bluuebunny/crossref_metadata_2025 huggingface dataset:
X-ray topographic observation of moving dislocations in silicon crystals
Authors: Chikawa Jun-ichi , Fujimoto Isao , Abe Takao
Published: January 2004

An instantaneous display of topographic images of individual dislocations was made by the combination of a high-power x-ray generator and a television unit with an x-ray sensing PbO-Vidicon camera tube. Si wafers were deformed by tension (about 300 g/mm2) at about 1000 °C in a vacuum furnace, and, simultaneously, moving dislocations were observed continuously with the television unit. The observation of dislocations moving as fast as 0.3 mm/sec may indicate the possibility that this technique can be a powerful tool in investigating the dynamic properties of dislocations.
Collisional narrowing of infrared water-vapor transitions
Authors: Eng R.S. , Calawa A.R. , Harman T.C. , Kelley P.L. , Javan A.
Published: January 2004

Water-vapor absorption lines in the ν2 band involving transitions between states of high rotational energy have been found to undergo substantial collisional narrowing in the presence of buffer gases. Measurements were carried out near 5.35 μm, using tunable lead sulfide selenide semiconductor diode lasers.
Interdigital electro-optic thin-film modulator
Authors: Polky John N. , Harris Jay H.
Published: January 2004

An integrated optical modulator is presented that achieved 50% depth of modulation. A double-ended coupling prism allowed nitrobenzene to be used as the waveguide material. Also, an approximate theory of operation is developed.
Molecular-beam-stabilized argon laser
Authors: Ryan T.J. , Youmans D.G. , Hackel L.A. , Ezekiel S.
Published: January 2004

The frequency of a 5145-Å argon-ion laser has been locked to an absorption line in a molecular beam of I2. The drift of the laser frequency was less than 20 kHz or Δν/ν<3 × 10−11 for the duration of a run which lasted about 20 min. A molecular-beam external reference is attractive because transitions observed in the isolated conditions in the beam do not suffer shifts due to collisions or collisional broadening and, if the molecular beam is excited orthogonally, Doppler broadening can be virtually eliminated.
Steering acoustic surface waves by nonlinear mixing
Authors: Davis K.L. , Newhouse V.L.
Published: January 2004

We report the generation of difference-frequency acoustic surface waves by the nonlinear interaction of intersecting noncollinear surface-wave beams on [111]-cut bismuth germanium oxide, a material of suitable anisotropy. The wave vector of the mixed-frequency beam can be steered over a range of angles by varying the frequency ratio of the input beams. Agreement with a coupled-mode theory is found. It is pointed out that the effect makes a number of new surface-wave devices possible.
High-power effects in nonlinear optical waveguides
Authors: Zemon S. , Alfano R.R. , Shapiro S.L. , Conwell E.
Published: January 2004

ZnO optical waveguides have been found to withstand power fluxes up to 1011 W/cm2 in pico-second pulses before damage occurred. Under the high power, a TE0 mode at 1.06 μm generated a TM1 mode at 0.53 μm. A ray theory of second-harmonic generation in waveguides has been developed and the experimental results are compared with it.
Determination of deep energy levels in Si by MOS techniques
Authors: Fahrner W. , Goetzberger A.
Published: January 2004

Ions are implanted into a Si–SiO2 interface. If the distribution is several hundred angstroms wide, the ions create interface states at energies corresponding to their bulk levels. With most elements investigated, agreement with previous data is good. Energy levels of the elements Se, Be, Cd, Sn, Ti, Pb, S, C, Ba, Ta, V, Mn, Cs, and Ge were determined by the MOS technique.
High-repetition-rate optical pulse generator using a Fabry-Perot electro-optic modulator
Authors: Kobayashi T. , Sueta T. , Cho Y. , Matsuo Y.
Published: January 2004

A high-repetition-rate optical pulse generator which employs a Fabry-Perot electro-optic modulator as the output coupler of a laser resonator was constructed. Using this generator with a He–Ne 6328-Å laser tube, 21-psec optical pulses at a repetition rate of 2.7 × 109 pps were experimentally obtained with an average power level of 0.5 mW. In addition, it is demonstrated that the width of the pulses obtained from this generator can be narrowed without regard to the gain-linewidth limitation. This kind of pulse generator may be particularly useful for obtaining short optical pulses from low-gain gas lasers, and it is possible to obtain 1010-pps picosecond pulses from a He–Ne 6328-Å laser.
Rotational relaxation and triplet-state effects in the cw dye laser
Authors: Siegman A.E. , Phillion D.W. , Kuizenga D.J.
Published: January 2004

In a cw dye laser apparatus we measure first the fluorescence depolarization in the usual manner, and then the ratio of laser threshold pump powers for the laser polarization parallel and perpendicular to the linearly polarized pump source. From these two measurements we can obtain the important triplet-state parameter KT ≡ kSTτTσT/ σe, as well as the rotational relaxation time for the dye. For Rhodamine 6G in water with Triton X-100, we find KT=0.35 ± 0.02, while with Ammonyx-LO KT=0.25 ± 0.02. These additives also slow down the rotational relaxation of the dye molecule by more than an order of magnitude compared to common organic solvents.
Passive mode locking of the cw dye laser
Authors: Ippen E.P. , Shank C.V. , Dienes A.
Published: January 2004

Passive mode locking of a cw Rhodamine 6G laser is reported. A stable continuous output of picosecond pulses has been achieved. Correlation measurements using second-harmonic generation (SHG) have determined the pulses to be as short as 1.5 psec. The pulses are transform limited and are wavelength tunable over the range 5900–6100 Å.
Background energy level spectroscopy in GaP using thermal release of trapped space charge in Schottky barriers
Authors: Smith B.L.
Published: January 2004

The energy distribution and concentration of electrically active background impurities in GaP have been investigated by observing the current when space charge trapped at these impurities is thermally released within the depletion region of a Schottky barrier formed on the semiconductor. Large-area Schottky barriers are used for these measurements in order that small concentrations of impurities may be detected. The measurements have been carried out for both liquid-encapsulated-Czochralski (LEC)- and liquid-phase-epitaxial (LPE)-grown material using n-type wafers. In LEC GaP, at least seven electrically active background levels are detectable and these exist at concentrations between 1 × 1015−3 × 1016 cm−3, while in LPE GaP only three or four are detectable and these exist in much smaller concentrations of about 1014 cm−3.
Computed secondary-electron and electric field distributions in an electron-beam-controlled gas-discharge laser
Authors: Smith R.C.
Published: January 2004

A Monte Carlo calculation indicates, to first order, the effect of a 4-kV/cm atm sustainer field on the primary-electron dose distribution and the secondary-electron density distribution in an electron-beam-controlled gas-discharge laser. For the 100-keV incident electrons considered, the electron range is, at most, doubled by the field and the maximum lateral displacement increases by 50%. For electrodes separated by 1.1 times the no-field electron range, the secondary electron density has a spatial variation to first order of ± 20%.
Growth of three-dimensional dielectric waveguides for integrated optics by molecular-beam-epitaxy method
Authors: Cho A.Y. , Reinhart F.K.
Published: January 2004

Experimental work was carried out to fabricate three-dimensional waveguides for integrated optics by masking molecular beams during epitaxy of GaAs and AlxGa1−xAs. We report here some preliminary results of this new technique for fabricating dielectric waveguides.
Melting of solids with a linear U
s−u
p relationship
Authors: O'Keeffe David J.
Published: January 2004

A theoretical technique is described for determining the melting line for solids with a linear Us−up (i.e., shock velocity-particle velocity) relationship, utilizing the Lindeman law and an accurate Grüneisen equation of state. A theoretical melting curve for copper is presented, and its good agreement with static high-pressure measurements is noteworthy in view of recent criticism of the Lindemann law.
Quantitative aspects of a soft x-ray laser
Authors: Lax Benjamin , Guenther Arthur H.
Published: January 2004

Calculations show that a soft x-ray laser is feasible when a solid target of low atomic number is excited with a focused mode-locked Nd: glass laser of power level ≳ 1012 W. Quantitative evaluation of the physical processes involved, such as ionization, inversion, stimulated emission, and Auger effect, is presented.
Underwater optical holographic interferometry
Authors: Johnson C.D. , Mayer G.M.
Published: January 2004

Time-average optical holographic interferometry techniques have been used to obtain measurements of an array of sonar transducer elements operating underwater in a 15-m-diam 30-m-deep tank. Holograms were made from outside the tank through a pair of portholes using an argon-ion laser. Measurements were made to provide experimental verification of predicted acoustically induced mutual coupling effects. The quality of the hologram reconstructions was sufficient to resolve fringes spaced 1 mm apart from a viewing distance of 7.5 m.
Internal photoemission in sapphire substrates
Authors: Viswanathan C.R. , Loo R.Y.
Published: January 2004

Electron injection has been accomplished in a thick (10–20 mil) ordered insulator (single-crystal sapphire), using an internal photoemission technique. It is shown that transport properties of electrons in ordered insulators can be easily measured using this technique.
Surface-wave convolution using a CdS-fluid-LiNbO3 structure
Authors: Das P. , Araghi M.N.
Published: January 2004

Experimental results on the convolution of surface waves in a structure of CdS-water-LiNbO3 are reported. The convolved output has been enhanced by applying a dc electric field across CdS having the proper conductivity. The enhancement is large enough to offset the losses involved producing a net electronic gain for the convolution process.
Measurement of the pyroelectric coefficient and permittivity from the pyroelectric response to step radiation signals in ferroelectrics
Authors: Simhony M. , Shaulov A.
Published: January 2004

A method is presented of measuring the pyroelectric coefficient λ and permittivity ε from the initial slope, rise time, and peak value of the pyroelectric response to step radiation signals, valid for temperatures up to the Curie point. An experiment carried out on single-crystalline triglycine sulphate has yielded the temperature dependence of λ and ε with reasonable accuracy and in good agreement with other methods.
Synchronously pulsed ir up-conversion
Authors: Tseng David Y.
Published: January 2004

The successful operation of a synchronously pulsed high-repetition-rate ir up-converter is reported. Using a 1.06-μm Nd:YAG pump laser and a proustite (Ag3AsS3) nonlinear crystal, 10.6-μm pulsed output from a CO2 laser has been up-converted to 0.964 μm with good conversion efficiency and high peak power obtained. Up-conversion efficiency of 0.84% has been achieved, which generated peak power outputs of 8.4 W at 0.964 μm. This was accomplished at a repetition rate of 133 pps. Under these conditions, the beam of the up-converted signal was easily imaged and clearly visible on an ordinary S-1 surface-image intensifier tube. Thus, real time imaging or electronic image processing of ir-illuminated scenery should be possible using this mode of operation.
Surface-elastic-wave properties of dc-triode-sputtered zinc oxide films
Authors: Hickernell F.S. , Brewer J.W.
Published: January 2004

Measurements at frequencies above 200 MHz have been made of the coupling factor, phase velocity, and propagation loss of dc-triode-sputtered zinc oxide film layers on oxidized silicon and fused quartz. Values of 2.2% have been obtained for k2. Propagation losses of 8.0 dB/μsec were observed at 630 MHz. The measurements strongly suggest that sputtered zinc oxide films can be obtained whose quality approaches very closely that of single-crystal zinc oxide.
Thermally addressed electrically erased high-resolution liquid-crystal light valves
Authors: Melchior H. , Kahn Frederic J. , Maydan D. , Fraser D.B.
Published: January 2004

New highly transparent liquid-crystal light valves for the recording, storage, and display of high-resolution graphic images in projection displays are described. Information is recorded in these light valves by an x-y deflected intensity-modulated ir laser beam which locally heats visually transparent infrared absorbing electrodes. The resulting temporary heating of the cholesteric liquid crystal creates light-scattering centers that remain stored until erased electrically. Resolution is 50 lines/mm over a 4×4-cm area. Contrast is better than 10:1. Addressing speed is higher than 104 picture elements/sec for a few mW of 1.06-μm YAlG laser power.
Electromigration in conductor stripes under pulsed dc powering
Authors: English A.T. , Tai K.L. , Turner P.A.
Published: January 2004

Thin Ti–Au films on sapphire were powered using pulsed dc. The incidence of electromigration damage is a complex function of pulse duration and repetition rate. For a given total ``exposure'' (fixed current density for a fixed total on-time) the damage may be reduced or eliminated by using duty cycles less than 100%.
n-p junction ir detectors made by proton bombardment of epitaxial PbTe
Authors: Logothetis E.M. , Holloway H. , Varga A.J. , Johnson W.J.
Published: January 2004

Proton bombardment has been used to make n-p junction ir detectors from epitaxial PbTe films on BaF2 substrates. When cooled at 77°K, these detectors are background limited at f/0.8; further reduction of the field of view gives Johnson-noise-limited peak detectivities of 6×1011 cm Hz1/2W−1 at f/20. The peak quantum efficiencies are 0.40–0.47.
Penetration of a magnetic constriction by intense relativistic electron beams
Authors: Benford James , Ecker Bruce
Published: January 2004

An experiment to observe propagation and compression of an intense relativistic electron beam in a tapered linear pinch resulted in beam penetration of the magnetic field constriction at the discharge's narrow end, contradicting the single-particle model verified in earlier experiments using axially uniform pinches. Transverse beam pressure overcame the net pinch pressure, expanding the magnetic constriction and allowing beam passage.
Avalanche-injected hole current in SiO2
Authors: Verwey J.F.
Published: January 2004

Results are given on the current of holes through an insulating double layer of SiO2 and Si3N4 on silicon. The holes originated from an avalanching p-n junction in the silicon and were injected into the SiO2. The results can be explained by assuming a space-charge-limited hole current in the SiO2 in the presence of traps exponentially distributed in energy. A value of about 10−3 cm2V−1 sec−1 was found for μ, the hole mobility in the SiO2.
Flux reversal in single-crystal MnBi platelets by vacuum deposition
Authors: Honda Shigeo , Konishi Susumu , Kusuda Tetsuzo
Published: January 2004

The magnetic properties of single-crystalline platelets of MnBi were studied with the aid of the Kerr effect, and some physical properties were analyzed by using an x-ray microanalyzer. The hysteresis loop has reentrant characteristics, and the coercive force is very small. A domain spot nucleated by thermal writing continues to expand by wall motion, and finally the platelet is almost demagnetized.
Lateral photovoltaic effect in nitrogen-implanted p-type silicon
Authors: Niu Hirohiku , Matsuda Tetsuro , Yamauchi Kenji , Takai Munezo
Published: January 2004

Nitrogen ions (N2+) are implanted into p-type Si samples to a dose of 6×1014 cm−2 at 10 keV. When the samples, annealed at temperatures higher than 535°C, are irradiated nonuniformly, photovoltages are observed parallel to the implanted surface. This lateral photovoltaic effect has confirmed that an n-type layer is formed by nitrogen implantation. The lateral photovoltage is a linear function of the irradiation position. The dependence of the photovoltage on irradiation wavelength (0.70–1.40 μ) and on anneal temperature (up to 850°C) has also been investigated.
Beam-induced lattice disorder in channeling experiments on Si and Ge
Authors: Campisano S.U. , Foti G. , Grasso F. , Rimini E.
Published: January 2004

The disorder produced by 0.3-MeV D+ random bombardment in Si and Ge crystal targets has been investigated with 1.5-MeV D+ channeling measurements. An increase of about 30–50% in the 〈111〉- and 〈110〉-aligned yields of Ge samples has been found after a bombardment with a dose of 200–300 μC/cm2. No significant increase was observed in bombarded Si samples. Detailed angular scans suggest a ``spread-out'' distribution of defects imbedded in the lattice structure.
Electron diffusion length in solution-grown GaAs : Ge
Authors: Ashley K.L. , Carr D.L. , Romano-Moran Roberto
Published: January 2004

The optical microprobe is used to measure electron diffusion lengths in solution-grown p-type layers of Ge-doped GaAs. They are found to be ∼ 20 μ, which gives an electron lifetime of ∼ 5×10−8 sec.
Fused-silica-core glass fiber as a low-loss optical waveguide
Authors: Kato Daisuke
Published: January 2004

A new type of glass fiber is discussed. The core of the fiber is pure fused silica, and the cladding is a high-silica-content glass. This type of glass fiber has potentially the lowest attenuation of light propagation. A light attenuation of approximately 20 dB/km was measured at a 632.8-nm wavelength in the preliminary work.
Channel optical waveguide directional couplers
Authors: Somekh S. , Garmire E. , Yariv A. , Garvin H.L. , Hunsperger R.G.
Published: January 2004

We report the first demonstration of channel optical waveguide directional couplers. The closely spaced channel waveguides were fabricated in GaAs by proton implantation. Optical coupling was observed at 1.15 μ with complete light transfer out of the initial channel into adjacent channels in lengths of typically 2 mm.
Quartz optical waveguide by ion implantation
Authors: Wei David T.Y. , Lee William W. , Bloom Louis R.
Published: January 2004

We have shown single-mode surface optical waveguiding in lithium-ion-implanted fused quartz, and multimode buried waveguiding in argon- and lithium-ion-implanted fused quartz. Guide losses are observed to be of the order of 5 dB for the samples investigated for both species of ions. Described in this letter are the experimental procedures and parameters for ion implantation and the measurements for mode behavior as compared to theoretical models.
Acoustic surface wave Δv/v waveguides on anisotropic substrates
Authors: Coldren L. A. , Schmidt R. V.
Published: January 2004

Accurate measurements of the phase and group velocity dispersion curves have been made for Δv/v waveguides on (001) 〈 110 〉 Bi12GeO20. The measurements are shown to be in good agreement with the results of a simple theory which includes the effect of substrate anisotropy. Results indicate that the acoustic energy is bound more tightly to waveguides fabricated on crystal orientations where anisotropy provides a reduced diffraction loss for unguided waves.
Range distribution of implanted ions in SiO2, Si3N4, and Al2O3
Authors: Chu W.K. , Crowder B.L. , Mayer J.W. , Ziegler J.F.
Published: January 2004

Backscattering measurements with 2.0-MeV He+ ions were used to determine the range distribution of Zn, Ga, As, Se, Cd, and Te implanted in SiO2, Si3N4, and Al2O3 at energies between 150 and 300 keV. Values of the projected range were systematically greater than LSS predictions by factors of 1.2–1.5. In normalized LSS units, the projected range, ρp, as a function of energy, ε, consistently followed within experimental error the relation ρp=2.7ε, where an arithmetic average atomic number of 10 and arithmetic average atomic mass of 20 apply to all three target species.
Strain-induced instability of monodomain smectic A and cholesteric liquid crystals
Authors: Clark Noel A. , Meyer Robert B.
Published: January 2004

A mechanism is proposed for the observed mechanical instability of monodomain smectic A and cholesteric liquid crystals subjected to uniaxial dilative stress. The threshold conditions for the instability are derived, and the possible roles of dislocations in controlling the instability and in producing large plastic distortions are discussed.
Role of magnetic fields in suprathermal particle generation by laser-produced plasmas
Authors: Tidman D.A. , Stamper J.A.
Published: January 2004

In this note we first use a simple circuit model to summarize the properties of the strong magnetic fields generated in laser-produced plasmas. It is pointed out that these fields are expected to increase the efficiency of suprathermal particle production near the critical depth. They would also cause energetic electrons to drift into the overdense regions of the target, giving rise to some emission of high-energy x rays.
Optically pumped GaAs surface laser with corrugation feedback
Authors: Nakamura M. , Yariv A. , Yen H.W. , Somekh S. , Garvin H. L.
Published: January 2004

A GaAs distributed-feedback laser was fabricated and pumped optically. A narrow stimulated spectrum was obtained around 0.83 μ with threshold pumping power of ∼2 × 105 W/cm2.
Shock-wave termination of laser action in coaxial flash lamp dye lasers
Authors: Ewanizky T.F. , Wright R.H. , Theissing H.H.
Published: January 2004

Shock-wave-induced optical distortion of dye laser solutions in conventional coaxial flash lamps has been observed. An inwardly propagating radial shock wave is generated in the solution upon flash lamp discharge, causing virtually complete scattering of axially directed light within a few microseconds. Laser action is prematurely terminated since rapidly induced optical distortion becomes a substantial impediment during the period of effective laser pumping.
Ge-doped p-type epitaxial GaAs for microwave device application
Authors: Rosztoczy F.E. , Caldwell J.F. , Kinoshita J. , Omori M.
Published: January 2004

GaAs p-n junctions were grown by liquid-phase epitaxy using Ge as the acceptor and Sn as the donor. Abrupt junctions with well-controlled carrier concentrations in both the n and the p layers were produced. High-quality varactors and double-drift GaAs IMPATT diodes were fabricated. cw output power of 3.0 W with 15.8% efficiency at 8.9 GHz and pulse output power of 4.1 W with 20.7% efficiency at 10.56 GHz were observed.
Laser pulse shaping due to self-phase modulation in amplifying media
Authors: Fleck J.A. , Carman R.L.
Published: January 2004

It is shown experimentally that high-power laser pulses amplified in ruby can display strong frequency-modulated characteristics due to the refractive-index nonlinearity of the medium. Theoretical calculations of the coherent pulse amplification under similar circumstances show that self-phase modulation causes asymmetric pulse shaping due to adiabatic passage effects.
Measurement of density and temperature of a hydrogen plasma using an argon laser
Authors: Billman Kenneth W. , Stallcop James R.
Published: January 2004

Curves relating the absorption of the argon ion laser lines at 0.488 and 0.515 μm to the electron density and plasma temperature of a hydrogen plasma are presented. A technique for determining these plasma parameters by means of simple absorption measurements is discussed.
Plasma chemistry of CO2 –N2 –He discharges
Authors: Wiegand W.J. , Nighan William L.
Published: January 2004

Analysis of plasma-chemical phenomena occurring in electrically excited mixtures of CO2, N2, and He has shown that the principal dissociation products CO and O accumulate to significant levels in approximately 10−4 sec, a time less than typical fluid residence times in convection lasers. In addition, numerous secondary minority species are produced on the same time scale, reaching concentrations significantly in excess of the charge particle densities. The dominant ionic species are found to be directly related to these discharge-generated minority species. These investigations have shown that negative ion concentrations can become comparable to the electron concentration for typical laser discharge conditions.
Laser-induced shock effects in Plexiglas and 6061-T6 aluminum
Authors: Fox Jay A. , Barr Dallas N.
Published: January 2004

The mass removal per unit area from Plexiglas and 6061-T6 aluminum targets irradiated in air with a giant pulsed laser is presented as a function of incident fluence. This quantity appears to be a strong function of the focal length of the focusing lens. Air breakdown in the presence of a target occurs at fluences greater than 380 J/cm2 for Plexiglas targets and 159 J/cm2 for aluminum targets. Photographic evidence of the back-face spallation of a 0.1-cm-thick aluminum sample irradiated in vacuum is presented. The mirror-finished target was inclined at 45° to the incident beam and irradiated with a fluence of approximately 5000 J/cm2.
Negative differential resistivity in superconductors at high current densities
Authors: Huebener R.P. , Gallus D.E.
Published: January 2004

In the current-induced resistive state of superconducting strips the voltage shows detailed structure as a function of the transport current. This structure is associated with the rearrangement within the sample of currents and magnetic fields. We report the observation of current regimes with negative differential resistivity in microstrips of the superconducting alloy Pb-5 at.% Bi.
Permanent multipole magnetic fields stored in superconductors
Authors: Garwin Edward L. , Rabinowitz Mario , Frankel David J.
Published: January 2004

Hollow superconducting cylinders of Pb, Nb, and Nb3Sn were used to permanently store dipole, quadrupole, and sextupole magnetic fields with high fidelity to the original fields. Fields were trapped transversely to the axes of solid, hollow, and split hollow cylinders. This experimental demonstration indicates that it should be possible to store any multipole magnetic field configuration by this method. Important benefits should accrue to technologies dealing with the focusing of charged particle beams, such as accelerators, electron microscopes, etc. Use of field trapping permits determination of the fluxoid pinning force.
Demonstration of the superconducting electron accelerator as a high-intensity high-resolution device
Authors: McAshan M.S. , Mittag K. , Schwettman H.A. , Suelzle L.R. , Turneaure J.P.
Published: January 2004

In recent experiments with the superconducting injector system, beam intensity and beam quality objectives for the superconducting electron accelerator have been achieved and exceeded. At 8.5 MeV and 25 μA, spreads in phase and energy of 1.2° and 9.2 keV fullwidth at half-maximum, respectively, have been measured, and at 250 μA the spreads in the phase and energy increased by only 10%.
Dependence of laser-induced breakdown field strength on pulse duration
Authors: Fradin D.W. , Bloembergen N. , Letellier J.P.
Published: January 2004

Field strengths at which optical damage is initiated in NaCl have been measured with a mode-locked Nd: YAG laser with pulse durations of 15 and 300 psec. Comparison with previously reported data with a Q-switched laser shows that the field strength required for intrinsic optical damage increases by almost one order of magnitude from 106 V/cm at 10−8 sec to over 107 V/cm at 1.5 × 10−11 sec. This is in qualitative agreement with published estimates based on the electron avalanche breakdown mechanism.
Interactions between slow circuit waves and drifting carriers in InSb and Ge at 4.2°K
Authors: Freeman J.C. , Newhouse V.L. , Gunshor R.L.
Published: January 2004

Substantial interactions between drifting carriers in a semiconductor and slow circuit waves on meander lines have been demonstrated for the first time. Electronic gains in the meander-meander line signal of up to 40 dB/cm were obtained with Ge at 4.2°K. Although no net gain was achieved with respect to the ports of the meander lines due to the structure's high transmission loss of 20–30 dB, the results demonstrate the possibility of solid-state slow-wave amplification which has been the subject of many previous theoretical studies.
Intense superradiant emission at 496 μm from optically pumped methyl fluoride
Authors: DeTemple T.A. , Plant T.K. , Coleman P.D.
Published: January 2004

Intense superradiant emission has been observed from methyl fluoride excited by 0.6-MW pulses from a high-pressure CO2 laser. Pulses of ∼ 1 kW with a duration of ∼ 150 nsec have been obtained from a 5-m-long 40-mm-diam cell containing 0.7 Torr of methyl fluoride. This output represents an efficiency of converting infrared photons to far-infrared photons of ∼ 5%. Evidence for partial waveguiding in the cell and for phase-coherent amplification are presented.
Laser oscillation from Ho3+ and Nd3+ ions in epitaxially grown thin aluminum garnet films
Authors: van der Ziel J.P. , Bonner W.A. , Kopf L. , Singh S. , Van Uitert L.G.
Published: January 2004

Pulsed and continuous laser operation of the Ho3+ 5I7→5I8 transition at 2.1 μm has been obtained at 77°K by using Y1.25Ho0.1Er0.55Tm0.5Yb0.6 Al5O12 thin films grown on Y3Al5O12 substrates. Oscillation at the 1.06-μm 4F3/2→4I11/2 transition of Nd3+ has also been observed at 77 and 300°K from Y3Al5O12:Nd3+ films. The characteristics of these thin-film waveguide lasers are discussed.
Supersonic mixing nozzle for gas-dynamic lasers
Authors: Borghi R. , Carrega A.F. , Charpenel M. , Taran J.-P.E.
Published: January 2004

A supersonic mixing nozzle for CO2 gas-dynamic lasers is presented. It is shown that satisfactory mixing can be obtained with an increase of the freeze efficiency over simple expansion nozzles for premixed flows. Gain constants in the vicinity of 3% cm−1 are found, and a twofold improvement of the thermal-to-optical conversion efficiency over conventional GDL is predicted.
Amplification competition in a double-cavity flash-pumped dye laser
Authors: Dezauzier Pierre , Eranian Armand , de Witte Olivier
Published: January 2004

A double-cavity technique was used to control the duration of the flash-pumped dye laser emission. Interaction between the two cavities of perpendicular polarization was possible because of the very rapid orientational relaxation of the dye in solution. 30-ns pulses were obtained with a water solution of rhodamine 6G excited with a fast coaxial flash lamp.
A self-stabilized 3.5-μm waveguide He–Xe laser
Authors: Smith P.W. , Maloney P.J.
Published: January 2004

By building a He–Xe laser within a hollow dielectric waveguide and by using a single isotope of Xe, we have been able to attain gains of 1000 dB/m. The dispersion associated with these large gains significantly modifies the ``empty-resonator'' mode spacing when such a medium is placed within a laser resonator. We describe experiments with a short single-frequency waveguide He–Xe laser in which the gain medium pulls the oscillating frequencies so that the laser always oscillates within ± (1/100) (c/2L) of the center of the Xe net-gain curve, regardless of the physical length of the laser resonator.
Continuous uniform excitation of medium-pressure CO2 laser plasmas by means of controlled avalanche ionization
Authors: Hill Alan E.
Published: January 2004

A sequence of 50- to 75-nsec high-voltage pulses in combination with photoionization produce spatially uniform continuous electron densities of 2 × 1011 with a 10–20% ripple at 20 000 Hz in 150-Torr CO2 laser mixes. A separate continuous electric field ranging from 3 to 6 kV/cm atm is used to heat the electrons, which loads greater than 0.25 J/cm3 atm into the plasma without arc breakdown. As is the case with electron beam plasmas, E/P and ne may be controlled independently. Hence, electron beams, flow constrictions, etc., are not necessary to produce uniform plasmas for cw high-power electric gas laser systems.
Suppression of hard bubbles in magnetic garnet films by ion implantation: Dependence on ion species, dose, energy, and annealing
Authors: Wolfe R. , North J.C. , Lai Y.P.
Published: January 2004

Hard bubbles in typical bubble garnets can be eliminated by ion implantation which produces a layer of planar magnetization at least a few hundred angstroms thick. Neon at doses in the 1014-ions/cm2 range is as effective as hydrogen at doses in the 1016-ions/cm2 range in suppressing hard bubbles without effecting domain wall coercivity or mobility. Annealing studies have shown that the thermal stability of the effect increases with increasing dose and decreasing energy of implantation and is sufficient to withstand maximum device processing temperatures and assure long lifetimes.
Solid-phase epitaxial growth of Si mesas from al metallization
Authors: Sankur H. , McCaldin J.O. , Devaney John
Published: January 2004

Si epitaxial growth from solution in solid Al onto crystal Si substrates was studied by scanning electron microscopy. Growth in reentrant corners of the substrate was found to be favored over growth onto a flat surface. For this reason, the smaller-diameter oxide cuts used in integrated-circuit fabrication, in which no portion of the exposed substrate Si is far from a reentrant corner, are favored sites for growth. Si growth readily fills in such oxide cuts forming mesa structures potentially useful in device construction. The probable cause for such preferential growth was indicated in pressure experiments which show that regions in the solid Al under relatively less compression are favored locations for growth.
Memory behavior of metal-plasma-anodized Al2O3 and SiO2-semiconductor (MAOS) capacitors
Authors: Pappu R.V. , Boothroyd A.R.
Published: January 2004

Fabrication details and experimental results are presented for metal-Al2O3-SiO2-silicon capacitors intended as memory devices, for which the insulator layers are formed by plasma anodization. It is found that well-controlled devices with stable characteristics may be realized by this method.
Efficient pulsed optical parametric oscillator with a tuning range from 0.415 to 2.1 μm
Authors: Nath G. , Pauli G.
Published: January 2004

A LiIO3 crystal, placed inside a doubly resonant oscillator, was pumped with the second harmonic of a Q-switched ruby laser. A 0.415- to 2.1-μm tuning range for both signal and idler was obtained. The conversion efficiency from pump to signal power amounts to 8%. The peak power of the signal radiation was 10 kW and the pulse duration was 5 nsec.
Surface depletion of InSb by SiO and CaF2
Authors: Luo F.C. , Epstein M.
Published: January 2004

Increase in resistance of thin films of InSb with thickness of vacuum-deposited overlays of SiO and CaF2 indicates surface depletion in the semiconductor. Also, the equivalent depletion depth and the net trapped charge are evaluated for the case of a CaF2 insulator.
ir-laser-addressed thermo-optic smectic liquid-crystal storage displays
Authors: Kahn Frederic J.
Published: January 2004

Thermally induced optical storage and erasure (local and nonlocal) of scattering centers in thin films of smectic liquid crystals has been demonstrated. These new thermo-optic and electrothermo-optic effects provide the basis for what is believed to be the first practical application of smectic liquid crystals, an infrared-laser-addressed light valve for the recording, storage, and display of high-resolution graphic images.
Preswitching and postswitching phenomena in amorphous semiconducting films
Authors: Shaw M.P. , Moss S.C. , Kostylev S.A. , Slack L.H.
Published: January 2004

Low-duty-cycle pulsed dc switching experiments have been performed on a variety of thin-film Te-based semiconducting glasses. No premonitory effects are observed in the current-time profile of the nonswitching off state. If, however, the threshold voltage is exceeded, a continuous current increase with time throughout the normal delay-time regime (preswitching off state) is always observed prior to switching. In a given device or film this current rise is interrupted, independent of overvoltage, by the rapid switching transition at about the same relative current increment above the current background extrapolated to zero time (leakage current). In the switched or on (filamentary conduction) state the current level, as limited by the series load resistor, can condition the response of the device in the subsequent preswitched off state. For loads in excess of ∼1 kΩ, there is no effect on the preswitching off state characteristics whereas, for appreciably smaller loads, there is a continuous increase in delay time with increased pulse length (time spent in the previous on state). The results (i) indicate that the development of a filamentary instability begins at the onset of the pulse and (ii) show that the operating threshold voltage can be raised (returned to its virgin value) when the operating current is large for a sufficiently long time. These features are consistent with switching models that treat the ``formed'' switching element as a high-conductance-formed filamentary region (of not necessarily uniform composition) surrounded by a low-conductivity glass.
Stimulated emission from PrCl3
Authors: German K.R. , Kiel A. , Guggenheim H.
Published: January 2004

We have investigated the fluorescent and stimulated emission properties of PrCl3 as a function of the pump laser wavelength, pump power, and temperature. The previously reported laser emission at 645.2 nm has been studied at 295°K and at lower temperatures. At low temperatures we have observed stimulated emission at three new wavelengths, 616.8, 529.8, and 489.2 nm. The linewidths and lifetimes of various optical transitions have been measured and related to the observed optical gain at the above wavelengths. We have also observed stimulated output in 1% Pr in LaCl3.
Optically pumped N2O laser
Authors: Chang T.Y. , Wood O.R.
Published: January 2004

Laser action at 10.8 μm has been obtained in pure N2O gas at pressures up to 270 Torr by optically pumping with the 4.465-μm line of a TEA HBr laser. Possible extension of this pumping technique to other linear three-atomic molecules and molecules with a linear three-atomic skeletal is discussed.
An efficient electrical CO2 laser using preionization by ultraviolet radiation
Authors: Judd O.P.
Published: January 2004

Investigations of a large-volume high-pressure pulsed electrical CO2 laser that employs volumetric photopreionization of the gas by ultraviolet radiation are reported. An optical energy extraction of 40 J/literatm at 700 Torr and a conversion efficiency of 24% have been obtained.
Study of the geometrical resonances of superconducting tunnel junctions
Authors: Soerensen O. Hoffmann , Finnegan T.F. , Pedersen N.F.
Published: January 2004

The resonant cavity structure of superconducting Sn-Sn-oxide-Sn tunnel junctions has been investigated via photon-assisted quasiparticle tunneling. We find that the temperature-dependent losses at 35 GHz are determined by the surface resistance of the Sn films for reduced temperatures between 0.5 and 0.8. Our results are in very good agreement with the microscopic theory of Mattis and Bardeen for the surface resistance of Sn.
Distributed-feedback lasers in optical waveguides deposited on anisotropic substrates
Authors: Bjorkholm J.E. , Sosnowski T.P. , Shank C.V.
Published: January 2004

We have investigated some of the properties of distributed-feedback lasers constructed in thin-film optical waveguides deposited on anisotropic substrates. We describe TE or TM mode suppression, frequency tuning by varying the propagation direction relative to the substrate optic axis, and the generation of unexpected frequencies via a new type of distributed-feedback interaction.
Hybrid scattering in periodic waveguides
Authors: Kogelnik H. , Shank C.V. , Bjorkholm J.E.
Published: January 2004

A mechanism for frequency generation which can occur in waveguide distributed-feedback lasers on anisotropic substrates is discussed. The proposed mechanism is a hybrid Bragg scattering between oppositely travelling waves with orthogonal polarizations. It explains the frequency spectrum observed in the preceding letter, which occurs as a result of the simultaneous presence of two coupled-wave phenomena: mode conversion due to the anisotropic substrate, and backward Bragg scattering due to the periodic waveguide structure.
Josephson junction analog and quasiparticle-pair current
Authors: Bak C.K. , Pedersen N.F.
Published: January 2004

A close analogy exists between a Josephson junction and a phase-locked loop. A new type of electrical analog based on this principle is presented. It is shown that the inclusion in this analog of a low-pass filter gives rise to a current of the same form as the Josephson quasiparticle-pair current. A simple picture of the quasiparticle-pair current, which gives the right dependences, is obtained by assuming a junction cutoff frequency to be at the energy gap.
Noise reduction in acousto-optic (Bragg) imaging systems by holographic recording
Authors: Winter Donald C.
Published: January 2004

The high noise level of acousto-optic images is reduced by utilizing the frequency difference between the image and noise light. A hologram is made of the acousto-optic image with a reference beam having a frequency equal to that of the image light. As the noise light is of a different frequency, it is not holographically recorded. When the holographic image is observed, only a duplicate of the acousto-optic image is seen, free of the background noise. Acousto-optic images 10 dB below noise level have been detected using this technique.
Comparison of laser-induced surface and bulk damage
Authors: Fradin D.W. , Bass Michael
Published: January 2004

Data are presented which show that the optical field required to produce damage on a conventionally polished surface of a transparent medium is less than that required to damage an imperfection-free surface. Electric field enhancement at imperfections can explain this result. In addition, the bulk damage field at 1.06 μm is reported for three materials and is found to be the same as the surface damage field on imperfection-free surfaces.
On the mechanism for microwave amplification in ``supercritically'' doped n-GaAs
Authors: Spitalnik R. , Shaw M.P. , Rabier A. , Magarshack J.
Published: January 2004

Good agreement is obtained between experiment and numerical calculations on supercritically doped n-GaAs transferred electron amplifiers. When moderate doping depletions near one electrode are included in the calculations, the results correctly predict the small-signal impedance and current-voltage characteristics, including the bias-induced stable-unstable-stable regimes. The results demonstrate the dominant role played by the electrodes in controlling the behavior of transferred electron amplifiers.
Study of silicon-oxygen interaction with the statical method of secondary ion mass spectroscopy (SIMS)
Authors: Benninghoven A. , Storp S.
Published: January 2004

The interaction of O2 with atomically clean Si surfaces has been studied by UHV secondary ion mass spectroscopy (SIMS). Thermally cleaned and annealed Si (111) surfaces, as well as ion-bombarded Si (111) surfaces, have been investigated. The silicon-oxygen interaction was found to take place in two steps. In step (i) a monoatomical oxide layer on the surface is formed with an initial sticking coefficient for O2 of about 1 and 0.05 for Si (111) and ion-bombarded Si (111), respectively. In step (ii) this monoatomical layer grows very slowly into greater depth.
Push clocks: a new approach to charge-coupled devices clocking
Authors: Mohsen A.M. , McGill T.C. , Anthony Michael , Mead C.A.
Published: January 2004

A new approach to charge-coupled device clocking has been developed—dynamic push clocks. With dynamic push clocks, the charge is transferred by pushing it from one storage site to another. The push clock approach results in a larger signal dynamic range, larger signal-to-noise ratio, and better performance at both high and low frequencies.
Comparison of sources of boron, phosphorus, and arsenic ions
Authors: Wilson R.G. , Jamba D.M.
Published: January 2004

A number of boron, phosphorus, and arsenic compounds, viz., B2H6, B10H14, B3N3H6, B2S3, BF3, BCl3, BBr3, BI3, HBO2, P, PH3, PF3, PF5, PCl3, POCl3, P2O5, As, AsH3, AsF3, AsCl3, and As2O5, are compared as sources of boron, phosphorus, and arsenic ion beams in a hot-filament electron-impact or oscillating-electron-discharge (OED) ion source. Performance comparison data, including the percentage of B+, P+, P2+, P+2, As+, As2+ and As+2 in the total beam and the maximum ion currents observed at the target of a 150-kV ion implantation system, are given for a common set of source and system conditions. BF3 and BCl3 are evaluated as the first and second best materials for B+, with any other compound providing only a poor third choice. The pure elements P and As provide large currents of both monatomic and diatomic ions and have no other interfering ion components. PH3 is a good source of P+ but has strong nearby hydride ions. The fluorides of P and As provide good currents of monatomic ions and have proved convenient to use.
High-pressure iodine photodissociation laser
Authors: Aldridge F.T.
Published: January 2004

An iodine photodissociation laser has been operated at 600 Torr by adding inert gas to the laser medium. The inert gas does not quench the inversion. Pressure broadening of the 1.315-μ emission line with an inert gas is a simple and effective method of increasing the energy storage capacity of the laser for short-pulse amplification.
High-frequency cutoff periodic dielectric waveguides
Authors: Dabby F.W. , Saifi M.A. , Kestenbaum A.
Published: January 2004

We report high-frequency cutoff in periodic dielectric waveguides. The guides consisted of 1-μ photoresist film with a surface corrugation of up to 500 Å overlaid on fused silica substrates. At a wavelength of 1.064 μ we obtained transition between complete cutoff and propagation by variation in the periodicity of the guide of ± 30 Å. For gratings having 500-Å corrugation, unobstructed propagation at 1.32 μ occurred with complete stopping of 1.064-μ light.
Accurate frequencies of molecular transitions used in laser stabilization: the 3.39-μm transition in CH4 and the 9.33- and 10.18-μm transitions in CO2
Authors: Evenson K.M. , Wells J.S. , Petersen F.R. , Danielson B.L. , Day G.W.
Published: January 2004

The frequencies of three lasers stabilized to molecular absorptions were measured with an infrared-frequency synthesis chain extending upwards from the cesium frequency standard. The measured values are 29.442 483 315 (25) THz for the 10.18-μm R(30) transition in CO2, 32.134 266 891 (24) THz for the 9.33-μm R(10) transition in CO2, and 88.376 181 627 (50) THz for the 3.39-μm P(7) transition in CH4. The frequency of methane, when multiplied by the measured wavelength reported in the following letter, yields 299 792 456.2(1.1) m/sec for the speed of light.
Electron avalanche breakdown induced by ruby laser light
Authors: Fradin David W. , Bass Michael
Published: January 2004

Ruby-laser-induced intrinsic bulk damage in nine alkali-halide crystals is reported. Within experimental error and for all of these crystals the damage field is greater than or equal to that measured at 1.06 μm and dc. The trend in breakdown fields among these crystals at 0.69 μm differs from that at longer wavelengths and suggests that, even though electron avalanche breakdown is the likely damage mechanism, the first signs of a frequency dependence to this process appear by 4.3×1014 Hz.
Impulse loading of targets by subnanosecond laser pulses
Authors: Metz S.A.
Published: January 2004

Measurements of the impulse received by graphite and aluminum targets exposed to a 250-psec laser pulse are reported. Experiments were conducted in air and vacuum at incident energies between 0 and 20 J. In both environments, there is a definite energy threshold, which is lower in air than in vacuum, below which no momentum is transferred. For a given energy above threshold, the impulse generated in air is greater than in vacuum.