bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexible infrared-transmissive metal waveguides
Authors: Garmire E. , McMahon T. , Bass M.
Published: February 2003

We report unexpectedly low-loss optical transmission at 10.6 μm through a 1-m-long hollow rectangular metallic waveguide bent through 90° in a 50-cm radius of curvature. This demonstrates that flexible infrared-transmissive (FIT) waveguides can deliver CO2 laser power to targets nearly as conveniently as optical fibers guide visible light.
Temperature effects in Schottky-barrier solar cells
Authors: Bhaumik B. , Sharan R.
Published: February 2003

It has been reported recently that the short-circuit current Isc of silicon Schottky-barrier solar cell increases with increasing operating temperature. The increase in Isc has been attributed to the availability of extra photons, belonging to the long-wavelength range of the solar spectrum, due to the lowering of the forbidden energy gap of silicon with increasing temperature. The purpose of the present letter is to show that the contribution to the increase of Isc due to the mechanism mentioned above is negligible and cannot explain the experimental results. Instead, it has been found that good agreement with experimental results is obtained when the increase in Isc with increasing temperature is calculated by taking the change of the absorption coefficient of the semiconductor with temperature at all wavelengths.
MOS measurement of oxygen recoils from As implantation into silicon dioxide
Authors: Goetzberger A. , Bartelink D. J. , McVittie J. P. , Gibbons J. F.
Published: February 2003

The depth distribution of oxygen recoils from As implantation was studied by employing MOS surface state techniques. Arsenic was implanted into an SiO2 film on Si such that the recoil oxygen reached the silicon interface. By varying oxide thickness, the depth distribution could be determined. The distribution at greater depth is exponential with a characteristic length of 220 Å for an As implant at 100 keV.
New piezoelectric crystal: Synthetic fresnoite (Ba2Si2TiO8)
Authors: Kimura Masakazu , Fujino Yoshio , Kawamura Tsutomu
Published: February 2003

A fresnoite (Ba2Si2TiO8) single crystal was grown from the melt by the Czochralski method. Synthetic fresnoite has an electromechanical coupling factor in the thickness shear mode of k15=0.28, and a resonance-frequency temperature coefficient in this mode of Tfr=−33 ppm/°C. Fresnoite is considered to be superior to Ba2Ge2TiO8 for various piezoelectric applications because of the absence of microtwins observed in Ba2Ge2TiO8.
Ablation-driven targets for electron-beam fusion: Density problem with very low-Z ablators
Authors: Sweeney M. A.
Published: February 2003

The behavior of DT-filled implosion targets with very low-Z (carbon) ablators irradiated by 1-MeV electrons is compared to that with intermediate- and high-Z ablators. The inner part of the pusher is of lower entropy due to decreased bremsstrahlung heating. The DT is shielded from compression until later in the energy pulse, when it is more strongly compressed. However, thicker ablators transfer less energy to the pusher; hence, diamond-carbon ablators perform better than graphite-carbon. Precompression of graphite-carbon with a laser does not reduce the minimum power required for break-even, but does lead to increased gain above break-even.
Pressure dependence of the electron density in electron-beam-excited rare-gas plasmas
Authors: Werner C. W. , Zamir E. , George E. V.
Published: February 2003

The peak electron density in e-beam-excited rare-gas plasmas has been studied as a function of pressure, using inverse bremsstrahlung absorption techniques. It was found that the heavier rare gases exhibit broad maxima beyond which the peak electron density decreases monotonically with pressure. No maxima were observed in helium or neon over the pressure range investigated (0–400 psia). Data are presented along with a proposed theoretical explanation for the observed phenomena.
Image transfer through a curved light-focusing plastic rod
Authors: Ohtsuka Yasuji , Senga Takao , Sugano Toshiko
Published: February 2003

The imaging characteristic of a curved (curvature ρ) light-focusing plastic rod (LFR), with a constant quadratic gradient of refractive index and radius rp is examined. It was found that curving a LFR produces limitation in the image field, and that the extent of the limiation is inversely proportional to arpρ according to a relation derived theoretically. In the case of a partially curved LFR, the image location was found to shift periodically with increase in the curved portion.
Direct optically pumped multiwavelength CO2 laser
Authors: Buchwald M. I. , Jones C. R. , Fetterman H. R. , Schlossberg H. R.
Published: February 2003

An HF laser was used to directly pump various isotopic forms of CO2. Intense laser emission was observed on numerous lines in the 4.3-, 10.6-, and 17-μm regions. All observed 4.3- and 17-μm CO2 laser emission lines were assigned. The pressure dependence of lasing spectra and laser pulse temporal features were examined.
Distributed feedback Pb1−xSnxTe double-heterostructure lasers
Authors: Walpole J. N. , Calawa A. R. , Chinn S. R. , Groves S. H. , Harman T. C.
Published: February 2003

Distributed feedback laser operation is demonstrated in stripe-geometry Pb1−xSnxTe double heterostructures grown by molecular-beam epitaxy. The grating of 1.1 μm periodicity operates in first order near 745 cm−1 (13.4 μm) under pulsed conditions in a limited range of heat-sink temperatuers (∼30–65 K) where both gain and the Bragg reflection condition can be achieved. The guide index ng≃6.1 is consistent with theoretical estimates. In Pb1−xSnxTe DH devices, by corrugating the surface after all epitaxy is completed, a large coupling coefficient for Bragg reflection can be achieved because the last confining layer can be made very thin and the grating aspect ratio large.
Stimulated and laser emission involving nitrogen isoelectronic impurities in AlxGa1−xAs (x=0.39, 77 °K)
Authors: Makita Yunosuke , Gonda Shun-ichi , Ijuin Hachiro
Published: February 2003

By optical pumping, laser emission was achieved at 77 °K involving those nitrogen atoms in direct-gap AlxGa1−xAs (x=0.39), which were incorporated by ion implantation. The energy of laser emission of nitrogen-implanted material was about 14.4 meV lower than that of nitrogen-free material.
ESR detection of antisite lattice defects in GaP, CdSiP2, and ZnGeP2
Authors: Kaufmann U. , Schneider J. , Räuber A.
Published: February 2003

The occurrence of phosphorus antisite defect centers on cation sites in GaP, CdSiP2, and ZnGeP2 has been demonstrated by electron spin resonance. The paramagnetic defect is identified by its characteristic hyperfine and ligand hyperfine interaction, representative for a 31P31P4 cluster. The possible role of the antisite lattice defect as a center of nonradiative recombination in LEC-grown GaP is emphasized.
Ejection of material from shocked surfaces
Authors: Asay J. R. , Mix L. P. , Perry F. C.
Published: February 2003

Velocity interferometry and double-pulse holography have been used to study material ejected from surfaces which are impulsively loaded with plane shock waves. Experiments performed on aluminum shocked to 25 GPa (250 kbar) provide the average mass and velocity distribution as well as the spatial distribution of material ejected from the surface. A total mass of about 3 μg/cm2 was ejected when the shock arrived at the surface in the present experiments, and a substantial part of this material resulted from jetting at small pits on the surface.
Distributed feedback buried heterostructure diode laser
Authors: Burnham R. D. , Scifres D. R. , Streifer W.
Published: February 2003

We report room-temperature operation of a buried heterostructure distributed feedback diode laser. The device operates in a single TE polarized longitudinal mode over a temperature range from 232 to 324 K and exhibits a temperature sensitivity of 0.72 Å/K. In comparison, the variation for a similar Fabry-Perot diode is 3.4 Å/K.
Observation of stimulated emission in KrCl
Authors: Eden J. Gary , Searles Stuart K.
Published: February 2003

Stimulated emission at 222.9±0.1 nm in KrCl has been observed in electron-beam-excited Ar/Kr/Cl2 mixtures. Approximately 50 kW of laser output in a 30-ns pulse with ∼14% output coupling has been obtained. Both the peak spontaneous emission wavelength and vibrational spacing (ωe) of KrCl* are in agreement with the alkali-halide analog (RbCl) model. The kinetics of this new rare-gas–halide laser molecule are briefly discussed.
Formation and quenching of XeF and KrF electronic excited states
Authors: Eden J. Gary , Searles Stuart K.
Published: February 2003

Electron collisional quenching of the KrF* and XeF* electronically excited state populations in e-beam-excited plasmas has been observed. Also, significant enhancement of both XeF* and KrF* fluorescence was obtained in low-pressure (p<225 Torr) Xe (or Kr)/F2 mixtures with the addition of 12.5–200 Torr helium. Spectral measurements show that this enhancement is not due to helium collisional relaxation of the exciplex vibrational manifold. These effects prohibit a straightforward estimate of the XeF* or KrF* spontaneous radiative lifetimes.
Low-threshold room-temperature embedded heterostructure lasers
Authors: Lee C. P. , Samid I. , Gover A. , Yariv A.
Published: February 2003

Room-temperature embedded double-heterostructure injection lasers have been fabricated using selective liquid phase epitaxial growth. Threshold current densities as low as 1.5 kA/cm2 have been achieved in lasers grown through stripe windows opened in epitaxial GaAlAs masks.
Behavior of low-impedance relativistic electron diodes in converging magnetic gradients
Authors: Phelps D. A. , Oldenettel J. R. , Korn P. , Shannon J.
Published: February 2003

The behavior of a large-area field emission diode located in a 4:1 converging magnetic gradient is described. Evidence is presented that this technique significantly reduces the early-time L/R decay into the nominal 3/4 Ω space-charge-limited impedance characteristic. The elimination of late-time plasma closure in the diode gap is also demonstrated. Due to these characteristics, a significant reduction in the time-averaged diode impedance and an improvement in the pulse-line–diode energy transfer efficiency has been obtained—thereby permitting first observations of efficient matching to a sub-ohm pulsed electron accelerator.
Photoelectrolysis of water with TiO2-covered solar-cell electrodes
Authors: Morisaki H. , Watanabe T. , Iwase M. , Yazawa K.
Published: February 2003

A TiO2–solar-cell hybrid structure has been used successfully as the anode electrode in the photoelectrolysis of water. The TiO2 films have been fabricated by chemical vapor deposition. Conversion efficiency of solar energy of about 0.1% has been attained in the preliminary experiment.
Interferometric real-time display of cw dye laser wavelength with sub-Doppler accuracy
Authors: Hall J. L. , Lee S. A.
Published: February 2003

We describe an automatic fringe-counting interferometer with real-time wavelength readout for cw laser sources. Sub-Doppler absolute wavelength accuracy (∼2×10−7) is demonstrated with saturated absorption spectroscopy in neon.
Improved light-output linearity in stripe-geometry double-heterostructure (Al,Ga)As lasers
Authors: Dixon R. W. , Nash F. R. , Hartman R. L. , Hepplewhite R. T.
Published: February 2003

Nonlinearities in the optical-power-output–versus–current characteristics of (Al,Ga)As stripe-geometry double-heterostructure lasers are found to be associated with excessive spectral broadening, asymmetries in the outputs from the two mirrors, and spatial movements of the lasing mode within the width of the stripe. Manifestations of these nonlinearities are severely deleterious in a variety of optical fiber communication applications. It is shown that the impact of these defects may be significantly reduced, with little lasing-threshold-current penalty, by fabricating devices with narrower stripe widths.
Oxide thickness dependence of high-energy-electron-, VUV-, and corona-induced charge in MOS capacitors
Authors: Hughes G. W. , Powell R. J. , Woods M. H.
Published: February 2003

The radiation-induced flatband voltage shift of MOS capacitors using dry-O2-grown SiO2 is shown to vary as the square of oxide thickness for penetrating 1-MeV electron radiation and linearly with oxide thickness for nonpenetrating 10.2-eV photon radiation. Corona discharge experiments on unmetallized portions of the same oxidized silicon wafers also show a flatband voltage shift linearly dependent upon oxide thickness. These experiments provide strong evidence to support a simple generation, transport, and trapping model for radiation charging of SiO2. The results also show that for dry oxides the density of trapped holes near the Si-SiO2 interface is indepenent of oxidation time.
Temperature dependence of superconducting critical current density and upper critical field for the V/Hf0.4Zr0.6 Laves phase tape
Authors: Inoue K. , Tachikawa K.
Published: February 2003

The temperature dependence of the superconducting critical current density Jc and the upper critical field Hc2 has been studied for the composite-processed V/Hf0.4Zr0.6 tape, in which the C-15 crystal-type Laves phase compound is formed by diffusion between the vanadium sheath and the Hf0.4Zr0.6 alloy core. Jc of the V/Hf0.4Zr0.6 rapidly increases with decreasing temperature. At 1.7 K the V/Hf0.4Zr0.6 shows higher Hc2 and Jc than those of commercially available Nb3Sn and V3Ga. A superconducting magnet wound with V/Hf0.4Zr0.6 tape might be able to generate a magnetic field exceeding 200 kOe at 1.7 K.
19F range-energy curve in Si from 100 to 550 keV
Authors: Dietrich H. B. , Plew L. E.
Published: February 2003

The range statistics for C, F, Ne, Al, and Si in Si recently published by Gibbons, Johnson, and Mylroie (GJM) are significantly different from the predictions of the LSS theory. This difference exists because in their calculation GJM made use of measured electronic stopping powers (Se) for channeled ions. The scaling procedure employed by GJM builds into their calculation the pronounced Z1 oscillations observed in the Se of channeled ions. Use of the measured electronic stopping powers was limited to N, O, P, Cl, Ar, and the above mentioned ions in Si. In order to make an experimental check of the scaling procedure employed the range-energy curve for 19F in Si has been measured between 100 and 550 keV. The following observations can be made: (1) The experimental range-energy curve for 19F is in good agreement with LSS calculations and (2) the measured ranges are significantly less than the predictions of Gibbons, Johnson, and Mylroie. These results are interpreted as strong evidence against the validity of scaling Eisen’s measurements of the electronic stopping power for channeled ions over to random trajectories.
Measurements of surface fluctuations of a glass slide with a laser pulse
Authors: Ho W. C. , Leung A. F.
Published: February 2003

Laser-induced damage of a thin metal film coated on one side of a microscope slide can be used to determine the surface properties of the slide. In addition, the surface characteristics of an optically flat quartz disk have been analyzed.
The role of oxygen in irradiated arsenic-doped silicon
Authors: Evwaraye A. O.
Published: February 2003

Majority carrier traps produced in arsenic-doped silicon by 1.5-MeV electron irradiation are characterized by deep level transient spectroscopy. Four traps are observed including a new defect located at Ec−0.30 eV. It is also observed that oxygen plays a vital role in the annealing mechanism of the arsenic-vacancy pair. This defect, with a level at Ec−0.42 eV, has two annealing stages, the first being much faster than the second. Its first annealing stage cannot be explained by another defect superimposed upon the As-V pair.
Directional coupler for multimode optical fibers
Authors: Jeunhomme L. , Pocholle J. P.
Published: February 2003

A simple directional coupler using induced mode conversion has been built. The fraction of energy extracted from the fiber can easily be varied from −10 to −3 dB with an insertion loss close to the theoretical limit. This coupler can also be removed from the fiber if the derivation is no longer desired and appears then as a versatile clip-on coupler for temporary extraction of the light travelling in the fiber.
VUV fluorescence of Nd3+-, Er3+, and Tm3+-doped trifluorides and tunable coherent sources from 1650 to 2600 Å
Authors: Yang K. H. , DeLuca J. A.
Published: February 2003

Broad-band vacuum ultraviolet (VUV) fluorescence has been observed in Nd3+-, Er3+-, and Tm3+-doped LaF3, YF3, LiYF4, and LuF3 by electron-beam and VUV excitation. The VUV excitation spectra indicate a large Stokes shift (≳5000 cm−1) and a high fluorescence quantum yield of 0.8. The threshold power for laser action in these crystals by optical pumping has been estimated. Using a molecular H2 laser as a pumping source, a laser system which is tunable from 1650 to 2600 Å could be constructed.
Frequency multiplexing light source with monolithically integrated distributed-feedback diode lasers
Authors: Aiki K. , Nakamura M. , Umeda J.
Published: February 2003

A frequency multiplexing light source is realized by monolithically integrating GaAs-GaAlAs distributed-feedback diode lasers with different grating periods and passive waveguides on a GaAs substrate. The lasers with wavelength separation of ∼20 Å are modulated independently, and the output beams are obtained from a common launching waveguide.
Passive mode locking and picosecond pulse generation in Nd:lanthanum beryllate
Authors: Goldberg L. S. , Bradford J. N.
Published: February 2003

The passive mode-locking characteristics of Nd:lanthanum beryllate (Nd:BEL) have been studied for the two linearly polarized laser transitions at 1.070 and 1.079 μm. Streak-camera measurements of pulse duration and spectral broadening in the pulse-train emission show that Nd:BEL can generate minimum-bandwidth pulses of ⩽15 psec, some 2–3 times shorter than for Nd:YAG.
Energy dependence of amorphizing implant dose in silicon
Authors: Dennis John R. , Hale Edward B.
Published: February 2003

The radiation-induced transformation from crystalline to amorphous silicon was studied using ion implantation. The ion energy was varied from 20 to 180 keV for Li+, N+, Ne+, Ar+, and Kr+. The energy dependence of the critical amorphizing dose was determined by electron spin resonance. Comparison of the data with theoretical calculations of the energy density deposited into atomic processes showed good agreement. This energy-dependent agreement gave evidence that energy density is important to the transformation at both low and high implantation temperatures.
Phase tuning in optical directional coupler
Authors: Mikami Osamu , Noda Juichi
Published: February 2003

A new phase-tuning method for an optical directional coupler fabricated in a c-plate LiNbO3 by TiO2 diffusion is presented. The method consists of applying a bias voltage to an additional electrode set closely outside the modulation electrodes. The propagation constants of the two waveguides could be made equal by a bias voltage of 5 V. The modulation voltage of 8 V was unaffected by the bias voltage.
Light-focusing plastic rod prepared by photocopolymerization of methacrylic esters with vinyl benzoates
Authors: Ohtsuka Yasuji , Nakamoto Ichiro
Published: February 2003

A new preparation method of a light-focusing plastic rod (LFR) is reported, where the photocopolymerization of methacrylic esters (M1) such as methyl methacrylate (MMA) with vinyl benzoates (M2) such as vinyl benzoate (VB), vinyl o-chlorobenzoate, and vinyl o,p-dichloro-benzoate was carried out. The M1-M2 mixture placed in a glass tube was exposed to uv light by rotating a glass tube about its axis. LFR prepared from a MMA-VB pair has a quadratic gradient constant with a refractive index A= (3∼11) ×10−3 mm−2, an internal loss of light transmission IL= (3∼12) dB/m, and a ratio of the radius of the imaging region to the rod radius (ri/rp) =0.5∼0.7.
Electric-discharge-pumped nitrogen ion laser
Authors: Laudenslager James B. , Pacala Thomas J. , Wittig Curt
Published: February 2003

A preionized transverse electric-discharge-pumped N+2 charge-transfer laser oscillating on the (B2Σ+u−X2Σ+g) transition of N+2 is reported. Peak power of 180 kW in a 8-nsec FWHM laser pulse has been obtained with a 0.1% mixture of N2 in helium at a total pressure of 3 atm. The most intense laser oscillation occurs on the (0,1) vibrational transition at 427.8 nm.
Precipitation of oxygen in silicon
Authors: Freeland P. E. , Jackson K. A. , Lowe C. W. , Patel J. R.
Published: February 2003

At high temperatures (1200 °C) the precipitation of oxygen in bulk dislocation-free Czochralski silicon is inhibited by the absence of nucleation centers. A substantial supersaturation corresponding to a temperature drop of about 80 °C below the equilibrium saturation temperature is necessary for nucleation to occur. However, following a preliminary low-temperature treatment (700 °C) precipitation occurs at a substantially smaller undercooling. This suggests that precipitation in crystals without a prior low-temperature treatment occurs by homogeneous nucleation in the crystalline phase, in the absence of structural defects. Using classical nucleation theory the surface free energy of the precipitate is calculated to be about 100 erg/cm2 and the critical nucleus contains about 200 oxygen atoms.
Optical rectification due to free carriers in gallium phosphide
Authors: Gibson A. F. , Kimmitt M. F. , Kothari S. , Hatch C. B. , Serafetinides A.
Published: February 2003

A strong optical rectification effect is observed in n-type GaP, peaking near the wavelength range covered by HF lasers. The optical rectification is ascribed to free electrons and is interpreted in terms of the band structure proposed by Lawaetz. The effect can be exploited in the fabrication of fast robust room-temperature radiation detectors in a wavelength range in which germanium photon drag detectors are not applicable.
Laser light-scattering technique for measurements of turbulent mixing
Authors: Shaughnessy E. J. , Morton J. B.
Published: February 2003

A laser light-scattering technique for measuring the relative particle concentration in a turbulent mixing field is described. The effects of ambiguity noise and optical path attenuation noise on the measurement of concentration fluctuations with this technique are discussed. Measurements of the admixture spectra in a turbulent jet show good agreement with those obtained using hot wires.
Multifunction integrated optic device using magnetically alterable phase grating
Authors: Sauter G. F. , Hanson M. M. , Fleming D. L.
Published: February 2003

A magnetically alterable phase grating integrated optic coupler-modulator was formed utilizing the magnetic stripe domains in a LPE film of BixYb3−xFe5O12. Light was coupled to a glass waveguide and 72% intensity modulation was achieved.
Frequency domain measurements of dispersion in multimode optical fibers
Authors: Cohen L. G. , Astle H. W. , Kaminow I. P.
Published: February 2003

A newly developed technique for directly measuring fiber dispersion in the frequency domain as a function of wavelength is described. A number of germanium- and boron-doped fibers have been examined. The least dispersive borosilicate graded-index fiber has a 1-dB bandwidth of 1 GHz, after 1.07 km of propagation at λ=908 nm. Frequency domain measurements were inverted into the time domain after assuming that the phase of a power transfer function could be calculated from its amplitude spectrum.
Proposed picosecond excited-state measurement method using a tunable-laser-induced grating
Authors: Siegman A. E.
Published: February 2003

This letter analyzes a suggested technique for studying excited atomic or molecular states on a picosecond to subpicosecond time scale by using tunable laser beams, without requiring ultrafast laser pulses or optical detectors. In the proposed technique the frequency transform of the impulse response of an excited state is determined by measuring the diffraction of a cw probe laser beam from a moving excited-state grating induced by two intersecting tunable excitation beams, as the frequency difference between the two cw excitation beams is varied.
cw operation of distributed feedback Pb1−xSnxTe lasers
Authors: Walpole J. N. , Calawa A. R. , Chinn S. R. , Groves S. H. , Harman T. C.
Published: February 2003

Distributed feedback Pb1−xSnxTe double-heterostructure lasers grown by molecular-beam epitaxy with cw operation up to 50 K are reported. The grating of 1.1-μm periodicity operates in the first Bragg order near 800 cm−1 (12.5 μm). Single-mode operation is obtained over a wide range of diode current and heat-sink temperature. Continuous current tuning of mode frequency up to 7 cm−1 is obtained, and by varying both diode current and heat-sink temperature complete coverage of the range 795–806.5 cm−1 is demonstrated.
Nonradiative dark regions along surface ripples in GaP LPE layers
Authors: Kajimura Takashi , Aiki Kunio , Umeda Jun-ichi
Published: February 2003

A nonradiative dark region along a surface ripple is observed in optically and electrically excited GaP LPE layers. The region originates from the substrate interface and terminates at the ridge of the surface ripple. It is clearly distinguishable from the known one caused by dislocation in its features. The p-n junction breakdown voltage in this region is lower than that in the radiative region in a LPE layer. This fact suggests that in liquid-phase epitaxy an impurity concentrated region is formed in the growing process of surface ripples. The existence of the region contributes to the deterioration of the characteristics of devices using thin LPE layers.
Preferential doping of rhodamine 6G in a polyurethane optical solid circuit
Authors: Matsuda A. , Iizima S.
Published: February 2003

Introduction of a dye doped region into a passive waveguide area has been established by thermal doping of organic dye in a polymer optical solid-state circuit. Using periodical corrugations with a period of 2050 Å formed on a glass substrate, a N2 laser pumped dye laser—waveguide system has been constructed.
A new optoacoustic cell with improved performance
Authors: Patel C. K. N. , Kerl R. J.
Published: February 2003

We report a novel optoacoustic (OA) cell construction which has improved small absorption measurement capability from 10−9 cm−1 to 10−10 cm−1. The new OA cell is ideally suitable for use with planar output lasers, e.g., diode lasers. Now optoacoustic spectroscopy can be extended to include the effects of low temperatures, electric fields, and magnetic field effects.
Tunable uv generation in KB5O8⋅4H2O to 1966 Å
Authors: Kato K.
Published: February 2003

Efficient generation of tunable uv radiation to 1966 Å has been achieved by type-1 frequency mixing of the outputs of the fourth harmonic of a Nd : YAG laser and a near-infrared dye laser pumped by the second harmonic of the same Nd : YAG laser. A peak power as high as 40 kW with an average power of 2 mW was obtained at 1966 Å.
Depth profile detection limit of 3×1015 atom cm−3 for As in Si using Cs+ bombardment negative secondary ion mass spectrometry
Authors: Williams Peter , Evans Charles A.
Published: February 2003

Depth profiles of As-implanted silicon samples have been determined by secondary ion mass spectrometry in order to establish a practical detection limit for As in Si. By monitoring the AsSi− species, produced in high yield by Cs+ ion bombardment, it is shown that As is detectable down to a background count limit of ∼3×1015 atom cm−3 (50 ppb) during a depth profile of a 250-μm square area.
Elimination of Li2O out-diffusion waveguide in LiNbO3 and LiTaO3
Authors: Chen Bor-Uei , Pastor Antonio C.
Published: February 2003

A novel technique was developed to eliminate the Li2O out-diffusion waveguide in LiNbO3 and LiTaO3 incurred during the process of Ti in-diffusion. The out-diffusion waveguide can be suppressed by annealing the crystals in LiNbO3 powder at 900 °C in a flowing oxygen environment for 1 h or longer.
Peaked Schottky-barrier solar cells by Al-Si metallurgical reactions
Authors: Card H. C. , Yang E. S. , Panayotatos P.
Published: February 2003

The dark currents in Al-nSi Schottky-barrier solar cells are appreciably reduced by low-temperature heat treatments (T<577 °C) which induce metallurgical reactions between the Al and Si. Open-circuit voltages of these cells can be increased by more than 0.2 V as a result of this mechanism.
Magnetostatic surface wave reflectivity of a shallow groove on a YIG film
Authors: Parekh J. P. , Tuan H. S.
Published: February 2003

A field theory for the magnetostatic surface wave (MSSW) reflectivity of a single shallow groove etched on top of an epitaxial YIG film is presented. Computed reflection characteristics are obtained for the case in which the surface of the YIG film is metallized after the groove is etched. It is found that the MSSW reflectivity of a groove is significantly larger than the SAW reflectivity of an equivalent groove on a LiNbO3 substrate.
Singular instabilities on LPE GaAs, CVD Si, and MBE InP growth surfaces
Authors: Rode D. L. , Wagner W. R. , Schumaker N. E.
Published: February 2003

Singular instabilities at crystal growth interfaces of group-IV and III-V semiconductors lead to as-grown surfaces optical devices, however, requirethe achievement of smoth planar layers. We consider the stability of surfaces with respect to singular instabilities and show that stable planar growth interfaces occur at slight deviati8ons from the singular orientation where monatomic growth steps are uniformly arrayed to minimize the interfacial energy resulting from step-step attractive interactions. These results are applied to the elimination of crystal growth terraces in LPE AlGaAs-GaAs laser material. Similar considerations appear to explain pyramid formations on CVD Si and on MBE InP.
Simultaneous holographic and photocurrent studies of the photorefractive effect in LiTaO3 and LiNbO3
Authors: Spinhirne J. M. , Ang D. , Joiner C. S. , Estle T. L.
Published: February 2003

In reduced LiNbO3 : Mn both the photorefractive sensitivity and the simultaneously measured photocurrent result from drift with a polarization-dependent effective ’’internal field’’ of about 6 kV/cm. In reduced undoped LiTaO3 the observed difference in applied fields of the minimum photorefractive sensitivity and zero photocurrent imply charge transport is by a mechanism that cannot be completely described by diffusion and drift in an electric field. The direct measurement of the harmonic content of phase gratings written in several LiNbO3 and LiTaO3 crystals shows termination of charge-transport results from the space-charge field of the hologram.
Dissociative attachment of electrons to F2
Authors: Chen Hao-Lin , Center R. E. , Trainor Daniel W. , Fyfe W. I.
Published: February 2003

By measuring the equilibrated sustainer current density in F2/N2 mixtures under controlled discharge conditions, we have determined the F2 dissociative attachment rate constant at various E/P conditions. The F2+e→F∓F rate constant at an average electron energy of 1.0 eV was found to be 2.3±0.3×10−9 cm3/molecule/sec and increased with decreasing electron energy.
The charge-flow transistor: A new MOS device
Authors: Senturia S. D. , Sechen C. M. , Wishneusky J. A.
Published: February 2003

A new device, the charge-flow transistor (CFT), has been developed to achieve integrated MOS compatibility in sensor applications, such as gas, humidity, and fire detection, where one is interested in monitoring the transverse resistance of a thin film. The resistive material is incorporated into the gate structure of the CFT in such a way that there is a time delay between the application of the gate-to-source voltage and the appearance of a complete channel. This time delay depends on the resistivity of the thin film. A theory of device operation is presented, together with experimental results on the first CFT’s. These results confirm the principles of operation, and demonstrate the utility of the CFT for making fully integrated sensing devices.
GaAs lasers with consistently low degradation rates at room temperature
Authors: Goodwin A. R. , Peters J. R. , Pion M. , Bourne W. O.
Published: February 2003

Simple oxide-insulated stripe-geometry double-heterostructure lasers have been made and life tested as part of an extensive laser reliability program. Early lasers have now been on test for more than 13 000 h and the first batch test has exceeded 7000 h. All the batch test lasers show slow degradation and at least 85% have rates of increase of threshold below 3.3% per 1000 h. Simple visual prebonding selection was used to eliminate defective lasers, and these results demonstrate that within this limitation lives in excess of 7000 h can be consistently achieved.
Wide-band electro-optical tuning of semiconductor lasers
Authors: Tang C. L. , Kreismanis V. G. , Ballantyne J. M.
Published: February 2003

A semiconductor laser having a narrow emission bandwidth (<1 Å) with center wavelength electronically tunable over a large spectral range is demonstrated for the first time. This electro-optically tunable infrared semiconductor laser source should have interesting applications in, for example, optical communications systems, optical radar, and spectroscopy.
Observation of surface flaws in fused silica optical fibers
Authors: Takayama Koichi , Susa Nobuhiko , Hirai Masataka , Uchida Naoya
Published: February 2003

Surface flaws existing in optical fibers are directly observed using an optical microscope and SEM. Among scattering centers observed by launching a He-Ne laser beam into a fiber, those still remaining after careful cleaning of the fiber surface are found to be most probably the flaws. Several cracks and voidlike defects observed by SEM correspond to the scattering centers. Tensile tests have been accomplished for fiber specimens containing the centers. It is found that fractures occur just at the centers in high probability and that fracture strength for the specimens is one-third to two-thirds of the strength for a specimen without an observable scattering center.
Initial degradation mode of long-life (GaAl)As-GaAs lasers
Authors: Hwang C. J.
Published: February 2003

A rapid degradation mode is observed for most of our long-life lasers (⩾5000 h) within the first 100 h of cw operation at room temperature. This degradation saturates thereafter and can be recovered by annealing at temperatures below 150 °C. It is shown that the reduction of gain as a result of decrease in recombination efficiency is the cause for the degradation. Addition of Al(⩾6%) in the active region is found to eliminate the degradation.
Electron-beam-controlled discharge excitation of a CO-C2H2 energy transfer laser
Authors: Nelson L. Y. , Fisher C. H. , Hoverson S. J. , Byron S. R. , O’Neill F. , Whitney W. T.
Published: February 2003

Laser emission in the 8-μm ν2-ν5 band of C2H2 has been observed in electron-beam-controlled discharges in CO-C2H2 mixtures. Line tunability within the P and Q branches has been demonstrated using a grating-controlled cavity. Spectroscopic measurements of the free-running C2H2 laser emission at pressures up to 4 atm indicate significant pressure-broadened line overlap of the closely spaced (<0.2 cm−1) Q-branch lines.
Pulsed H2-F2 laser flame-out
Authors: Woodroffe J. A. , Limpaecher R.
Published: February 2003

Flame-out has been achieved under conditions representative of an atmospheric-pressure repetitively pulsed H2-F2 laser by briefly interrupting the flow of H2 between pulses using a fluidic bistable amplifier.
Electrode- and preionizer-geometry effects on TEA laser discharge formation
Authors: Denes L. J. , Kline Laurence E.
Published: February 2003

We show that both the shape of the electrodes and the spatial distribution of the preionization can play an important role in defining the cross-sectional shape of uv-preionized self-sustained glow discharges in CO2 laser mixtures. Studies of a homogeneous 10×10×100 cm3 discharge are described.
Mixing of N2 laser and dye laser pulses in ADP to generate difference frequency tunable from 0.68 to 1.1 μm
Authors: Sam C. L. , Choy M. M.
Published: February 2003

This paper reports the first direct application of a nitrogen laser as a frequency mixing component in a parametric experiment. Tunable infrared radiation from 0.68 to 1.1 μm is generated by mixing N2 laser and dye laser pulses in ADP. The experimental tuning curve is in good agreement with theory. A peak signal power of 1 W is obtained over an interaction length of 1.1 cm with 7 kW of N2 laser and 5 kW of dye laser power. The signal bandwidth is consistent with those of the input beams. Possible extensions of the tuning range are discussed.
Feedback stabilization of optically levitated particles
Authors: Ashkin A. , Dziedzic J. M.
Published: February 2003

We demonstrate the locking of an optically levitated sphere to an external reference using an electronic feedback system. This provides a new external source of damping for the stabilization and manipulation of particles in vacuum and at atmospheric pressure. The method permits accurate and continuous monitoring of applied forces. Numerous applications are suggested.
High optical power capabilities of Ti-diffused LiTaO3 waveguide modulator structures
Authors: Tangonan G. L. , Barnoski M. K. , Lotspeich J. F. , Lee A.
Published: February 2003

Studies of high optical power density propagation in Ti-diffused LiTaO3 waveguides are described. Optical damage at room temperature involving ’’blow-out’’ of the central output spot into the m line and clean-up phenomena have been observed. Studies at elevated temperature (≈150 °C) indicate that self-annealing of the damage allows these structures to sustain optical power densities up to 11 kW/cm2 at 5145 Å without damage and power saturation. Use of high-purity LiTaO3 is required if room-temperature operation at these high optical power densities is to be achieved.
A superconducting strain transducer
Authors: Adami L. , Cerdonio M. , Ricci F. F. , Romani G. L.
Published: February 2003

We have developed a prototype of a novel strain transducer. The change in magnetic reluctance in a ferromagnetic thorus with a gap due to the applied strain is detected by a superconducting magnetometer (SQUID). Strains as small as Δl/l=10−10 have been detected on a bandwidth of 1 Hz up to 16.7 kHz in a reduced sensitivity version of the apparatus. Further experimentation at higher sensitivity with the present experimental setup is prevented by the background mechanical noise of the building.
Evidence for low surface recombination velocity on n-type InP
Authors: Casey H. C. , Buehler E.
Published: February 2003

A comparison was made of the photoluminescent (PL) intensities of n-type InP and GaAs at room temperature. The PL intensity for InP was over 100 times greater than for comparably doped GaAs. The effect of surface recombination velocity S on the PL intensity was evaluated numerically. When this evaluation is applied to the PL intensity ratios of n-type InP and GaAs it shows that S for n-type InP is sufficiently small to eliminate significant influence of nonradiative surface recombination on the observed PL intensity.
A demonstration of one-atom detection
Authors: Hurst G. S. , Nayfeh M. H. , Young J. P.
Published: February 2003

Resonance ionization spectroscopy, a photoionization method in which all of a given quantum selected species are converted to ion pairs, has been used to develop a detector for a single atom. We have demonstrated the detection of one atom by using a pulsed dye laser to photoionize Cs to saturation and a proportional counter for the detection of single electrons. Some current applications, e.g., the slow transport and chemical reactions of atoms, are briefly discussed. Future applications may include the detection of rare events such as quarks, solar neutrinos, and superheavy elements.
Formation of integrated optics components by multiphoton photorefractive processes
Authors: Verber C. M. , Hartman N. F. , Glass A. M.
Published: February 2003

Phase holograms have been formed in pure outdiffused LiNbO3 waveguides using the photorefractive effect initiated by two-photon absorption. Efficient holograms were recorded with two guided waves, of less than 100 W peak power, and less than 10 μJ optical energy. This technique automatically compensates for wave front perturbations in the guide and allows the formation of various integrated components such as wavelength multiplexers and optical switches.
A bistable Fabry-Perot resonator
Authors: Smith P. W. , Turner E. H.
Published: February 2003

We propose and demonstrate the operation of a novel bistable optical device that exhibits differential gain and can function as an optical switch, limiter, or optical memory element.
Surface stress and the equilibrium shape of an elastic crystal
Authors: Dunham R. S. , Gurtin M. E.
Published: February 2003

We consider the deformation, due to surface stress, of an elastic crystal in the shape of a square. We reduce the problem to one of linear elasticity and obtain a solution using the finite-element method.
Detection of 10-μ radiation with point-contact Schottky diodes
Authors: Tsang Dah-wen , Schwarz S. E.
Published: February 2003

Point-contact Schottky diodes have been used to detect 10.6-μ radiation. Best results were obtained with n-Ge/W contacts. These gave voltage responsivity about an order of magnitude larger than typical metal-oxide-metal point contacts under zero-bias conditions, although with higher source impedance.
Reduction of ion sputtering yield by special surface microtopography
Authors: Ziegler J. F. , Cuomo J. J. , Roth J.
Published: February 2003

It is demonstrated that by covering a tungsten surface with tungsten needles, the sputtering coefficient for He ions is reduced by a factor of 3 to 100. Also, this metal surface does not blister under He bombardment to doses of 2.8×1019 He/cm2, although a similar polished W surface blisters at 1/30 this dose. Sputtering yields have been determined for both monoenergetic and distributed energy He ion beams, and the angular distribution of sputtered ions is reported.
Parametric amplification in arrays of Josephson tunnel junctions
Authors: Wahlsten S. , Rudner S. , Claeson T.
Published: February 2003

Arrays of 30 series-connected unbiased small Josephson tunnel junctions give parametric amplification at 10 GHz. A pump power of 10−8 W was required and gains of up to 24 dB were achieved. The gain was constant for a large range of signal power, up to a signal output power of 10 dB below the pump power. A maximum brightness temperature of 1.7×106 K, in a bandwidth of 12 MHz, was deduced from variations of the gain with input noise level.
Effects of ion-implanted atoms upon conduction electron spin resonance (CESR) in a Si : P system
Authors: Murakami K. , Masuda K. , Gamo K. , Namba S.
Published: February 2003

The behavior of the conduction electron spin resonance of ion-implanted (Si : P)  : Sb and (Si : P)  : Te systems is observed to be strongly modified by the presence of Sb or Te substitutional atoms in shallower surface layers; i.e., the ESR signal shows an anomalous line broadening. The origin of the anomalous broadening may be due to the spin-orbit interaction between the conduction electrons contained within a thin layer (⩽25 μm) and implanted Sb or Te impurities contained within a thin layer (.=.0.1 μm).
Magnetic bubble and stripe domain wall velocity in amorphous GdCoMo films
Authors: Hafner D. , Humphrey F. B.
Published: February 2003

The free bubble domain wall radial velocity and mobility in GdCoMo sputtered amorphous films has been measured and compared to stripe wall motion in the same sample. A sampling optical microscope with a sampling time of 10 nsec and a single exposure electronic recording TV system was used to observe the transient bubble size and stripe width. Wall velocities up to 400 m/sec were observed for applied fields up to 350 Oe. The velocity for some samples was linear with respect to drive although nonlinear behavior was also observed as well as domain distortion on the very temperature-sensitive samples. For the linear samples, a mobility of 1.95 m/sec Oe was measured in the effective drive field range 0–200 Oe.
Infrared laser spectroscopy of molecular beams
Authors: Gough T. E. , Miller R. E. , Scoles G.
Published: February 2003

A new technique suitable for infrared laser spectroscopy of molecular beams is presented and tested. The metod is based on the detection of the power absorbed, as a modulated increase of power carried by the molecules to a microcalorimeter (a cryogenic bolometer), after the molecular beam has been crossed with the modulated output of a semiconductor diode laser. Sensitivity, resolution, and possible applications are briefly discussed.
1500-h continuous cw operation of double-heterostructure GaInAsP/InP lasers
Authors: Shen C. C. , Hsieh J. J. , Lind T. A.
Published: February 2003

The first three double-heterostructure GaInAsP/InP diode lasers to be life tested have so far logged over 1500, 1100, and 700 h, respectively, of continuous cw operation at room temperature without degradation. Their emission wavelength is 1.15 μm.
Analysis of plasma-grown GaAs oxide films
Authors: Kauffman R. L. , Feldman L. C. , Poate J. M. , Chang R. P. H.
Published: February 2003

Thin oxide films of GaAs grown in a plasma have been analyzed using Rutherford backscattering and ion-induced x rays. Films whose thicknesses are greater than 1000 Å have a composition of O:Ga:As of 3:1.07:1. For the thinner films, the oxygen content is less indicating an incomplete oxidation.
Room-temperature cw operation of buried-stripe double-heterostructure GaInAsP/InP diode lasers
Authors: Hsieh J. J. , Shen C. C.
Published: February 2003

Two types of buried-stripe double-heterostructure GaInAsP/InP diode lasers have been fabricated. Room-temperature cw operation has been achieved for junction-defined devices emitting at 1.21 and 1.25 μm.
Measurement of stress gradients generated by electromigration
Authors: Blech I. A. , Tai K. L.
Published: February 2003

Stress gradients generated by electromigration in aluminum films were measured at 340 °C. The stresses were measured by combining x-ray topography to record the effects of the film stress and scanning electron microscopy to measure the information on the topographs. At the electromigration threshold the stress gradients of 200-μm-long stripes are 6×1010 dyn/cm3, corresponding to an effective charge of z*=−1.2.
Carrier removal rate for n-type and p-type silicon by fission-fragment irradiation
Authors: Kobayashi Hisao , Takami Yasukiyo , Ikeda Tetsuo
Published: February 2003

A spreading resistance technique was applied to measure carrier removal rate in silicon by fission-fragment irradiation. It was observed that the impurity concentration affected the initial carrier removal rate for both n- and p-type silicon. The experimental results suggest the formation of clusters in fission-fragment damage. The initial carrier removal rate was determined to be 9.4×105 and 3.9×105 cm−1 for n- and p-type silicon at 298 °K; the impurity concentration for both types of silicon was 1×1015 cm−3. It was found that fission fragments had produced at least two deep level acceptors and one deep level donor and their levels were Ec−0.37 eV and Ec−0.51 eV for n-type silicon and Ev+0.27 eV for p-type silicon.
Back-surface emitting GaAsxSb1−x LED’s (λ=1.0 μm) prepared by molecular-beam epitaxy
Authors: Cho A. Y. , Casey H. C. , Foy P. W.
Published: February 2003

Compositionally graded layers of GaAsxSb1−x have been grown on GaAs substrates by molecular-beam epitaxy. Planar Zn-diffused 50-μm-diam light-emitting diodes have been prepared in GaAs0.9Sb0.1. The 1.0-μm wavelength emission was taken out through the transparent GaAs substrate, and for a pulsed current of 100 mA, the external quantum efficiency was 0.1%.