bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherent uv from a TEA N2 laser system
Authors: Bergmann Ernest E.
Published: February 2003

A technique is described to couple and synchronize two transversely excited atmospheric (TEA) nitrogen lasers in an oscillator-amplifier configuration to obtain spatially coherent 1-nsec pulses at 337 nm with an energy/pulse of several hundred microjoules. The technique should be adaptable to other very high gain laser systems whose operation terminates so quickly as to render optical resonators impractical.
Theoretical absorption spectra for Ne+2, Ar+2, Kr+2, and Xe+2 in the near ultraviolet
Authors: Wadt Willard R. , Cartwright David C. , Cohen James S.
Published: February 2003

Near-ultraviolet absorption spectra for the I(1/2)u→II(1/2)g transition have been calculated for Ne+2, Ar+2, Kr+2, and Xe+2 using ab initio configuration interaction methods. The spectra are all similar except that the position of maximum absorption shifts to longer wavelength for the heavier rare gases. The absorption cross sections are tabulated at the wavelengths of the KrF, XeBr, XeCl, and XeF lasers.
Fiber-optical relay
Authors: Johnson M. , Ulrich R.
Published: February 2003

Metallic pads on optical fibers are heated by the absorption of light at the 1-μW–10-mW power level. Due to differential thermal expansion, the fibers bend, and, by misaligned coupling, modulate guided light signals. An optically operated relay, a narrow-band audio-frequency resonator, and a self-commutating optically powered oscillator are demonstrated.
Injection locking of a xenon fluoride laser
Authors: Goldhar J. , Dickie J. , Bradley L. P. , Pleasance L. D.
Published: February 2003

Operation of a XeF laser at high spectral power densities on transitions within a single vibrational band has been demonstrated. An electron-beam-controlled discharge XeF laser was operated as an injection-locked regenerative amplifier. A narrow-band signal from an étalon-tuned XeF laser was used to lock the regenerative amplifier. Competition between the various components of the emission spectrum was observed. Homogeneous extraction is observed within each vibrational band, indicating that the rotational cross-relaxation time is substantially faster than the radiative lifetime of XeF. Coupling between vibrational bands was not observed. These measurements indicate that the efficient extraction from XeF on a single rotational transition should be possible. The band at 351 nm was found to consist of components arising from at least two different vibrational bands. The transitions in the 353-nm band and one component of the 351-nm band share a common vibrational level in the upper electronic state. These observations are consistent with current vibrational assignments of the XeF spectrum.
Actively controlled SAW power divider
Authors: Crowley J. D. , Weller J. F. , Giallorenzi T. G.
Published: February 2003

The operation and construction of a new actively controlled SAW power divider is presented. The amount of power delivered to either of two outputs can be controlled with a voltage less than +30 V. The two essential components of this device are a SAW magic tee fabricated on yz LiNbO3 and an acoustoelectric phase shifter which uses silicon air-gap coupled to the LiNbO3.
Ion implantation distributions in inhomogeneous materials
Authors: Winterbon K. B.
Published: February 2003

The integral equation for ion-implantation range, damage, and ionization distributions in random media is generalized to allow nonuniform target materials. The generalization range equation is solved in the path-length approximation, using power-law cross sections, for a target consisting of two dissimilar half-spaces. There is a discontinuity in the distribution at the interface, proportional to the value of the distribution in the material the projectile is leaving; the constant of proportionality is evaluated explicitly.
Fluorescent liquid-crystal display utilizing an electric-field-induced cholesteric-nematic transition
Authors: Yu L. J. , Labes M. M.
Published: February 2003

An electric-field-induced cholesteric-nematic transition on a sample containing a europium chelate guest molecule of little or no polarization shows contrast ratios as high as 9 : 1 for its brilliant red (612 nm) fluorescence.
Two-step annealing of arsenic-implanted 〈111〉 silicon
Authors: Kannan V. C. , Casey D. D.
Published: February 2003

A dose dependence in the effectiveness of a two-step annealing procedure for As-implanted 〈111〉 silicon has been observed. The upper limiting dose for which two-step annealing is more effective than a single-step 900 °C anneal is ∼2×1015 As/cm2. Increasing the annealing temperature above 900 °C reduces the dose for which two-step annealing is more effective than single-step annealing.
The electrical and mechanical response of lithium niobate shock loaded above the Hugoniot elastic limit
Authors: Stanton P. L. , Graham R. A.
Published: February 2003

Z-cut lithium niobate has been subjected to shock loading over a wide stress range to determine the general character of its response. Unusual electrical and mechanical effects are observed.
The photothermophone, a device for absolute calibration of photoacoustic spectrometers
Authors: Murphy J. C. , Aamodt L. C.
Published: February 2003

A new device for the absolute calibration of cells for photoacoustic spectroscopy is described. Experimental results for a particular cell are reported.
Molecular-beam epitaxy (MBE) of In1−xGaxAs and GaSb1−yAsy
Authors: Chang Chin-An , Ludeke R. , Chang L. L. , Esaki L.
Published: February 2003

Films of In1−xGaxAs and GaSb1−yAsy over the entire composition ranges have been grown on (100) GaAs, InAs, and GaSb substrates by MBE. In situ observations by high-energy electron diffraction have revealed a variety of surface reconstructions and correlated the growth process with the lattice mismatch. The compositions are governed by the relative rates of In and Ga in In1−xGaxAs, but primarily by that of Sb in GaSb1−yAsy because of its dominant incorporation over As. In these alloys, Sn is found to be a donor throughout In1−xGaxAs but an amphoteric impurity in GaSb1−yAsy.
Relaxation of photoexcited carriers in GaAs
Authors: Mathur V. K. , Rogers S.
Published: February 2003

An experiment is described to measure directly the mean free lifetime of the photoexcited carriers in a semi-insulating crystal by monitoring its photoconductivity.
Image resolution of the scanning acoustic microscope
Authors: Weglein R. D. , Wilson R. G.
Published: February 2003

We have measured the spatial frequency response of an experimental scanning acoustic microscope (SAM) at 375 MHz, using an acoustic high-resolution reflection test target consisting of Au bars on a silicon substrate. Although the instrument resolves 1.6-μm line detail quite well, in favorable agreement with theoretical predictions, the shape of the spatial frequency response curve differs substantially from expectations.
Optical regeneration of aged WO3 electrochromic cells
Authors: Knowles T. J.
Published: February 2003

Continuously cycled display cells of evaporated WO3 on tin oxide show a progressive reduction in contrast with time. Partial restoration of the cells was observed when the WO3 was irradiated with uv, particularly if the cell was biased into the bleaching mode. The observed effect is consistent with optical depopulation and subsequent removal of trapped charge.
Short cavity dye laser excited by an electron beam-pumped semiconductor laser
Authors: Onstott J. R.
Published: February 2003

Laser emission has been observed from a thin-film solid solution of R6G in PMMA when excited by an electron-beam-pumped semiconductor laser. Both lasers are operated in the end-pumped configuration so that two-dimensional scannability of the dye laser emission is realized.
Laser action in copper with copper acetate as a lasant
Authors: Chakrapani G. , Rao T. A. Prasada , Murty A. A. N. , Ramachandra Rao D.
Published: February 2003

Laser action in copper at 5106 and 5782 Å is reported from double pulsed discharges with a new lasant, cupric acetate, at an optimum temperature of 230 °C. Several interesting laser characteristics observed as a function of temperature and delay between pulses are discussed for both transitions.
A tunable 1.1-μm fiber Raman oscillator
Authors: Lin Chinlon , Stolen R. H. , Cohen L. G.
Published: February 2003

A tunable 1.1-μm fiber Raman oscillator is reported. The oscillator is pumped by a cw mode-locked Nd : YAG laser at 1.064 μm. Wavelength tuning is obtained by using group velocity dispersion in a 600-m-long single-mode borosilicate fiber and subnanosecond pulses tunable from 1.101 to 1.125 μm are generated. The slope of the experimental tuning curve gives a group dispersion of 31 ps/nm km at 1.12 μm for the Raman fiber, in good agreement with the calculated value of combined material and waveguide dispersion.
Large-area uniform growth of 〈100〉 Si through Al film by solid epitaxy
Authors: Majni G. , Ottaviani G.
Published: February 2003

Epitaxial and uniform growth of a 0.6-μm-thick silicon layer was obtained in large areas at 530 °C by the dissolution and transport of an evaporated Si layer through an Al film using the Si/Al (evaporated)Si (evaporated) structure. Channeling measurements showed that the grown Si layers are well ordered and epitaxial with the underlying 〈100〉 substrate. The lateral uniformity is verified by scanning electron microscopy and electron microprobe measurements. Electrical measurements indicate that the grown layer is p type with 2×1018 cm−3 hole concentration and 65 cm2/V sec Hall mobility.
Dynamic simulation of normal zone evolution in a superconducting composite
Authors: Chen W. Y , Purcell J. R.
Published: February 2003

A numerical procedure has been implemented to dynamically simulate the evolution of a normal zone in a superconducting composite. The model has the nucleate/film boiling heat transfer of helium, the effect of current sharing, the conduction at the zone ends, and the temperature variation of the thermal conductivity and specific heat taken into consideration. Limiting recovery current density JL and heat flux QL are calculated. It was discovered that QL approaches 0.28 W/cm2 for long zones regardless of the conductor cooling surface to cross section ratio P/A, but can be much higher for short zones.
Elastic-surface-wave temperature coefficients of delay line with ZnO thin film
Authors: Nakagawa Yasuhiko
Published: February 2003

The elastic-surface-wave device with a zero first-order temperature coefficient has been fabricated on Pyrex glass by use of a ZnO thin-film overlay. The second-order temperature coefficient of ZnO/Pyrex glass was about 1.24 times as much as that of ST-cut quartz and was similar in sign. It is shown theoretically that the dispersion is very low at a ZnO film thickness of hK∼1.7, which gives a zero first-order temperature coefficient.
Dependence of absorption and optical contrast of a dichroic dye guest on the pitch of a chiral nematic host
Authors: Cole H. S. , Aftergut S.
Published: February 2003

Absorption of unpolarized light by a dichroic dye dissolved in a chiral nematic host increased with a decrease in pitch of the host, accompanied by a proportionate increase in contrast ratio, in qualitative agreement with a theoretical analysis by White and Taylor. Identical experimental values of order parameter of the guest-host system were obtained by two independent methods.
A new spectroscopic technique for imaging the spatial distribution of nonradiative defects in a scanning transmission electron microscope
Authors: Petroff P. M. , Lang D. V.
Published: February 2003

A new spectroscopic technique for imaging the spatial distribution of nonradiative defects in semiconductor materials is presented. The technique combines the versatility and sensitivity of deep-level transient spectroscopy (DLTS) with the capability for defect analysis at high resolution of the scanning transmission electron microscope. This scanning DLTS method (SDLTS) is illustrated by observing Cu-related defect centers in Ga1−xAlxAs epitaxial layers. A high sensitivity (3×1015 Cu defects cm−3 have been detected) and a spatial resolution of 2 μ or better illustrate the potential of the technique for the study of the electrical behavior of defects in semiconductor devices.
High-energy ions from a Nd-laser-produced plasma
Authors: Decoste R. , Ripin B. H.
Published: February 2003

Measurements of the asymptotic energy distribution of the different high-energy ion species at Nd-laser irradiance 1015–1016 W/cm2 on a CH2 planar target are presented and the acceleration mechanism of these high-energy ions is discussed. Multipeak structure between 10 and 100 keV is observed on the H+ ion distribution. A disproportionate number of H+ ions with E/Z higher than the C+z ions is also observed.
Formation and quenching kinetics of ArF
Authors: Rokni M. , Jacob J. H. , Mangano J. A. , Brochu R.
Published: February 2003

In this paper we report on the formation and quenching kinetics of ArF* (2Σ1/2). The ArF* is produced by irradiating mixtures of Ar and F2. The primary formation channel is via the recombination of Ar+ and Ar+2 with F−. Quenching of ArF* by F2 and Ar have been measured by analyzing the ArF* 2Σ1/2→2Σ1/2 fluorescence as a function of the F2 and Ar partial pressures. We have also measured the displacement of the Ar in ArF* by Kr and Xe to form KrF* and XeF*, respectively.
Laser emission from the 13.9-μm 1000→0110 CO2 transition in pulsed electrical discharges
Authors: Kasner W. H. , Pleasance L. D.
Published: February 2003

Laser emission on the Q and P branches of the 1000→0110 transition of CO2 has been observed in a system using a cryogenically cooled pulsed electrical discharge as the excitation source. This is the first reported evidence that an inversion on this transition can be produced by direct electrical excitation of a gas mixture containing CO2. The inversion is created by using a delayed 10.6-μm laser pulse to saturate the 1000 state. Parameter ranges for the system operating in an optimal CO2 : N2 : He=1 : 2 : 25 gas mixture are as follows: pressure, 5–18 Torr; temperature, 140–220 °K; time delay of 10.6-μm laser pulse, 0.1–4 msec; and output energy, 15–20 μJ/pulse.
Sealed TEA CO2 lasers with external control of gas chemistry
Authors: Willis C. , Back R. A. , Purdon J. G.
Published: February 2003

The chemistry of gas mixtures for high-power pulsed TEA CO2 lasers can be controlled by using a gas recirculation system which includes a device to recombine the CO and O2 formed by the discharge-induced decomposition of the CO2. This gives low steady-state levels of CO and O2 and eliminates laser failure due to excessive arcing. Lasers which normally fail after a few hundred pulses when sealed have been run with this system for approximately 106 pulses without failure. This development allows the use of isotopic mixtures of CO2 as laser media without impossibly high costs.
A tunable multiple Stokes cw fiber Raman oscillator
Authors: Jain R. K. , Lin Chinlon , Stolen R. H. , Ashkin A.
Published: February 2003

A broadly tunable source of coherent cw radiation has been achieved by the use of a multiresonant cavity for multiple Stokes oscillation in a fused-silica fiber Raman oscillator. Each order of tunable Stokes emission acts as a pump for the next higher order; a net tunability of several times the intrinsic Raman gain bandwidth is obtained. With 8 W of 5145-Å pump radiation coupled into a 100-m-long single-mode fiber, four orders of Stokes oscillation have been obtained, yielding over 350 Å of tuning in the 5200–5660-Å spectral range.
Electrochromism in the composite material Au-WO3
Authors: Sichel E. K. , Gittleman J. I. , Zelez J.
Published: February 2003

We have produced for the first time an electrochromic cermet composed of Au grains dispersed in the electrochromic WO3. The electrochromism arises from a shift in the wavelength of the dielectric absorption characteristic of gold cermets. The shift is due to a change in the dielectric constant of the WO3 matrix as a result of the coloring process. This is to be contrasted with the coloring in pure WO3 which results from the appearance of a broad absorption band in the red and infrared.
Raman scattering and zone-folding effects for alternating monolayers of GaAs-AlAs
Authors: Merz J. L. , Barker A. S. , Gossard A. C.
Published: February 2003

Raman scattering results have been obtained from alternating monolayer structures of GaAs and AlAs fabricated synthetically by molecular beam epitaxy. Frequency shifts of the principal phonons have been observed, as well as new vibrational modes which result from zone-folding effects. The results suggest that ∼20–30% of the cation sites in the interface regions are disordered.
Niobium point-contact Josephson-junction behavior at 604 GHz
Authors: Weitz D. A. , Skocpol W. J. , Tinkham M.
Published: February 2003

We have measured the ac Josephson effect in Nb point contacts at 604 GHz (496 μm). We find the coupling of the far-infrared radiation to the point contact to depend in a simple manner on the resistance of the contact. The behavior of the high-resistance point contacts (50⩽R⩽200 Ω) is very reproducible, allowing a quantitative comparison of the data to the frequency-dependent Werthamer theory. We also account for the effects of noise and heating and compare these to Tinkham’s heating theory.
A double-layered encapsulant for annealing ion-implanted GaAs up to 1100 °C
Authors: Lidow A. , Gibbons J. F. , Magee T.
Published: February 2003

A double-layered encapsulation consisting of a 1000-Å plasma-deposited Si3N4 layer under a 3000-Å CVD SiO2 layer doped with arsenic has been used to anneal selenium ion-implanted GaAs at temperatures up to 1100 °C with no signs of mechanical failure when examined with a scanning electron microscope. Significant improvement in electrical activation of implanted layers over simple Si3N4 layer caps has also been observed at lower temperatures.
Pinch dynamics in diodes using foil anodes
Authors: Gilad P. , Miller S. , Zinamon Z.
Published: February 2003

It is demonstrated that electron-beam collapse in a diode using a thin foil anode takes place considerably faster than in a diode using a thick anode. The effect is shown to follow from earlier ion emission from a thin anode as well as from the different nature of the electron trajectories in that case. Applications for pellet fusion and for obtaining very high energy densities in matter are suggested.
Increasing the ion beam current from a multidipole source
Authors: Leung K. N. , Collier R. D. , Taylor G. R. , Kribel R. E.
Published: February 2003

The ion beam current from a multidipole source can be increased by the injection of low-energy primary electrons. By optimizing the injection energy, an increase in beam current of approximately 35% has been achieved.
A transversely excited multiatmosphere CO2 waveguide laser
Authors: Gibson A. F. , Rickwood K. R. , Walker A. C.
Published: February 2003

A CO2 waveguide laser with a silicon cathode is described. Laser action can be obtained at pressures over 4 atm without preionization. At atmospheric pressue specific outputs as high as 5 J/l have been obtained, and the laer operated at pulse repetition frequencies up to 1 kHz.
Laser action on the B2Σ+1/2→X2Σ+1/2 band of HgCl at 5576 Å
Authors: Parks J. H.
Published: February 2003

This letter describes a new laser operating on the B2Σ+1/2→X2Σ+1/2 band of HgCl at 5576 Å. Pumping was achieved by high-intensity electron-beam excitation of high-pressure rare-gas mixtures containing small amounts of Hg and CCl4. A lower bound to the efficiency was determined to be 0.5% in an unoptimized configuration, and higher efficiency is expected.
The suppression of internally circulating modes in (GaAl)As/GaAs heterostructure lasers and their effect on catastrophic degradation and efficiency
Authors: Henshall G. D.
Published: February 2003

Premature catastrophic degradation in sawn-cavity (GaAl)As/GaAs heterostructure lasers can be attributed to the presence of internally circulating modes. When lasers were selected for good near-field uniformity and assumed freedom from internally circulating modes, good agreement was obtained between the power at catastrophic degradation and the effective optical width perpendicular to the junction.
Observation of the transferred-electron effect in GaxIn1−xAsyP1−y
Authors: Hayes R. E. , Raymond R. M.
Published: February 2003

Transferred-electron oscillation in devices employing GaxIn1−xAsyP1−y as the active material has been observed. An oscillation threshold average field of (5.5–8.6) ×103 V/cm was determined for 1.05-eV band-gap material having x and y values of approximately 0.13 and 0.37, respectively. A pulsed device had an efficiency of 0.5% at 27.49 GHz.
Collisional transitions obeying nondipolar selection rules between M levels of FCN, a laser-microwave double-resonance study
Authors: Jones Harold
Published: February 2003

Two Stark components of the R (2) transition of the ν1 band of FCN were tuned into resonance with the R (20) 9.4-μm CO2 laser line. From consideration of the collisionally induced double-resonance signals observed in the microwave spectrum, it was concluded that ΔJ=0, ΔM=±1 nondipolar collisional transitions occur with a frequency similar to that of the dipole-allowed ΔJ=±1, ΔM=±1 collisional transitions.
A high-power tunable laser for the 9–12.5-μm spectral range
Authors: O’Neill F. , Whitney W. T.
Published: February 2003

We have demonstrated continuous tunability of a high-pressure molecular gas laser over portions of the 9–12.5-μm spectral range. The laser employs electron-beam-controlled multiatmosphere discharges in He : N2 : CO2, He : CO : N2O, or He : CO : CS2. The high-pressure CS2 laser is continuously tunable in the 12.1-μm region which is relevant for laser separation of uranium isotopes.
Double-heterostructure GaAs-GaAlAs injection lasers on semi-insulating substrates using carrier crowding
Authors: Lee C. P. , Margalit S. , Yariv A.
Published: February 2003

GaAs-GaAlAs double-heterostructure lasers were fabricated on semi-insulating substrates. Laser action based on carrier confinement via the crowding effect has been demonstrated. Laser action takes place in a narrow (10–20 μm) region near the edge of the mesa where the current is injected. The threshold current is low and is comparable to that of stripe-geometry lasers.
Thermally stimulated currents in epitaxially grown selenium monocrystalline films
Authors: El-Azab M. I. , Champness C. H.
Published: February 2003

Thermally stimulated currents have been measured at liquid-nitrogen temperature in structures containing a monocrystalline selenium thin film in the (0001) orientation. The results indicate a total trap density of the order of 1020 cm−3. Decayed TSC results suggest trapping energies over a range of values up to 0.16 eV.
Laser action on the B2Σ+1/2→X2Σ+1/2 band of HgBr at 5018 Å
Authors: Parks J. H.
Published: February 2003

This letter describes a new laser operating on the B2Σ+1/2→X2Σ+1/2 band of HgBr at 5018 Å. Pumping was achieved by high-intensity electron-beam excitation of high-pressure Ar/Xe mixtures containing small amounts of Hg and HBr. A lower bound to the efficiency was determined to be 0.25% in an unoptimized configuration, and higher efficiency is expected.
Enhanced production of coherent vuv radiation by four-wave mixing in Sr vapor
Authors: Bjorklund G. C. , Bjorkholm J. E. , Freeman R. R. , Liao P. F.
Published: February 2003

Significant enhancement of the unsaturated conversion efficiencies of four-wave sum frequency mixing processes involving autoionizing states in Sr vapor is obtained by utilizing the 5s7s 1S0 two-photon channel and phase matching by frequency adjustment. Extrapolation to low power levels indicates that production of cw vuv radiation may be possible. A saturation effect arising from depletion of one of the fundamental beams by two-photon absorption is observed.
The dynamics of radiation blistering and near-surface deuterium retention in deuteron-irradiated copper
Authors: Johnson P. B. , Armstrong T. R.
Published: February 2003

The effect of radiation blistering on the retention of deuterium in the near-surface region of 200-keV d+ irradiated Cu at 350 K has been studied. Blistering is detected using an in situ method based on the scattering of laser light. The incident deuteron beam is used both for implantation and to obtain the dynamic deuterium depth profile. Discrete blisters of approximately 4-μm average diameter are found to form rapidly at a well-defined fluence of (7±1) ×1018d+/cm2. The rate deuterium accumulates in the first 0.4 μm is found to fall dramatically at the onset of blistering from a steady value, of ∼2% of the implantation rate, to nearly zero. Typical D : Cu loadings at the critical dose for blistering are ∼1 at.%.
Recombination lasers in expanding CO2 laser-produced plasmas of argon, krypton, and xenon
Authors: Silfvast W. T. , Szeto L. H. , Wood II O. R.
Published: February 2003

Laser oscillation has been observed in the expansion phase of transversely initiated laser-produced plasmas of argon, krypton, and xenon at pressures up to 1 atm. All of the experimental evidence indicates that these lasers are of a plasma-recombination type in which an initially ionized plasma rapidly expands and cools, leading to a high recombination rate and subsequently to an inversion in the next lower ionization stage.
Quasisimultaneous SIMS-AES-XPS investigation of the oxidation of Ti in the monolayer range
Authors: Benninghoven A. , Bispinck H. , Ganschow O. , Wiedmann L.
Published: February 2003

In order to calibrate previous secondary ion mass spectrometry (SIMS) measurements on various oxidized metal surfaces in terms of oxygen coverage, quasisimultaneous SIMS, AES, and XPS have been applied to several metal-oxygen systems. First, results are given for the Ti-O system. In this case, the oxygen signals obtained with the three methods show an identical dependence on the oxygen exposure and can therefore be used for establishing a coverage scale. The successive stages of oxidation lead to significant changes of first the AES, then the SIMS signals, and finally a chemical shift in XPS.
Method of separating hysteresis effects from MIS capacitance measurements
Authors: Nakagawa T. , Fujisada H.
Published: February 2003

A new method is proposed to estimate interface state density in hysteretic MIS devices. In this method, a narrow bias-voltage swing is applied around a certain center bias voltage to obtain a narrow C-V curve without hysteresis. It is shown that the capacitance derivative obtained in this way depends on MIS capacitance only, and then can be used for determining the interface state density in the hysteretic InSb MIS devices.
Impurity gradients caused by surface states and substrate doping in epitaxial GaAs
Authors: Wolfe C. M. , Nichols K. H.
Published: February 2003

A model is developed for the incorporation of donors and acceptors in epitaxial GaAs which indicates that the thin p-type region often observed at the layer-substrate interface in n−p+ structures is caused by the electric field associated with surface states and substrate doping. The model also predicts impurity gradients at the outer surface, about which little is known experimentally. Since results from the model are in agreement with many experimental observations, surface states and substrate doping are believed to be the major cause of impurity gradients in epitaxial GaAs.
High-frequency limitations of the double-junction SQUID amplifier
Authors: Zimmerman J. E. , Sullivan D. B.
Published: February 2003

The double-junction SQUID is viewed as a parametric amplifier and mechanisms, which place an upper limit on the pump frequency (and thus gain), are investigated. Self-induced steps in the I-V characteristics as well as damping of the Josephson oscillation are shown to be two limiting mechanisms.
Nature of 〈110〉 dark-line defects in degraded (GaAl)As-GaAs double-heterostructure lasers
Authors: Ishida Koichi , Kamejima Taibun , Matsui Junji
Published: February 2003

The 〈100〉 dark-line defects (DLD’s) in the degraded (GaAl)As-GaAs double-heterostructure lasers are studied by transmission electron microscopy. Two types of 〈110〉 DLD’s are observed; one is associated with 〈110〉 straight dislocations and the other with dislocation networks developing from the mirror surface. The former type of the 〈110〉 DLD’s is found to be formed by dislocation glide motion. The development of the 〈100〉 dislocation dipole from the 〈110〉 dislocation is also observed, indicating that the 〈110〉 dislocation is a source of the 〈100〉 dislocation dipole.
Tunable cw laser operation in F
B (II) type color center crystals
Authors: Litfin G. , Beigang R. , Welling H.
Published: February 2003

cw laser action in Na+-doped KCl and RbCl crystals containing FB(II) centers is reported. The total tuning range was 2.25⩽λ⩽2.9 μm. Pump power at threshold was measured to be 20 mW and an output power of 18 mW was obtained. It is expected that the wavelength range for this type of laser can be extended into the 3–4-μm region with RbBr and RbI crystals.
Growth of single-crystal sapphire-clad ruby fibers
Authors: Burrus C. A. , Coldren L. A.
Published: February 2003

Single-crystal Cr-doped Al2O3 fibers can be grown by a floating-zone technique from small source rods locally melted at the end by a CO2 laser. By using the same laser to melt and regrow only the surface of the fiber, the Cr concentration in this surface layer can be reduced by a factor of 100 or more by selective evaporation.
A new interferometric alignment technique
Authors: Flanders D. C. , Smith Henry I. , Austin Stewart
Published: February 2003

A new interferometric alignment technique has been developed that is suitable for aligning x-ray lithography masks or photomasks relative to a substrate. A superposition precision of 200 Å has been demonstrated and in principle ∼100 Å should be possible. The superposition of matching grating type alignment marks on facing plates is determined from the intensities of beams multiply diffracted from the matching alignment marks. The principle of the interferometric alignment technique is described.
Electro-optic effects of PLZT thin films
Authors: Ishida Makoto , Matsunami Hiroyuki , Tanaka Tetsuro
Published: February 2003

It is demonstrated that thin films of PLZT prepared by rf sputtering exhibit an electro-optic effect. The effects are measured using the reflection of the light polarized with the electric vector parallel to the incidence plane of the light. The reflected light intensity changes with the electric field and shows a decrease of about 33% at 12.5 kV/cm, when the light is incident at 70°. This technique turns out to be useful for the measurements of the electro-optic effects of thin films, and the results suggest the possibility of a reflection-type light modulator consisting of a thin film.
The memory effect of ZnS : Mn ac thin-film electroluminescence
Authors: Marrello V. , Rühle W. , Onton A.
Published: February 2003

The electroluminescence of ZnS : Mn thin-film memory devices is observed to occur in two components, one which is spatially homogeneous and one from localized bright regions less than ∼1 μm in diameter. The brightness-voltage hysteresis, or memory effect, is observed to reside exclusively in the luminescence of the localized bright regions in our devices. It is concluded that the memory effect arises from a negative resistance of a filamentary ac conduction mechanism in these regions.
Cast polycrystalline silicon Schottky-barrier solar cells
Authors: Lillington D. R. , Townsend W. G.
Published: February 2003

Measurements have been made of the electrical and optical properties of polycrystalline metal-insulator-semiconductor Schottky-barrier solar cells (MIS SBSC’s) formed by the evaporation of aluminum onto Wacker ’’Silso’’ cast p-type silicon substrates. Results show that consistently high AM1 efficiencies of over 8% may be achieved using this material and that the V-I characteristics are stable over the period of testing. The short-circuit current of these devices (∼22 mA cm−2) indicates that grain-boundary recombinationn is not a serious problem.
The charging process in the acoustic surface wave p-n diode storage correlator
Authors: Borden P. , Kino G. S.
Published: February 2003

We demonstrate analytically and experimentally that the acoustic surface wave p-n diode storage correlator may be charged either very quickly or very slowly, depending on the input signal levels, and independent of the diode storage time. Thus, the same long storage time device is usable for both high-speed and slow (such as integrating) applications.
Spontaneous anti-Stokes scattering as a high-resolution and picosecond-time-scale vuv light source
Authors: Harris S. E.
Published: February 2003

A vuv and soft x-ray light source based on spontaneous anti-Stokes scattering from atomic population stored in a metastable level is proposed. It is shown that the source has a maximum brightness equal to that of a blackbody at a Boltzman temperature characteristic of the population of the metastable level. This maximum brightness is attained as the media approaches two-photon opacity. The source should have high resolution, may be of picosecond time scale, and on a pulsed basis should be brighter than other laboratory-scale vuv light sources.
Micromechanical light modulator array fabricated on silicon
Authors: Petersen K. E.
Published: February 2003

A micromechanical device is described which consists of a thin metal-coated SiO2 membrane fabricated on an ordinary silicon wafer using techniques compatible with IC processing. The membrane can be deflected electrostatically over large angles (≳5°), at high frequencies (≳40kHz), at least 1010 times without breaking or any noticeable deterioration due to fatigue. A number of adjacent devices have been used as a 16-element light modulator array in a small display system. Calculations of performance parameters are in good agreement with experiment. Advantages of this device over similar previous deformagraphic systems are IC compatibility, good voltage sensitivity, high speed, higher deflections with less fatigue, well-established fabrication techniques, and the possibility of integrating driving and decoding circuitry on the same chip as the modulators. In addition, the complexities of a vacuum environment and e-beam addressing are avoided.
Selenium implanation into silicon studied by DLTS technique
Authors: Richou F. , Pelous G. , Lecrosnier D.
Published: February 2003

Deep-level transient spectroscopy (DLTS) has been used to determine the activation energy and spatial distribution of the electron traps introduced n-type silicon implanted with 5×1010Se ions/cm2 at 800 keV. Radiation damage levels were demonstrated to be present up to a 600 °C anneal. After 700 °C anneal, two deep levels were found at Ec−0.225 eV and Ec−0.485 eV. The in-depth distributions of the Ec−0.225 eV level after 600 °C anneal and of the two levels after the 700 °C anneal were determined. So, it was found that selenium is a fast diffuser and that each implanted Se ion forms one trap with two levels.
Elimination on electron multipacting in superconducting structures for electron accelerators
Authors: Lyneis C. M. , Schwettman H. A. , Turneaure J. P.
Published: February 2003

Electron multipacting in a 2.8-GHz TM010-mode anodized niobium test cavity at 1.4 K has been studied experimentally. An electron multipactor simulation computer program, which we developed, successfully calculates the multipactor field levels and multipactor location observed experimentally and also provides additional details of the multipactor phenomena. With the multipactor simulation program, a sharp-cornered TM010-mode cavity has been designed in which multipacting is greatly reduced. A subsequent experiment on such a sharp-cornered anodized niobium cavity has shown that electron multipacting is in fact eliminated for this cavity up through the highest field achieved. This work has shown that, with a simple modification in geometry, multipacting can probably be eliminated in the superconducting structure for the Stanford electron accelerator.
High-efficiency GaAs shallow-homojunction solar cells
Authors: Bozler Carl O. , Fan John C. C.
Published: February 2003

Conversion efficiencies as high 15.3% (17% when corrected for contact area) have been obtained for single-crystal antireflection-coated GaAs solar cells fabricated without the use of Ga1−xAlxAs layers. These devices employ a thin n+/p/p+ structure prepared by chemical vapor deposition, in which surface recombination losses are reduced because the n+ layer is so thin (1300 Å) that most of the carriers are generated in the p layer below the junction.
Effect of substrate temperature on the microstructure of thin-film silicide
Authors: Köster U. , Tu K. N. , Ho P. S.
Published: February 2003

The effect of substrate temperature Ts during evaporation on the microstructure of Pd2Si thin films on (111) Si formed by evaporation followed by subsequent higher-temperature anneal has been investigated by transmission electron microscopy. For Ts of 20 and 100 °C, the Pd2Si grows epitaxially on the substrate. For a Ts of 200 °C the Pd2Si is polycrystalline and grains are uniaxially textured about the [001] axis and there are pinholes in the film. For a Ts of 300 °C, the microstructure of Pd2Si is spongy and grains are much less oriented.
The expansion velocities of laser-produced plasmas determined from extreme ultraviolet spectral line profiles
Authors: Feldman U. , Doschek G. A. , Behring W. E. , Cohen Leonard
Published: February 2003

The expansion of laser-produced plasma is determined from the shapes of spectral lines of highly ionized iron emitted in the extreme ultraviolet. The plasmas were produced by focusing the pulse from a Nd : glass laser onto solid planar targets, and spectra were recorded with a high-resolution grazing incidence spectrograph. From the Doppler broadening of lines of Fe XX and Fe XXI, expansion velocities of ∼830 km s−1 were determined. The relative time-averaged ion abundances of Fe XVIII, Fe XIX, Fe XX, and Fe XXI are estimated for three different spectra. The abundances do not differ by more than a factor of 4 for any of the spectra.
Plasmon-loss satellites in Auger spectra of alloy surfaces
Authors: Sun T. S. , Chen J. M. , Viswanadham R. K. , Green J. A. S.
Published: February 2003

Grain-boundary surfaces of Al-Zn-Mg alloys have been studied with Auger electron spectroscopy. Particular emphasis was given to plasmon loss satellites in the Auger spectrum. It is found that the plasmon energy losses associated with Al, Zn, and Mg Auger peaks are different, and the energy losses vary with heat treatment of the alloy. These variations provide information on chemical composition and nonhomogeneities in an alloy, such as precipitation and segregation. It is shown that, at the grain boundary of aged specimens of the Al alloy, the Zn atoms are all in the form of MgZn2 precipitates, but only about 40% of the total Mg is in the precipitates. The other 60% is situated outside of the precipitates.
Changes in x-ray diffraction patterns of polyvinylidene fluoride due to corona charging
Authors: Das Gupta D. K. , Doughty K.
Published: February 2003

The changes in the x-ray diffraction patterns of 16- and 25-μm-thick polyvinylidene fluoride films, caused by 6-kV corona charging at room temperature, are presented. The diffraction peaks corresponding to (100) and (020) α-crystalline forms tend to be considerably reduced while the (110) β-form peak changes in shape and position.
Overtone bands lasing at 2.7–3.1 μm in electrically excited CO
Authors: Bergman R. C. , Rich J. W.
Published: February 2003

Lasing on the first overtone vibrational-rotational transitions of carbon monoxide is reported. The laser is a supersonic flow laser, which uses an electric-discharge-excited CO/He/O2 mixture. 20 W cw power at 0.6% electrical efficiency is obtained.
Fabrication-related effects in metal-ZnO-SiO2-Si structures
Authors: Cornell M. E. , Elliott J. K. , Gunshor R. L. , Pierret R. F.
Published: February 2003

Experimental results are presented which show that the nonideal nature of electrical characteristics derived from metal-ZnO-SiO2-Si structures, structures of the type proposed in surface-acoustic-wave applications, is due in large part to a deterioration of the Si-SiO2 subsystem during the thin-film ZnO deposition procedure. The thermally assisted breaking of surface-state bonds and radiation damage are identified as the sources of the deterioration. Progress achieved to date in reducing the cited damage, including the use of radiation-hardened SiO2 films and a low-temperature O2 anneal, are also described and discussed.
IV-VI semiconductor lateral-collection photodiodes
Authors: Holloway H. , Hurley M. D. , Schermer E. B.
Published: February 2003

The lateral-collection photodiode (LCP) is a novel device in which the p-n junction of a conventional photodiode is replaced by a matrix of small p-n junctions that collect photogenerated minority carriers from the intervening region. The LCP offers reduced capacitance and, in some cases, increased detectivity. IV-VI semiconductor LCP’s for the 3–5-μm spectral region show a capacitance reduction by up to a factor of 20 and a Johnson-noise-limited detectivity increase by up to a factor of 3 relative to a conventional photodiode in the same material.
High-power subnanosecond pulses from an injection mode-locked multiatmosphere CO2 oscillator
Authors: Corkum P. B. , Alcock A. J. , Rollin D. F. , Morrison H. D.
Published: February 2003

A dye laser controlled semiconductor reflection switch has been used to gate subnanosecond pulses of 10.6-μm radiation from the output of a ∼1-W cw CO2 laser. Upon injection into a multiatmosphere CO2 oscillator, high-power mode-locked pulses having a duration ≲200 ps and a peak single pulse energy ≳10 mJ were obtained. Synchronization of individual mode-locked dye laser and CO2 pulses has also been demonstrated.
Optical gain at 1.06 μm in the neodymium chloride-aluminum chloride vapor complex
Authors: Jacobs Ralph R. , Krupke William F.
Published: February 2003

First observation of optical gain for trivalent rare-earth molecular vapors is reported. Specifically, gain coefficients a few tenths percent/cm have been measured in the neodymium chloride—aluminum chloride vapor complex at 1.06 μm for the Nd3+ : 4F3/2→4I11/2 transition. The corresponding stored energy density at this wavelength is ≈35 J/l. The observed inversion lifetime of ≳10 μsec is interpreted to be dominated by near-resonant excited-state–excited-state binary collisions. Use of trivalent rare-earth molecular vapors as gain media in fusion laser amplifiers is discussed.
Optical saturation characteristics of CH3OCH3 and CCl3F
Authors: Kung R. T. V. , Sirchis M.
Published: February 2003

Saturation characteristics of CH3OCH3 and CCl3F were investigated in the intensity range 107 to 5×108 W/cm2 using a nanosecond CO2 laser. The ratio of the low-intensity absorption cross section to high-intensity absorption cross section ranges between 3 and 6 for the CO2 10.6-μm P (22) laser line, indicating substantial saturation at high-intensity levels. Rotational relaxation rate constants were inferred from the measured transmission as a function of pressure.
CO2 laser irradiation of solid targets in strong magnetic fields
Authors: Halverson W. , Loter N. G. , Ma W. W. , Morrison R. W. , Karmendy C. V.
Published: February 2003

Gain-switched CO2 laser pulses of 225 J were focused onto planar carbon targets in the presence of longitudinal magnetic fields up to 105 kG. For fields above 25 kG, the mass loss and cross-sectional area of the cylindrical blow-off plasma varied as B−6/5. For these cases, only the 60-nsec gain-switched laser spike caused target damage; the 1.5-μsec tail was absorbed by a ∼100-eV partially confined plasma extending several cm from the target. The field dependence of the plasma cross section is consistent with an adiabatic expansion against the magnetic field.
Pressure-induced compensation in n-type AgInSe2
Authors: Jayaraman A. , Tell B. , Maines R. G.
Published: February 2003

The pressure dependence of resisitivity of n-type AgInSe2 has been investigated up to 40 kbar hydrostatic pressure. The resisitivity shows a slight increase with pressure up to 26 kbar but exhibits a phenomenal time-dependent rise in the region between 28 and 32 kbar. The sample resisitivity rises by a factor of 2×106 before saturating. We believe that this effect is due to the formation of compensating defect centers in the crystal, prior to the sluggish transformation from the chalcopyrite to the NaCl-type structure.
Generation of synchronized cw trains of picosecond pulses at two independently tunable wavelengths
Authors: Jain R. K. , Heritage J. P.
Published: February 2003

We report the generation of synchronized trains of picosecond pulses at two independently tunable wavelengths from cw mode-locked dye lasers, synchronously pumped by a mode-locked argon-ion laser (pulse width∼100 psec). This has been achieved both by two-wavelength operation of a single Rhodamine 6G dye laer and by synchronously pumping two independent (Rh-6G) dye lasers. For both cases, with typical pulse widths of ≈ 5 psec at two independently tunable wavelengths, cross-correlation measurements indicate good synchronization, with a jitter of less than ∼10 psec between the two pulse trains.
Silane purification via laser-induced chemistry
Authors: Clark John H. , Anderson Robert G.
Published: February 2003

PH3, AsH3, and B2H6 have been removed from SiH4 by means of selective photolysis with an ArF uv laser. The absolute absorption cross sections for SiH4, PH3, AsH3, and B2H6 have been determined over the region 190–200 nm. Quantum yields for destruction of the contaminant species have been measured at 193 nm. The effects of free-radical reactions subsequent to photolysis on the selectivity of removal of PH3, AsH3, and B2H6 were found to be minimal. These results suggest that the purification of SiH4 via a laser-induced chemical process may be of considerable practical importance.
Curved junction stabilized filament (CJSF) double-heterostructure injection laser
Authors: Figueroa Luis , Wang Shyh
Published: February 2003

We have fabricated a new type of channel stripe laser with a curved active region which has a spatially stabilized output for measurements up to 2ITh (Pout=75 mW/facet). The CJSF laser has excellent lateral and longitudinal mode selectivity. The laser operates in almost single longitudinal mode when the current exceeds 1.1ITh. Zeroth-order lateral mode operation is obtained for currents less than 1.5ITh (Pout=30 mW/facet) and linear power output for measurements up to 2ITh. We attribute the favorable characteristics to the curvature of the grown layers which leads to the stabilization of the lateral modes.
Critical currents associated with the interaction of commensurate flux-line sublattices in a perforated Al film
Authors: Fiory A. T. , Hebard A. F. , Somekh S.
Published: February 2003

The flux-flow critical current as a function of transverse magnetic field for an oxygen-doped Al film perforated with a two-dimensional triangular lattice pattern of holes shows pronounced structure at harmonically related values of the applied magnetic field. Effects at thecharacteristic fields are interpreted in terms of the interaction between commensurate flux-line sublattices, one of which is strongly pinned to the holes by the vortex-hole coupling force and the other of which is located interstitially between the hole-lattice sites. A model is proposed for the vortex-hole coupling force which, in conjunction with a treatment of vortex-vortex interactions, qualitatively accounts for the observed temperature and field dependence of these harmonically related critical currents.
Electro-optic scanning of light coupled from a corrugated LiNbO3 waveguide
Authors: Hong C. S. , Yariv A. , Chen B.
Published: February 2003

Light diffracted from a grating output coupler in a Ti-diffused LiNbO3 waveguide is scanned electro-optically. Using a coupling length of 2.5 mm in our arrangement we have demonstrated a scanning capability of one resolved spot per 3 V/μm applied field.