bluuebunny/crossref_metadata_2025 huggingface dataset:
Near-atmospheric-pressure xenon excimer laser
Authors: Turner C. E.
Published: February 2003

Oscillation at 172 nm for 200 nsec has been observed at a pressure of 1.5 atm of xenon with a 1-m length of gain medium pumped by a 200-kV 7-A/cm2 1-μsec electron beam. The observed behavior agrees with calculations based on the excited-state mixing model for this new operating regime. The results support model predictions that a modest increase in excitation rate (about a factor of 2) would yield quasi-steady-state laser oscillation with an intrinsic efficiency near 5%, a fluence of ∼1 J/cm2, and a peak intracavity two-way flux of ∼50 MW/cm2. In optimized laser amplifier designs, significantly higher amplifier efficiencies should be possible.
High-speed holography of laser-induced breakdown in liquids
Authors: Lauterborn W. , Ebeling K. J.
Published: February 2003

The phenomenon of ruby laser-induced breakdown in liquids is investigated by high-speed holography. The advantage of using holography instead of ordinary photography lies in the possibility to easily suppress the bright white light emitted during the breakdown process. This light constitutes an incoherent background on the holographic plate and does not reproduce upon reconstruction of the recorded scene.
Barrier tunneling as a possible efficient pump for exciplex gas lasers
Authors: Bennett W. R.
Published: February 2003

It is suggested that quantum-mechanical tunneling might be used in some instances to provide efficient two-body collision formation of quasibound molecular states suitable for exciplex laser systems. Some evidence for the existence of the necessary bumps in the molecular potential curves is discussed, and it is noted that potential bumps of the general magnitude and width required are apt to be produced whenever an appreciable cross section exists for endothermic excitation transfer from a metastable state of one gas to an excited state of another gas.
Hall-effect determination of the N-trap bound state in GaAs1−xPx
Authors: van Ruyven L. J. , Bluyssen H. J. A. , van der Heijden R. W. , Tan T. B. , Ralph H. I.
Published: February 2003

Hall-effect measurements as a function of temperature on nitrogen-containing GaAs1−xPx have shown that the nitrogen isoelectronic trap in these materials can be best described by a bound state in the band gap, occupied by electrons according to the equilibrium thermal distribution. It is shown that the presence of nitrogen can have a pronounced effect on the free-carrier density. Our results are in excellent agreement with recent optical data.
Tunnel triode—a tunneling base transistor
Authors: Chang L. L. , Esaki L.
Published: February 2003

Proposed is a triode structure made of semiconductor heterojunctions where carriers of one type tunnel through the base region to which carriers of the other type are confined. In1−xGaxAs and GaSb1−yAsy alloys are candidates for this heterostructure. As a three-terminal amplifier, the device is expected to exhibit high impedances for both input and output, a large current gain, and a marked improvement in high-frequency peformance.
Silicon epitaxy by solid-phase crystallization of deposited amorphous films
Authors: Roth John A. , Anderson C. Lawrence
Published: February 2003

We report the solid-phase growth of epitaxial Si thin films by the heating of amorphous Si deposited onto atomically clean (100) Si substrates at room temperature. Epitaxial Si layers ranging in thickness from 1000 to 5000 Å have been grown by heating the amorphous films in ultrahigh vacuum to temperatures of 500–600 °C. Good crystal quality of the layers grown by this method has been demonstrated by Rutherford backscattering and transmission electron microscopy.
A new method determining migration distance of electrons and holes in insulators
Authors: Ozawa Lyuji
Published: February 2003

It is proposed that the average migration distance L of electrons and holes in insulators can be determined from electron-hole recombination at activator ions acting as internal and radiative recombination centers. This is demonstrated for Y2O3. One-dimensional migration (along a line) rather than three-dimensional spreading is found; L = dC−1, where d is the cation-cation distance and C is the activator concentration in mole fraction.
Chemical microanalysis by x-ray microscopy near absorption edge with synchrotron radiation
Authors: Polack F. , Lowenthal S. , Petroff Y. , Farge Y.
Published: February 2003

The use of synchrotron radiation is shown to give promising properties to x-ray absorption microanalysis. Geological samples, 30 μm thick, have been analyzed over large areas with a few micrometers resolution, and maps of transition-metal distributions were obtained in less than 15 min. An increased resolution is expected with x-ray resists.
An inverse ac Josephson effect voltage standard
Authors: Levinsen M. T. , Chiao R. Y. , Feldman M. J. , Tucker B. A.
Published: February 2003

An unbiased Josephson tunnel junction, irradiated with microwaves, can spontaneously develop quantized dc voltages. We explain this effect with reference to the shunted junction model and to analog experiments. This effect may be utilized to significantly improve both the accuracy and the simplicity of the Josephson voltage standard.
The role of E/p in waveguide CO2 TE lasers
Authors: Smith P. W. , Maloney P. J. , Wood II O. R.
Published: February 2003

The role of the electric field to pressure ratio (E/p) in waveguide CO2 TE lasers is shown to be different from that in conventional CO2 TE lasers. For waveguide CO2 TE lasers, the optimum E/p in the positive column is greater than that which produces the most efficient excitation of CO2 vibrational levels, because of the necessity to reduce the detrimental effects of the power dissipated in the cathode fall region of the discharge. Experimental results on small-signal gain versus input energy as a function of E/p are shown to be in agreement with theory. Implications for device design are discussed.
Efficient power combiner for multiplexing multiple sources to single-fiber optical systems
Authors: Hill K. O. , Kawasaki B. S. , Johnson D. C.
Published: February 2003

Efficient combining of optical power from three input optical fibers to a single trunk fiber is demonstrated using fibers of different core/cladding diameters in a biconical taper configuration. The combiners have insertion loss less than 1 dB and optical isolation greater than −50 dB.
A simple technique for suppressing Li2O out-diffusion in Ti : LiNbO3 optical waveguide
Authors: Miyazawa Shintaro , Guglielmi R. , Carenco A.
Published: February 2003

Li2O out-diffusion in Ti-diffused LiNbO3 optical waveguide was suppressed by annealing a LiNbO3 y-cut substrate in Li2CO3 powder prior to the Ti-diffusion process. The waveguide, made of the substrate annealed at 600 °C for 72 h, supported single TE and TM modes without any out-diffusion modes for 0.6328-μm light propagation.
Chemical generation of a population inversion between the spin-orbit states of atomic iodine
Authors: Pritt A. T. , Coombe R. D. , Pilipovich D. , Wagner R. I. , Benard D. , Dymek C.
Published: February 2003

When I2 is injected into a stream of chemically produced O*2(1Δg), electronically excited iodine atoms [I* (52P1/2)] are created. For suitably high O*2/O2 ratios, a population inversion is established between the 52P1/2 and 52P3/2 atomic states of iodine. The inversion was observed using an optical double-resonance technique.
cw and improved pulsed operation of the 14- and 16-μm CO2 lasers
Authors: Wexler B. L. , Manuccia T. J. , Waynant R. W.
Published: February 2003

The performance of the 14- and 16-μm CO2 lasers produced in the electric discharge gasdynamic laser has been significantly improved by the addition of a small percentage of H2 to deactivate the (0110) level. This addition tripled the pulsed output of the laser, and 45 μJ at 14 μm and 25 μJ at 16 μm were observed. cw oscillation was achieved for the first time, with output powers of 0.6 and 0.9 W, respectively. The effect of collisional processes in limiting the CO2 density is discussed.
Discharge-related limitations of CO2 optical gain in TE channel waveguides
Authors: Papayoanou A.
Published: February 2003

Investigation of TE discharges in a 1.6-mm square channel has revealed reasons for the inefficient operation of such devices as CO2 oscillators. At high repetition rates the pulsed glow discharges are not wall confined above 100 Torr. Thus wall cooling and complete volumetric excitation are reduced. Energy deposited into the cathode fall region creates considerable problems. At low pressures this energy is a large fraction of the total discharge energy, whereas for higher pressures the power and power density deposited in this region is very high. The resultant localized gas heating dissociates molecules, creates turbulence, and limits gain.
Low-velocity stopping of heavy ions
Authors: Nesbet R. K. , Ziegler J. F.
Published: February 2003

The apparent discrepancy between theory and experiment in low-velocity electronic stopping of heavy ions is shown to be resolved for several representative cases by taking into account the velocity dependence of both the effective charge of the ions and of the atomic stopping power for fixed ionic charge. A new formula for the electron density dependence of the stopping number is introduced, based on recent work by Vager and Gemmell.
Phase imaging in reflection with the acoustic microscope
Authors: Atalar A. , Quate C. F. , Wickramasinghe H. K.
Published: February 2003

When a polished surface of a single crystal is examined with a converging acoustic beam the reflected signal has a characteristic response that is dependent upon the elastic properties of the reflecting surface. This property can be used in the acoustic microscope to monitor the thickness of layers deposited on these surfaces and the small-scale variations of the elastic parameters in these materials.
Light detection in dielectric waveguides by a photodiode through direct evanescent field coupling
Authors: Ranganath T. R. , Wang Shyh
Published: February 2003

Though LiNbO3 and LiTaO3 have excellent electro-optic properties, they are insulators and therefore do not lend themselves for the realization of an efficient photodetector scheme. Using the idea of evanescent coupling we propose and demonstrate a convenient and efficient light detection scheme to be used with a variety of dielectric waveguide devices. The scheme utilizes an etched mesa photodiode fabricated in silicon, evanescently coupled to a waveguide for light detection. The high detection sensitivity (0.3 mA/mW at λ=6328 Å) and the possibility of incorporating integrated circuits on a common substrate (in Si or GaAs) make the scheme very attractive for hybrid integration of thin-film optical and electronic devices.
Nonlinear refractive index of fluoride crystals
Authors: Milam D. , Weber M. J. , Glass A. J.
Published: February 2003

Nonlinear refractive-index coefficients of 11 fluoride crystals were measured at 1064 nm using time-resolved interferometry. A simple empirical expression is given for the index nonlinearity in terms of the d-line refractive index and Abbé number which agrees with measured values for both fluoride crystals and optical glasses and which can be used to estimate index nonlinearities. Since the nonlinear indices of several fluoride crystals are among the smallest reported for solids, these materials are of interest for transmitting optical components in high-power laser systems where self-focusing is important.
Harmonic generation in Nd : laser-produced plasmas
Authors: McLean E. A. , Stamper J. A. , Ripin B. H. , Grie H. R. , McMahon F J. M. , Bodner S. E.
Published: February 2003

The fundamental and second through the fifth harmonic spectral lines have been observed from the plasma produced when a 75-psec Nd : glass laser (∼1016 W/cm2) is focused onto a thick planar polystyrene target. Both line profiles and relative intensities of these harmonic are given.
Velocity saturation and the conduction-band structure of Ga1−xAlxAs under pressure
Authors: Sugeta T. , Majerfeld A. , Saxena A. K. , Robson P. N.
Published: February 2003

The high-field current-field characteristics of Ga1−xAlxAs transferred-electron-effect devices for 0.2<x<0.4 have been measured under hydrostatic pressure, as well as the pressure dependence of the Hall coefficient in the range 0–15 kbar. From the critical pressure to suppress current instabilities and the Hall-coefficient data, the energy positions of the L and X conduction-band minima are derived for 0<x<0.45. The Γ-L and Γ-X energy separations for GaAs are determined to be 0.29±0.01 and 0.485 eV, respectively. The Γ-X and Γ-L crossover points are x=0.43 and 0.45±0.02, respectively. The alloy composition for velocity saturation is x=0.33, and the corresponding threshold field, as determined from a probe measurement, is 6.5±0.5 kV/cm.
New evidence on the quantum efficiency of Nd : YAG
Authors: Kennedy C. J. , Barry J. D.
Published: February 2003

We have observed that the thermal loading in a pumped Nd : YAG laser rod is reduced by the action of stimulated emission. Preliminary results allow us to deduce that the quantum efficiency of the 4F3/2 upper laser level is 0.63±0.10.
Low-loss optical transmission through bent hollow metal waveguides
Authors: Garmire E. , McMahon T. , Bass M.
Published: February 2003

The transmission of 10.6-μm light in bent metal-walled waveguides of rectangular cross section is described both theoretically and experimentally. It is shown that the bending loss per angle of bend in these waveguides is explicitly independent of waveguide height, bend radius, and light wavelength, depending only on the reflectivity of the waveguide walls. In confirming experiments, guides with aluminum walls showed 95% transmission per radian of bend for radii in the range from less than 1 cm to 1 m.
Generation of step tunable coherent radiation in the XUV by fifth-order frequency mixing
Authors: She C. Y. , Reintjes J.
Published: February 2003

The generation of coherent radiation at four new frequencies (59.1, 62.6, 71.0, and 76.0 nm) in the XUV by fifth-order frequency mixing of harmonics from a Nd : YAG laser is reported. The relative strength of the fifth-order mixing processes in He and Ne is discussed. Comparison of fifth and third harmonic generation in He shows higher conversion to the fifth harmonic for sufficiently tight focusing.
Efficient up-conversion of 10.6-μm radiation into the green spectral range
Authors: Jantz W. , Koidl P.
Published: February 2003

Conversion of 10.6-μm laser radiation into the spectral region of almost optimal photomultiplier performance is realized by nonlinear mixing of the infrared signal with a dye laser. Quantum conversion efficiencies exceeding 40% are obtained. This order-of-magnitude improvement of the up-converter efficiency was achieved with a AgGaS2 crystal of only 5 mm length, because the noncritical collinear 90° type-I phase-matching geometry was realized.
Bubble motion at small drive fields
Authors: Barbara B. , Magnin J. , Jouve H.
Published: February 2003

Bubble translations carried out at small drive fields show a dependence of the minimum gradient amplitude needed for a motion as a function of its duration. The phenomenon can be described in terms of an activated process, with an activation energy inversely proportional to the gradient field. This law is interpreted by using a model where the motion is accomplished through bubble surface variations.
Fiber-optical interferometer
Authors: Simon A. , Ulrich R.
Published: February 2003

A rectangular optical waveguide of homogeneous refractive index (dimensions 0.10×0.14×100 mm3) is designed to provide double self-imaging of either end face upon the opposite one. We show how to use this guide as a fiber-optical beamsplitter and, with the addition of a mirror, as a two-beam interferometer. The operation of the interferometer demonstrates the mutual coherence of the split images. Applications are possible for in-line fiber-optical interferometric devices.
Self-induced transparency in HF gas using an HF chemical laser
Authors: Peterson Lauren M.
Published: February 2003

Self-induced transparency (SIT) of HF laser radiation at λ 2.7 μm has been observed in low-pressure HF gas for several P1(J) transitions. Low-loss propagation through the resonantly absorbing medium was observed, and intensity threshold values for the onset of SIT were found to agree with those predicted by theory. Laser pulses of high peak power and/or long duration were found to break up into several individual 2π pulses. The resulting frequency of modulation in the output waveform was in quantitative agreement with theory and the damping of the modulation envelope was in agreement with the rotational relaxation time of the HF transition. Measurements showed that the velocity of propagation of the laser pulse through the HF gas at millitorr pressures was as little as 1/40 the speed of light in vacuum.
Tunable DFB laser with fan-shaped grating
Authors: Matsuda A. , Iizima S.
Published: February 2003

Fan-shaped grating whose period is continuously varied from 1950 to 2020 Å has been fabricated on the glass substrate by the holographic technique using photoresist and twisted mirrors and subsequent reactive sputter etching. A N2 laser pumped thin-film dye laser has been constructed with dye-doped polyurethane film coated on the glass substrate which has the fan-shaped-grating corrugation on its surface. It has been able to generate the laser light of the wavelength ranging from 5861 to 6071 Å.
Infrared response of lightly doped Schottky diodes
Authors: Champlin Keith S. , Eisenstein Gadi
Published: February 2003

The traditional hf model of a Schottky diode has been extended to include skin effect, carrier inertia, and displacement current. Above the plasma frequency, results differ considerably from those of the traditional model. The extended model helps understand recently reported detection of 10.6-μ radiation with Ge diodes doped to only 1016 cm−3.
Effects of small misalignments in empty unstable resonators
Authors: Perkins J. F. , Cason Charles
Published: February 2003

Effects of misalignment of rectangular-cross-section unstable resonators are investigated by calculations of eigenvalues and shapes of transverse modes of empty strip resonators. Small misalignments can substantially affect mode-loss separation. A design criterion is suggested for choice of Fresnel numbers such that effects of misalignments are minimized.
Optical multiplexer for multimode fiber transmission systems
Authors: Tomlinson W. J. , Aumiller G. D.
Published: February 2003

We have constructed and tested an optical multiplexer for use with multimode optical fibers. The device utilized a blazed plane reflection grating with a single GRIN-rod lens, and was made from commercially available components. The wavelength spacing of the two channels was 27 nm, the insertion losses were ⩽2.4 dB, and the crosstalk was <−30 dB. Optimized versions of the device should be capable of providing at least four channels, with still lower insertion losses, in a rugged stable package 1–2 cm long by 2–4 mm in diameter.
Harmonic generation in CO2 laser target interaction
Authors: Burnett N. H. , Baldis H. A. , Richardson M. C. , Enright G. D.
Published: February 2003

We report the observation of an extended series of integral harmonic lines in the spectrum of direct backscatter of 10.6-μm radiation incident at intensities ≳1014 W/cm2 onto planar solid targets. We have observed and spectrally resolved up to the eleventh harmonic (0.95 μm) at intensities well above the plasma continuum background.
A method for finding critical stresses of dislocation movement
Authors: Hu S. M.
Published: February 2003

A method is presented which makes possible the determination of the critical resolved shear stress, τc, for dislocation movement in a crystal. The method is based on the analysis of dislocation rosettes which are generated either by microindentation, or by precipitates of a second phase. The method does not require a knowledge of the indentation (or precipitate) stress field; it requires only information on the positions of a set of leading dislocation loops. At once one can also obtain the effective indentation stress field and, for the first time, the precipitate stress field. For illustration, the method is applied to the determination of τc in silicon, using both indentation and precipitate dislocation rosettes. The value of τc thus obtained varies from a low of 3×107 dyn/cm2 in oxygen-free samples to a high of 5.5×108 dyn/cm2 in a sample containing ∼2×1018 atoms/cm3 of oxygen with clustering. The SiO2 precipitate stress field in the present case was found to vary as x−1, suggesting that the precipitate is probably a thin plate.
EPR of a thermally induced defect in silicon
Authors: Lee Y. H. , Kleinhenz R. L. , Corbett J. W.
Published: February 2003

Two EPR spectra are resolved in quenched silicon; one is attributed to a surface damage formed during the quench and the other to the interstitial iron (Fe0) previously identified by Woodbury and Ludwig in Fe-diffused silicon. The enthalpy and entropy for the Fe0 formation are determined to be 2.39 (±0.03) eV and 3.3 (±0.3) K, respectively. The migration energy of Fe0 is 0.69 (±0.03) eV. The transition-metal ion is present in as-grown silicon and moves to the Td interstitial site upon heat treatment.
An interdigital transducer for acoustic imaging
Authors: Toda Kohji , Murata Yoichi
Published: February 2003

We have devised a simple acoustic focusing device with an interdigital transducer in which all radiation from each section of the transducer constructively interferes at a focal point in water. The device is applicable to the acoustic imaging in both transmitting and reflecting modes.
Surface acoustic waveguides on LiNbO3 formed by titanium in-diffusion
Authors: Weller J. F. , Crowley J. D. , Giallorenzi T. G.
Published: February 2003

For the first time a surface acoustic waveguide has been made by diffusing titanium into yz-LiNbO3 to serve as the fast cladding region. The guides are excited by transducers operating at 240 MHz and exhibit low loss. Dispersion characteristics presented illustrate the effects of lateral confinement.
CO2 laser-produced ripple patterns on NixP1−x surfaces
Authors: Isenor N. R.
Published: February 2003

When CO2-laser pulses of ∼50 ns duration and intensity of ∼100–500 MW/cm2 are incident upon NixP1−x surfaces in oxygen-containing atmospheres, distinctive ’’ripple’’ patterns are etched into the surfaces. The ripple wave fronts are normal to the E field and vary in spacing from ∼λlaser at normal incidence to ∼0.5λlaser for π polarization at grazing incidence.
Vacuum ultraviolet lasing from highly ionized noble gases
Authors: Marling Jack B. , Lang Daniel B.
Published: February 2003

Vacuum ultraviolet laser emission was obtained from highly ionized noble gases using a simple longitudinal discharge device. Electric discharge excitation pulses with 500 ns duration and peak current density up to 14 000 A/cm2 produced lasing on five argon and krypton ion transitions below 200 nm. The two strongest emissions exhibited 0.1–1 kW peak power from Kr IV at 195.027 nm and 175.641 nm.
Spectral phase-matching properties for second harmonic generation in nonlinear crystals
Authors: Liu Yung S.
Published: February 2003

The spectral phase-matching bandwidths in LiIO3, LiNbO3, CDA, and KDP (type I and type II) for second harmonic generation (SHG) at 1.06 μm have been accurately measured using a tunable line-narrowed Nd : glass laser. The present results disagree with previously published data. Mechanisms such as sum-frequency generation which could contribute to the discrepancy are discussed and demonstrated in a 90° phase-matched deuterated CDA crystal.
Electrically active optical bifurcation: BOA
Authors: Papuchon M. , Roy Am. , Ostrowsky D. B.
Published: February 2003

We report the realization of an electro-optical switch based on the interference between modes in a two-mode waveguide (equivalent to a directional coupler with no gap between the guides). Switching is achieved by uniformly changing the refractive index of the guide. This permits attaining the two switching states even in the presence of fabrication errors, with a very simple electrode configuration. Crosstalks of −16 and −18 dB for command voltages of 8 and −18 V have been obtained for such a structure realized in Ti : diffused lithium niobate.
P
+/N high-efficiency silicon solar cells
Authors: Bae M. S. , D’Aiello R. V.
Published: February 2003

A novel boron-diffusion process is described for the fabrication of high-efficiency P+/N silicon solar cells. Over the range of diffusion parameters investigated this diffusion process results in a boron-rich surface layer and shallow junctions (0.15–0.4 μm) having two properties important to the formation of high-efficiency solar cells—relatively low values of sheet resistance (35–140 Ω/⧠) which facilitates the front-surface grid-metal design and large resultant lifetimes approaching 60 μs. The characteristics of P+/N solar cells, fabricated using this diffusion process in single-crystal (CZ) silicon wafers, having AM1 efficiencies ranging from 14 to 17% are presented.
The equivalent gap alteration by the scattering caused by acoustic domains in CdS
Authors: Hata Tomonobu , Iwahashi Humio , Washioka Hiroyuki , Hada Toshio
Published: February 2003

An acoustic domain in CdS crystals scatters a radiated optical beam near the intrinsic absorption edge. This paper presents work showing that the equivalent band-gap alteration caused by the scattering effect is observed in 600–1000-μm-thick samples. This alteration is caused by the following: (i) In the CdS crystal the optical transmission of incident light with e∥c is larger than that for incident light with e⊥c (e: polarization of the incident light; c: c axis of the crystal). (ii) When the incident light is scattered by the shear acoustic wave in the sample, the plane of polarization is rotated by 90°. Therefore, the incident light with e⊥c behaves as if it were e∥c and the optical transmission increases.
Visualization of solid material joints using a transmission-type scanning acoustic microscope
Authors: Tsai C. S. , Wang S. K. , Lee C. C.
Published: February 2003

The results of imaging experiments for the interfacial regions of four representative solid material joint, composite, and bonds, using a transmission-type scanning acoustic microscope operating at 150 MHz, are reported. These are (1) Mylar-epoxy-Mylar joint, (2) brass-copper grid-adhesive-brass composite, (3) brass-solder-brass bond, and (4) silicon-solder-copper bond. Flaws, voids, and defects in these specimens have been detected.
Noise properties of a He-Se laser
Authors: Suzuki Takeo , Ieiri Shogo
Published: February 2003

Noise properties of a He-Se laser were investigated. A dispersion relation of fluctuations of side light along the positive column was obtained by using a real-time digital correlator with bandpass filters. Interpretation of the dispersion relation suggests that the cause of the noise is not just the metal-vapor density fluctuations, but also the randomlike moving striations.
Two-dimensional observation of Gunn domains at 1 GHz by picosecond pulse stroboscopic SEM
Authors: Hosokawa T. , Fujioka H. , Ura K.
Published: February 2003

The high-field domains in a Gunn-effect diode triggered at 1 GHz have been studied pictorially with the stroboscopic scanning electron microscope. Y-modulated images have also been obtained.
Capacitively shunted variable-thickness microbridges
Authors: Yeh J. T. C. , Buhrman R. A.
Published: February 2003

A study has been made of capacitively shunted Pb variable-thickness microbridges. The observed hysteretic I-V characteristics of these microbridges are in at least qualitative agreement with the predictions of the shunted junction model. Discrepancies between the model and experiment are attributed, in part, to the inductance of the microbridge and capacitor films. In some cases, a voltage-switching structure is also observed, which is due to geometrical resonances in the thin-film structure.
Thermal transient analysis of pulsed heat deposition in sheet targets and observations of plasma spreading
Authors: McKay J. A. , Schriempf J. T.
Published: February 2003

The decay of temperature transients in pulse-heated sheet targets can be analyzed to deduce the initial magnitude and spatial distribution of target heating. We present formulas describing such thermal transients, and give an example of analysis involving heating of aluminum by a pulsed CO2 laser with air plasma ignition. Plasma spreading of heat deposition over an area much larger than the laser beam cross section is shown.
Diffusion coefficients of Tl+ ions in ion-exchanged glass
Authors: Kobayashi Keiji
Published: February 2003

Diffusion of Tl+ ions was determined in a multicomponent glass by means of an ion-exchange technique. Diffusion coefficients of Tl+ ions of 9.86×10—7 to 4.34×10−10 cm2/sec were calculated for glass which was immersed at 450 °C for 24 h in TlNO3-KNO3 molten salts with the composition Tl/(Tl+K) =0.1 to 0.5.
Cd II excitation in slow He+-Cd and He+2-Cd collisions
Authors: Ranjbar F. , Harris H. H. , Leventhal J. J.
Published: February 2003

Cross sections for production of excited states of Cd II resulting from He+-Cd and He+2-Cd collisions are reported. These data suggest that high-pressure (∼ atmospheres) operation of a He-Cd laser in which pumping is achieved by charge-transfer excitation with reactant He+2 might be possible. Selective population of the (4d)9(5s)2 2D3/2 level in He+2-Cd collisions produces enhancement of the 325.0-nm line relative to the 441.6 nm.
A direct nuclear pumped 1.45-μ atomic carbon laser in mixtures of He-CO and He-CO2
Authors: Prelas M. A. , Akerman M. A. , Boody F. P. , Miley G. H.
Published: February 2003

Direct nuclear pumping of the 1.45-μ line in neutral carbon has been achieved using the 10B(n,α)7Li reaction. Lasing was observed in mixtures of both He-CO and He-CO2. The laser has the lowest neutron flux threshold to date, ∼4×1014 n/cm2 sec, and a 20-msec lasing time. Lasing occurred at pressures from 20–800 Torr He with partial pressures of CO and CO2 from ∼1–21 mTorr. A delay, increasing to ∼5 msec for lower total pressures, was observed between the peak of the neutron pulse and the peak of the laser signal for mTorr partial pressures of CO2, and for mTorr partial pressures of N2-CO mixtures.
A tunable stabilized single-mode TEA CO2 laser
Authors: Nicholson J. P. , Lipton K. S.
Published: February 2003

A TEA CO2 laser which can be operated in a single mode is described. The laser can be tuned to most rotational lines in the 9.6-μ and 10.6-μ CO2 emission bands. The system can also be fine-tuned to oscillate up to ±2 GHz off any particular line center. Application of the laser to obtain high-resolution spectroscopy of a D2O absorption line is briefly described.
310-MHz SAW resonator with Q at the material limit
Authors: Li R. C. M.
Published: February 2003

Two-port SAW resonators have been made on ST-cut quartz to operate at 310 MHz with unloaded Q values in vacuum in excess of 32 000 (the limit on Q imposed by intrinsic material loss at this frequency is approximately 33 000). Design principles and fabrication techniques employed in the realization of these devices are described.
Effects of anisotropy on SAW resonator transverse modes
Authors: Coldren L. A.
Published: February 2003

A quantitative comparison of anisotropic theory with experiments on SiO2 and LiNbO3 shows the strong effects of wave surface anisotropy on SAW resonator transverse modes. Simple approximate formulas for the frequency splittings of the resonant modes are given for both the waveguided case and the unguided case where ’’free-space’’ modes are prevalent.
Ion-implanted n- and p-type layers in InP
Authors: Donnelly J. P. , Hurwitz C. E.
Published: February 2003

InP has been doped by implantation with several different ions to yield layers of both n- and p-type conductivity. Se+ and Si+ were found to be efficient n-type dopants with activations in excess of 75% for moderate doses (1×1014 cm−2 at 400 keV). At doses of 1×1015 cm−2, sheet resistivities as low as 15 Ω/⧠ were obtained. Cd+, Mg+, and Be+ were all acceptors, with Mg+ yielding a sheet hole concentration as high as 5×1013 cm−2 for a dose of 1×1014 cm−2 at 150 keV. Reproducible annealing of implanted samples at temperatures up to 750 °C was accomplished with a pyrolytic phosphosilicate glass (PSG) encapsulation. Implants of Kr+ indicate that residual implantation damage is n type.
Structural changes in amorphous Pd80Si20 by neutron irradiation
Authors: Doi Kenji , Kayano Hideo , Masumoto Tsuyoshi
Published: February 2003

Amorphous Pd80Si20 was irradiated with fast neutrons (≳1 MeV) to a fluence of 5×1020 neutrons/cm2. X-ray scattering intensities were measured before and after the irradiation with monochromatic Cu-Kα1 rays. Scattered intensities for s≳0.4 Å−1 (s=2 sinϑ/λ) proved unaffected, while intensities were found remarkably enhanced for s<0.4 Å−1 after the irradiation, i.e., in the small-angle region and the leading edge of the first halo. The results are discussed in relation to the structural anomalies in amorphous solids.
Laser-induced absorption line narrowing for ions in crystals: Application to the hyperfine structure of the 6011-Å Pr3+ : LaCl3 line
Authors: Delsart C. , Pelletier-Allard N. , Pelletier R.
Published: February 2003

We report on the observation of absorption line narrowing in a crystal. A saturating cw single-mode dye laser leads to hole burning over a homogeneous width according to the site selection, while a second tunable cw single-mode dye laser probes the perturbed profile. Two-level and three-level resonances corresponding to the Pr3+ : LaCl3 6011-Å line hyperfine structure are obtained with very high spectral resolution (σ/Δσ≃6×107).
Photoluminescence of hydrogenated amorphous silicon
Authors: Pankove J. I. , Carlson D. E.
Published: February 2003

Amorphous silicon obtained by the glow-discharge decomposition of silane can contain on the order of 18–50 at.% of hydrogen. Heating this material above 350 °C causes the evolution of H2. The photoluminescence efficiency decreases with increasing hydrogen depletion.
Origin of n≃2 injection current in AlxGa1−xAs heterojunctions
Authors: Henry C. H. , Logan R. A. , Merritt F. R.
Published: February 2003

We show that the n≃2 current in AlxGa1−xAs heterojunctions is due to surface recombination. The rate of recombination at etched surfaces is evaluated in two photoluminescence experiments. Both of these experiments provide evidence that the rate of surface recombination is proportional to exp(eV/2kT) and has the correct magnitude to account for the measured I-V curves. The n≃2 behavior is shown to be a necessary consequence of maintaining equality between surface and depletion layer charge.
Enhancement of diffusion length in EFG ribbon solar cells under illumination
Authors: Ho C. T. , Bell R. O. , Wald F. V.
Published: February 2003

The short-circuit current, efficiency, and minority-carrier diffusion length of EFG ribbon silicon solar cells have been measured as a function of illumination level between 0 and 5 suns and found to increase. The faster rate of increase of the current in ribbon cells compared to CZ we attribute to the enhancement of the minority-carrier diffusion length under illumination. A quasicontinuous deep-trap model with a Gaussian distribution of compensated donor states is proposed to account for these observations.
Room-temperature operation of Ga(1−x)AlxAs/GaAs double-heterostructure lasers grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D.
Published: February 2003

Room-temperature pulsed laser operation of Ga(1−x)AlxAs/GaAs double-heterostructure lasers grown by metalorganic chemical vapor deposition (MO-CVD) has been achieved. Threshold current densities as low as 1.2 kA/cm2 have been attained in totally internally reflecting devices. In broad-area Fabry-Perot diodes, threshold current densities as low as 3 kA/cm2 have been attained. These lasers are fabricated from five-layer epitaxial structures grown entirely by the MO-CVD process.
Depth distribution of knock-on nitrogen in Si by phosphorus implantation through Si3N4 films
Authors: Hirao T. , Inoue K. , Takayanagi S. , Yaegashi Y.
Published: February 2003

The concentration profiles of phosphorus and knock-on nitrogen in silicon after phosphorous implantations into Si3N4-Si systems have been investigated by using secondary ion mass spectrometry (SIMS). The tails were found on the phosphorus distribution in silicon after the implantation through Si3N4 films. The concentration profiles of knock-on nitrogen in silicon have been determined by measuring both the in-depth profiles of knock-on nitrogen and those of nitrogen after additional nitrogen implantation into a bare silicon embedded with knock-on nitrogen. The concentration profiles of knock-on nitrogen show a very high concentration near the surface and extending tails. It was found that the tails were observed at the deeper portion in silicon as energy increased, for a given Si3N4 layer.
Decay time measurement of the luminescence of CuCl excited by a picosecond laser
Authors: Ostertag E. , Grun J. B.
Published: February 2003

The luminescence of CuCl excited by a mode-locked Nd3+ : YAG laser is studied at liquid-helium temperature. It is recorded through an optical Kerr cell, used as a sampling gate, by an optical multichannel analyzer synchronized to the mode-locked laser. At the excitation intensity used, athe luminescence of CuCl is essentially due to the radiative decay of biexcitons. The decay of this luminescence contains two components, a fast one (τ≃95 ps) followed by a slower one (τ≃450 ps).
The influence of diluent gas on the XeF laser
Authors: Champagne L. F. , Harris N. W.
Published: February 2003

Substitution of neon for argon as the diluent gas in electron-beam-pumped XeF lasers allows increased optical extraction energies of 2.8 J l−1 and efficiencies of 1.8%. The improved performance in neon diluent is due to a reduction of the optical absorption in the laser medium which occurs at the laser wavelength. This optical absorption is shown to be present when the rare gases along are irradiated.
Optical rotatory power near a cholesteric–smectic-A transition
Authors: Sokol Paul E. , Ho John T.
Published: February 2003

A sensitive temperature dependence of the optical rotatory power of a cholesteric liquid-crystal film in the vicinity of the smectic-A phase is reported. The results are consistent with the pretransitional unwinding of the helical structure. The use of the effect in thermometry is discussed.
X-ray emission characteristics of plasmas created by a high-intensity CO2 laser
Authors: Enright G. D. , Burnett N. H. , Richardson M. C.
Published: February 2003

The spectrum of the x-ray continuum and line emission emanating from Al, Mg, and (CH2)n plasmas created with a nanosecond CO2 laser pulse has been investigated at irradiance levels up to 2×1014 W/cm2.
Far-infrared photoconductivity of uniaxially stressed germanium
Authors: Kazanskii A. G. , Richards P. L. , Haller E. E.
Published: February 2003

The influence of uniaxial stress on the extrinsic photoconductivity of gallium-doped germanium has been investigated. It has been found that the long-wavelength cutoff is shifted from 114 μm for zero stress to 200 μm for a uniaxial stress of 6.6×103 kg/cm2 along a [100] direction. At this value of stress the responsivity was ∼2×104 V/W and the NEP was ∼2×10−11 W/Hz1/2 at 190 μm.
Drift mobilities of Na+ and K+ ions in SiO2 films
Authors: Stagg J. P.
Published: February 2003

Na+ and K+ ion mobilities in thermally grown SiO2 films have been determined from transient ion curret measurements in MOS capacitors. The mobilities were determined from the observed transit times of Na+ and K+ ions measured in the temperature ranges 40–180 °C and 230–300 °C, respectively. For Na+ ions in both a dry-grown oxide and one grown in a 10% HCl/oxygen mixture, μ=1.0 exp(−0.66 eV/kT) cm2/V sec. For K+ ions in a dry-grown oxide, μ=0.03 exp(−1.09 eV/kT) cm2/V sec.
The electronic and nuclear stopping of energetic ions
Authors: Ziegler J. F.
Published: February 2003

The electronic contribution to stopping of 127 ion-target combinations is calculated by the use of an expression for scaling from proton stopping powers. The scaling is found to be accurate, with a standard error of 4.5% relative to experimental measurements. Also, an evaluation is made of a recently proposed nuclear stopping formalism and evidence is found that it is more accurate than LSS nuclear stopping.
Composition-tuned PbSxSe1−x Schottky-barrier infrared detectors
Authors: Schoolar R. B. , Jensen J. D. , Black G. M.
Published: February 2003

Schottky-barrier photodiodes were prepared by depositing either lead or indium onto p-type PbSxSe1−x epitaxial films. These photodiodes had 77 °K zero-bias resistance-area products of 26–21 000 Ω cm2 as x varied from 0 to 1, respectively. The peak detectivities were close to the background limit and could be composition tuned between 3.7 and 6.9 μm at 77 °K. Narrowband detectors were prepared by using one film as a short-wavelength cutoff filter and a second film, of slightly different composition, as the detector. These devices exhibit high quantum efficiencies, low half-bandwidths, and insensitivity to variations in incident angle.
Resonant enhancement of the magnetic radiative force
Authors: Stamper J. A.
Published: February 2003

Earlier work described a polarization-dependent radiation force for laser radiation interacting with a magnetized plasma. A new derivation, based on the upper-hybrid mode, shows that this force has a resonant enhancement and implies its relation to a magnetic type of resonant absorption.
Conjugate wave-front generation and image reconstruction by four-wave mixing
Authors: Bloom D. M. , Bjorklund G. C.
Published: February 2003

Operation of a new nonlinear backward-wave optical device which produces the conjugate of an arbitrary incident wave front is demonstrated. Good-quality reconstructed images are obtained through a phase distorting media.
Liquid-phase-epitaxial growth of lattice-matched In0.53Ga0.47As on (100) -oriented InP
Authors: Hyder S. B. , Antypas G. A. , Escher J. S. , Gregory P. E.
Published: February 2003

Growth of InGaAs lattice matched to InP was achieved for the first time on the (100) orientation of InP by liquid-phase epitaxy. Growth conditions and melt composition for such a growth are presented. In0.53Ga0.47As/InP and InP/In0.53Ga0.47As/InP heterojunction structures for 1.7-μm field-assisted photocathodes have also been fabricated on (100) InP substrates.
Space-charge effects in long coaxial vacuum transmission lines
Authors: Poukey J. W. , Bergeron K. D.
Published: February 2003

A new two−dimensional time-dependent electromagnetic particle code is applied to the high-voltage pulsed power flow problem in a long self-magnetically insulated coaxial line. It is found that the current leakage occurs only near the front of the voltage pulse, that energy transport is very efficient at high voltages, and that the electrons in the insulated region do not get close to the anode.
Spinodal decomposition in amorphous Au-implanted Pt
Authors: Singhal S. P. , Herman H. , Hirvonen J. K.
Published: February 2003

High-energy high-dose Au implantations into Pt have produced an amorphous structure, as observed by transmission electron microscopy. A modulated microstructure has apparently been concurrently formed, and this is concluded to be spinodal decomposition. This result is consistent with independent small-angle neutron-scattering experiments.
Stimulated emission and optical gain in HgI2
Authors: Catalano I. M. , Cingolani A. , Ferrara M. , Lugarà M. , Minafra A.
Published: February 2003

Stimulated emission in HgI2 at 80 °K due to an exciton-electron collision cooperative process is reported. The line shape of the stimulated emission band depends on the excitation wavelength. High optical gain has been measured. These effects are observed both with one- and two-photon pumping.
The regrowth of amorphous layers created by high-dose antimony implantation in 〈100〉 silicon
Authors: Tamminga Y. , Josquin W. J. M. J.
Published: February 2003

The epitaxial regrowth of amorphous silicon layers created by a high-dose antimony implantation in silicon was found to be influenced by the presence of antimony atoms. At concentrations of less than 1020/cm3 the regrowth rate was enhanced in comparison with undoped amorphous silicon layers. For higher antimony concentrations, however, this regrowth was retarded, while for concentrations of about 5×1021/cm3 it was completely inhibited. The concentration limit above which the influence on the regrowth rate is negative appears to be an order of magnitude larger than the maximum solid solubility of the impurity atoms.
Oscillator and superradiant 66 μ emission from a ’’zigzag’’ pumped high-energy D2O laser
Authors: Dodel G. , Magyar G.
Published: February 2003

A zigzag quasilongitudinally (ϑ=15°) CO2 laser-pumped D2O oscillator at 66 μ is described. Maximum energy was 42 mJ in a 2.5-μs pulse, representing ∼9% quantum conversion efficiency. The spectrum was only a few axial modes wide. With a single-pass mirrorless arrangement, a strong superradiant signal was observed, spatially following the CO2 beam at 15° to the axis and easily distinguishable from a weak axial emission.
High-average-power Raman oscillator employing a shared-resonator configuration
Authors: Ammann E. O.
Published: February 2003

The performance of a high-repetition-rate (kHz) Raman oscillator is described. The oscillator employs a new configuration in which the Raman medium is located inside the pumping laser, and the Stokes outputs and pumping laser share the same resonator. The Raman oscillator consists of lithium iodate pumped by the 1.08-μm output of Nd : YAlO3. In separate experiments, we have generated 1.26 W of 1.18-μm first Stokes average output power and 550 mW of 1.31-μm second Stokes average power.
Low-temperature plasma oxidation of GaAs
Authors: Yokoyama N. , Mimura T. , Odani K. , Fukuta M.
Published: February 2003

A low-temperature plasma oxidation of GaAs (lower than 100 °C) has been realized. The oxidation apparatus mainly consists of a quartz tube chamber, a low-power rf oscillator and an electrical magnet. The oxidation rate can be controlled in the range 100–600 Å/min by changing the magnetic field perpendicularly applied to the sample. The interface state density between p-type GaAs and its oxide film is the order of 1010 cm−2 eV−1 around 0.5 eV from the top of the valence band. This low state density suggests that the oxide film can be applied to various GaAs MOS devices. For the oxide film of n-type GaAs, an anomalous frequency dispersion in the MOS capacitance is found in the accumulation region. This anomaly is very similar to that observed in anodic oxidation.
Film-edge-induced stress in silicon substrates
Authors: Hu S. M.
Published: February 2003

Stress fields in silicon substrates, induced by edges of silicon nitride films, were studied by experimentally observing the distribution of indentation-injected dislocation half-loops in the vicinity of the film edge. From this distribution, the stress field was obtained by applying the method of analysis recently introduced by the author. The results were compared to the theoretical stress field due to a line force (an approximation) tangential to the boundary of a half-space, with good agreement.
Stable room-temperature light emission from metal-insulator-metal junctions
Authors: Jain R. K. , Wagner Sigurd , Olson D. H.
Published: February 2003

Stable room-temperature light emission has been observed from planar Mg-MgO-Ag junctions. The light emission is presumably due to roughness-induced radative decay of surface plasma modes excited by tunneling electrons. Roughening of the planar tunnel structure is obtained by growth of a plateletlike structure during slow evaporation of the Mg film.