuum ultraviolet from 2000 to 620 Å. The radiation was produced by passing a 500-MeV 1-mA-peak-current electron beam through 1.4 m of 1 atm of helium gas at room temperature. In the photon energy range from 6 to 20 eV, approximately 1014 photons /sec/Å/mA of electron-beam current were emitted, and our detection apparatus attenuated the radiation by 4–5 orders of magnitude.
X-ray topographic observation of dark-line defects in GaAs-Ga1−xAlxAs double-heterostructure wafers
Authors: Kishino Seigô , Nakashima Hisao , Chinone Naoki , Ito Ryoichi
Published: February 2003

Optically induced dark-line defects (DLD’s) in GaAs-Ga1−xAlxAs double-heterostructure (DH) wafers have been observed by x-ray topography for the first time using the x-ray anomalous transmission effect. This topography, which is sensitive to defects in the thin epitaxial layers, has been successfully applied to the observation. As a result, it has been observed that DLD’s oriented along 〈110〉 directions are composed of dislocations with Burgers vectors of (1/2) a 〈110〉 parallel to the growth surface. It is also shown that the DLD’s originate from both substrate dislocations and crystal edges.
Field-effect modulation of detectivity in PbS photoconductors
Authors: Kramer Gordon , Levine Michael A.
Published: February 2003

Results obtained with lead sulfide photoconductive insulated-gate field-effect transistors (photo-IGFET’s) are presented. Detectivity modulation is provided by the gate electrode. The n-type PbS film was depleted of carriers by applying a negative gate potential, and the detectivity was increased by a factor of 200 while the noise remained constant. Detectivities of 2×1010 cm Hz1/2/W were obtained at 173 °K and 500 Hz for a 180° field of view and a 300 °K background. The devices exhibited stable operating characteristics and showed no significant performance change after 18 months under ambient laboratory conditions. They were fabricated entirely by vacuum deposition in a single pumpdown, and the various conducting, insulating, and semiconducting films were deposited successively through accurately registered metal shadow masks.
Enhancement of emission intensity in indirect-gap AlxGa1−xAs (x=0.53) by nitrogen-ion implantation
Authors: Makita Yunosuke , Gonda Shun-ichi , Ijuin Hachiro , Tsurushima Toshio , Tanoue Hisao , Maekawa Shigeru
Published: February 2003

Nitrogen ions were implanted into indirect-gap AlxGa1−xAs (x=0.53) and photoluminescence measurements were made at 2 °K as a function of annealing temperature. After sufficient annealing three emission bands were observed presumably due to the substitution of the nitrogen atoms with the host As atoms and the integrated intensity of the luminescence of the wafer increased by about 200 times compared with that of the unimplanted and annealed wafer. This can probably be ascribed to the formation of isoelectronic traps in the AlxGa1−xAs : N system.
Experimental evidence of laser-induced separations in bulk gas mixtures
Authors: Rinehart Edgar A. , Richardson Jeffery H. , Johnson David C. , Hrubesh Lawrence W.
Published: February 2003

Radiation from a cw CO2 laser is used to separate SF6 molecules from helium molecules in a bulk mixture of each, by resonant radiation pressure. These experimental results demonstrate that selective absorption of radiation can cause physical separations of molecules within a diffusion-limited geometry.
Optical backward parametric fluorescence in sodium nitrite
Authors: Chemla D. S. , Batifol E.
Published: February 2003

We present the first observation of optical backward-traveling-wave (BTW) parametric fluorescence, in a sodium nitrite crystal pumped by a coumarin dye laser. Several aspects of BTW parametric interactions are discussed. This experiment provides a feasibility test of optical BTW parametric oscillators.
Deep donor state of cobalt in silicon
Authors: Wong David C. , Penchina Claude M.
Published: February 2003

Photoconductivity measurements on p-type and n-type silicon doped with cobalt show that the deep cobalt donor level is fixed in energy 0.384±0.005 eV above the valence band, while the band gap of silicon varies with temperature. This result is consistent with (but much more precise than) measurements of the temperature dependence of resistivity and Hall effect; it contrasts with the behavior of the gold donor level which has been reported to be fixed in energy relative to the conduction band. Combining the present results with previously reported measurements of the thermal rate of hole emission, we obtain the first estimate of the temperature dependence of the cross section for capture of holes by neutral cobalt donors: σp0∼Tm, where m=−2.5±0.4.
New application of Se-Ge glasses to silicon microfabrication technology
Authors: Nagai Haruo , Yoshikawa Akira , Toyoshima Yoshio , Ochi Osamu , Mizushima Yoshihiko
Published: February 2003

A selective etching effect due to photoexposure of Se-Ge glass films was found. The possibilities of applying this phenomenon to the patterning of layers for silicon device processing and for the fabrication of photomasks were investigated. The results showed that the Se-Ge glass has certain advantages in these applications.
Antimony doping of Si layers grown by solid-phase epitaxy
Authors: Lau S. S. , Canali C. , Liau Z. L. , Nakamura K. , Nicolet M.-A. , Mayer J. W. , Blattner Richard J. , Evans C. A.
Published: February 2003

We report here that layers of Si formed by solid-phase epitaxial growth (SPEG) can be doped intentionally. The sample consists initially of an upper layer of amorphous Si (∼1 μm thick), a very thin intermediate layer of Sb (nominally 5 Å), and a thin lower layer of Pd (∼500 Å), all electron-gun deposited on top of a single-crystal substrate (1–10 Ω cm, p type, 〈100〉 orientation). After a heating cycle which induces epitaxial growth, electrically active Sb atoms are incorporated into the SPEG layer, as shown by the following facts: (a) the SPEG layer forms a p-n junction against the p-type substrate, (b) the Hall effect indicates strong n-type conduction of the layer, and (c) Auger electron spectra reveal the presence of Sb in the layer.
Measurement of intense magnetic fields associated with laser−produced plasmas
Authors: Serov R. , Richardson M. C.
Published: February 2003

Measurements have been made with subnanosecond resolution of the azimuthal magnetic field spontaneously associated with plasmas produced by high-intensity (1012–1014 W/cm2) 1-nsec-duration CO2 laser pulses. In addition to a distinct dependence on background argon gas pressure, it is found that the magnetic field displays a 1/r2 radial dependence, and its onset is synchronous with the initial formation of the plasma.
Self-trapping of a laser beam in a cylindrical plasma column
Authors: Feit M. D. , Fleck J. A.
Published: February 2003

The laser heating of an initially uniform plasma column has been modeled in a self-consistent way, including the effects of medium magnetohydrodynamics and refraction and diffraction of the laser light. The results show that a portion of the pulse can become trapped, leading to a pattern of alternate focusing and defocusing of the beam.
cw tunable laser-sideband generation from 5.5 to 6.5 μm by light scattering from spin motion in a spin-flip Raman laser
Authors: Nguyen V. T. , Burkhardt E. G.
Published: February 2003

We have succeeded in generating cw laser sidebands at wavelengths tunable from ∼5.5 to ∼6.5 μm. The behavior of the power output of the generated radiation is described quantitatively by using the equivalence between four-photon mixing and Raman scattering from coherent spin motion in a spin-flip Raman laser.
Optical grating coupling between low-index fibers and high-index film waveguides
Authors: Hammer J. M. , Bartolini R. A. , Miller A. , Neil C. C.
Published: February 2003

Grating couplers between low-refractive-index (n ≈1.5) optical fibers and high-refractive-index (n ≈2.2) electro-optic planar guides have been analyzed and demonstrated. Coupling efficiencies of 6% between single modes of a film and a fiber have been observed. Efficiencies of approximately 86% between single-mode fibers and films using blazed backward-wave gratings are predicted. In addition, low-loss low-optical-aperture multimode fibers may be coupled to single-mode films with efficiencies greater than 50% and angular spreads less than 0.5°.