bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental observations of the effects of oxide charge inhomogeneity on fast surface state density from high−frequency MOS capacitance−voltage characteristics
Authors: McNutt M. J. , Sah C. T.
Published: February 2003

It is demonstrated experimentally that the observed surface density of state peaks near the band edges, obtained from the Terman analysis of the capacitance−voltage characteristics of silicon MOS capacitors, can be attributed to areal inhomogeneities of oxide charges. An excellent quantitative match between theory and experiment is obtained after an extension of the theory of the C−V characteristics of inhomogeneous samples to include the real surface state densities.
Image scanning through the acousto−optical effect produced by acoustic surface waves
Authors: Alippi A. , Palma A. , Palmieri L. , Socino G.
Published: February 2003

The scanning of a transparency is done by letting a collimated light wave front illuminate it and be diffracted by very short pulses of ultrasonic surface waves. Detection of diffracted light follows a time dependence that equals the transparency brightness along each line that is successively scanned. 94−MHz wave trains, about 10 wavelengths long, give a potential number of resolved spots per second almost equal to 107. Interaction geometry by back−surface reflection has been used, which greatly enhances the diffraction efficiency and yet retains the large acousto−optical bandwidth proper to surface waves.
Thickness dependence of acousto−optic diffraction efficiency in ZnO−film optical waveguides
Authors: Kushibiki J. , Sasaki H. , Chubachi N. , Mikoshiba N. , Shibayama K.
Published: February 2003

The thickness dependence of the efficiency of the Bragg diffraction between the same optical modes (TE0→TE0, TM0→TM0) by acoustic surface waves in ZnO−film optical waveguides is investigated at an acoustic frequency of 130 MHz and a film thickness from 0.6 to 8.0 μm. It is observed that the efficiencies for both the TE0 and the TM0 modes vary more than 2 orders of magnitude with the film thickness.
Emission of intense microwave radiation from an automodulated relativistic electron beam
Authors: Friedman M.
Published: February 2003

High−power microwave radiation has been observed from the interaction of an intense relativistic electron beam and a cavity structure. The efficiency of conversion of electron kinetic energy into microwave radiation was about 20% with a total radiated power of order 500 MW. The mechanism responsible for the efficiency production of microwaves is based on a simple physical model.
Tapered section of multimode cladded fibers as mode filters and mode analyzers
Authors: Ozeki Takeshi , Ito Takao , Tamura Toshifumi
Published: February 2003

Mode filtering characteristics of biconical tapers in multimode fibers were examined. The insertion loss of a biconical taper for the HE11 mode is 0.2 dB and the rejection ratios for higher−order modes are more than 20 dB. The mode conversion in a biconical taper is sufficiently small except for the HE1n modes. It is found that a linearly tapered section can be used as a mode analyzer for multimode fibers.
LiNbxTa1−xO3 optical waveguiding layer in LiTaO3 fabricated by diffusion of LiNbO3 sputtered film
Authors: Minakata Makoto , Noda Juichi , Uchida Naoya
Published: February 2003

Thermal diffusion of a rf−sputtered LiNbO3 thin film into a LiTaO3 substrate has been investigated. By an appropriate choice of diffusion conditions, a single−mode waveguiding layer with the composition LiNbxTa1−xO3 has been fabricated. The refractive−index change at the surface is about 0.9×10−3 for both ne and no and the diffusion depth is 4.7 μm. The layer supports only the fundamental modes TE0 and TM0 and exhibits good waveguiding properties.
Field heat treatment of ferromagnetic metallic glasses
Authors: Chen H. S. , Ferris S. D. , Gyorgy E. M. , Leamy H. J. , Sherwood R. C.
Published: February 2003

The magnetic properties of zero magnetostrictive metallic glass have been investigated using both standard fluxmeter methods and domain patterns obtained from a scanning electron microscope technique. This investigation shows that the material is not magnetically isotropic but rather has preferred directions of magnetization that are determined by the details of the quenching process. The magnetic aniostropy produced by subsequent field anneal dominates the original anisotropy and determines the magnetic behavior after the heat treatment.
Low−temperature dielectric loss in polyethylene
Authors: Thomas R. A. , King C. N.
Published: February 2003

A calorimetric technique was used to accurately determine the dielectric loss tangent of both additive−free and commerical grades of polyethylene at liquid−helium temperature. We found that the loss tangent of polyethylene often exhibits a broadened dielectric relaxation peak. Although this peak is centered in the kilohertz region, its existence increases the loss tangent at 60 Hz. Thus, the possibility of the elimination or reduction of this peak is important in evaluating the suitability of polyethylene as an insulator for a superconducting ac power transmission line. We have measured the intrinsic dielectric loss tangent of polyethylne and have found it to be ∼5×10−6. In addition, by systematically studying the influence of chemical additives on the dielectric loss, we have found the conditions necessary to obtain polyethylene exhibiting this low loss using present industrial production methods.
Auger spectroscopy analysis of palladium silicide films
Authors: Thomas Simon , Terry L. E.
Published: February 2003

The formation of Pd2Si in Pd films sputter deposited on Si substrates and heated up to 400 °C has been studied by measuring the depth profile using Auger electron spectroscopy (AES) and Ar+ ion sputtering. Significant chemical effects in the silicon LVV Auger peak shape have been observed, enabling the easy differentiation of the silicide from elemental silicon. The depth profile indicated that the silicide phase is formed at the Pd/Si interface even in the unannealed films. In forming the silicide, the silicon atoms diffuse through the film and on arrival at the surface oxidize to form a thin layer of SiO2. Some of the problems encountered in the determination of the depth scale from the AES data are pointed out.
Enhanced nonlinear optical effects in rotationally twinned crystals
Authors: Dewey C. F. , Hocker L. O.
Published: February 2003

We have produced continuously tunable infrared radiation between 4 and 21 μm by mixing the outputs of a ruby laser and a ruby−pumped dye laser in a single rotationally twinned ZnSe crystal. The peak output power of 5 W at 4 μm is approximately 250 times larger than the power obtained from an untwinned ZnSe crystal of comparable length. This enhancement is attributable to randomly spaced rotational twin planes perpendicular to the direction of propagation. Regularly spaced twins should produce an enhancement proportional to the square of the number of twin planes.
Interferometric tuning of a 15−atm CO2 laser
Authors: O’Neill F. , Whitney W. T.
Published: February 2003

Efficient controlled frequency narrowing and tuning of a high−power 15−atm electron−beam−controlled CO2 laser has been achieved using a Fabry−Pérot etalon as a dispersive element in the laser resonator. Tuning has been accomplished over the free spectral range of the etalon (∼2.3 cm−1) giving a laser linewidth of <0.2 cm−1 for an output pulse energy ∼100 mJ in a spot size ∼1 mm2. The laser pulse length is ∼40 nsec for a peak power ∼5 MW.
The use of a phase diagram as a guide for the growth of PbTe films
Authors: Lopez−Otero A.
Published: February 2003

A kind of pressure−composition (P−X) phase diagram was built for PbTe films grown by the hot−wall technique. This diagram proves to be a very valuable guide to prepare, reproducibly, films with a desired conduction type and carrier concentration. Although the diagram should not be interpreted as having general validity, we find that it has marked similarities with the equilibrium phase diagram obtained previously for PbTe.
Heterojunction diodes of (AlGa)As−GaAs with improved degradation resistance
Authors: Ettenberg M. , Kressel H.
Published: February 2003

The resistance to gradual degradation of (AlGa)As−GaAs heterojunction structures prepared by liquid phase epitaxy is shown to be greatly improved by using a very fast cooling rate. The specific diodes described are of interest as high−speed (200 MHz) LED sources for fiber−optic communications. It is suggested that the improved degradation resistance results from a reduction in the arsenic vacancy concentration incorporated in the GaAs grown at the high cooling rates.
Observation of the intrinsic noise of a thin−film microbridge Josephson junction
Authors: Pei S. S. , Lukens J. E.
Published: February 2003

We have measured the intrinsic noise of a thin−film microbridge Josephson junction included as part of a closed superconducting ring. This microbridge, which was fabricated using electron beam lithography and has submicron dimensions, exhibited a noise magnitude which was in excellent agreement with that predicted for an ideal Josephson junction.
CO2 laser heating of plasma columns in a steady solenoid field
Authors: Rutkowski H. L. , Scudder D. W. , Pietrzyk Z. A. , Vlases G. C.
Published: February 2003

A 250−J CO2 laser has been used to produce plasma columns 12−20 cm in length, 2−4 mm in diameter, from initially uniform neutral hydrogen in a steady solenoidal field up to 100 kG. Interferometric and spectroscopic measurements indicate densities and temperatures on the order of 100 eV and 5×1017 cm−3, respectively. The backward−going laser−driven wave normally present in laser breakdown has been eliminated by pulsed filling of the tube.
Effects of dislocations on photoluminescent properties in liquid phase epitaxial GaP
Authors: Suzuki Tohru , Matsumoto Yoshishige
Published: February 2003

Correlations between photoluminescent decay time and dislocation density were studied in undoped liquid phase epitaxial GaP. Dislocations strongly reduce the photoluminescent decay time, especially in samples in which nonradiative recombination times (τ0) due to shunt paths other than dislocations are long. Dislocations were found to correspond to photoluminescence dark spots whose diameter is correlated with τ0. A quantitative model is presented, which is in good qualitative agreement with the observed photoluminescent−decay−time−versus−dislocation−density relationships.
Propagation of ultrasonic surface waves through molecular films
Authors: Jain M. C. , Jericho M. H.
Published: February 2003

The propagation characteristics of 75-MHz ultrasonic waves through molecular films of arachidic acid have been investigated. On thermal cycling through the melting temperature the ordered films break up into islands of disordered arachidic acid. With the help of an ultrasonic pulse-difference technique we could detect changes in the transmitted signal when arachidic acid islands as thin as 500 Å changed from the solid to the liquid state. It is suggested that similar experiments at higher frequencies could be of value in the investigation of phase changes and general structural properties of biological membranes.
Plasma-solid interaction in a theta pinch
Authors: Nunnally W. C. , Kristiansen M. , Hagler M. O.
Published: February 2003

The interaction of a dense high-temperature theta pinch plasma with 0.2-mm-diam spherical polystyrene pellets is reported. The pellets are not displaced by the plasma sheath implosion. They are not completely vaporized and the vaporized material is not ionized after many half-cycles of theta pinch action. The vaporized material remains neutral in the midst of the hot plasma for the duration of the experiment. The cloud ionization is increased by focusing a 1-J Q-switched ruby laser on the cloud after the initial plasma vaporization.
Atomic-displacement mechanism in ion-bombarded semiconductors and insulators
Authors: Dearnaley G.
Published: February 2003

A two-stage process of atomic displacement involving both elastic and inelastic energy transfer is presented, in order to account for the number and distribution of primary defects in ion-bombarded semiconductors and insulators. Some experimental tests are proposed.
Instant recording of the duration of a single mode-locked Nd:YAG laser pulse
Authors: Lompre L. A. , Mainfray G. , Thebault J.
Published: February 2003

An electro-optic streak camera incorporating a storage memory video system has been developed and used to instantly visualize and record the shape of a 1.06-μ-wavelength pulse generated by a mode-locked Nd:YAG laser. The duration of a single laser pulse (∼30 psec) has been directly measured with and without laser amplification.
High-efficiency multiply pulsed copper vapor laser utilizing copper chloride as a lasant
Authors: Chen Che J. , Russell Gary R.
Published: February 2003

A copper vapor laser operating at a wavelength of 5106 Å and a pulse repetition rate up to 30 000 pulses/sec has been constructed and investigated. The best results obtained to date are as follows: energy and power density of 35 μJ cm−3 and 1.7 kW cm−3; pulsewidth 20 nsec; average density 0.7 W cm−3; laser efficiency 1%.
Two-photon stimulated emission and pulse amplification
Authors: Yuen Horace P.
Published: February 2003

Threshold conditions are given for the sustained operation of standing-wave and long-pulse traveling-wave two-photon lasers. Pulse shortening in long-pulse two-photon amplification, a behavior absent in the one-photon case, is also demonstrated analytically.
Quasi-cw laser emission from the second positive band of nitrogen
Authors: Suchard S. N. , Galvan L. , Sutton D. G.
Published: February 2003

Experimental results are presented for the observation of a second positive nitrogen laser that has a pulse length much longer than the radiative lifetime of the upper laser level. Preliminary measurements of the temporal behavior of this laser indicate that it was operating in a quasi-continuous-wave manner and, in addition, the laser output was extremely sensitive to the alignment of the optical cavity placed around the discharge tube.
Solid-state oxygen meter using zinc oxide
Authors: Degn H. , Nobbs J. McK.
Published: February 2003

The electrical resistance of illuminated zinc oxide powder depends on the O2 content of a moist O2/N2 mixture. A model describing the relationship between R and pO2 is derived. The development of a practical solid-state O2 meter using zinc oxide seems possible.
Transient effects in wavelength-modulated dye lasers
Authors: Tang C. L. , Telle J. M. , Ghizoni C.
Published: February 2003

A new laser transient effect is observed in a wavelength-modulated cw dye laser. A theory for this effect is developed and shown to be in close agreement with the observed transients.
Equivalence of the coupled-mode and Floquet-Bloch formalisms in periodic optical waveguides
Authors: Yariv A. , Gover A.
Published: February 2003

A comparison of two theories used to analyze distributed feedback lasers and periodic optical devices finds them, contrary to some claims, to be formally equivalent.
Characterization of trapping kinetics from the lifetime dependence of thermally stimulated conductivity spectra
Authors: Rabie S. , Rumin N.
Published: February 2003

A technique is proposed for identifying trapping kinetics from thermally stimulated conductivity TSC) measurements, which is based on the influence of lifetime on TSC spectra. The same technique may be used to measure the trap energy if fast trapping dominates. The usefulness of the method is illustrated with some results of measurements on Zn-compensated silicon.
Silicon- and selenium-ion-implanted GaAs reproducibly annealed at temperatures up to 950 °C
Authors: Donnelly J. P. , Lindley W. T. , Hurwitz C. E.
Published: February 2003

A pyrolytic Si3N4 encapsulation technique has been used to permit reproducible annealing of implanted GaAs at temperatures as high as 950 °C. At low doses, electrical activity ≳70% has been achieved for both Si and Se. At high doses, sheet carrier concentrations and sheet resistivities of 1.8×1014/cm2 and 20 Ω/⧠, respectively, for Si and 7×1013/cm2 and 44 Ω/⧠, respectively, for Se have been measured.
Magnetization distributions in Permalloy bubble-domain propagation circuits
Authors: George P. K.
Published: February 2003

Recent magneto-optical measurements of the magnetization in Permalloy elements of bubble-domain propagation circuits yield magnetization profiles which are similar to those calculated on the basis of a continuum model. A quantitative comparison based upon scaling existing theoretical results for isolated elements confirms an interpretation of the data in terms of weakly interacting elements for the cases considered. The over-all comparison adds further evidence to support a continuum model for the magnetization in the Permalloy elements.
Negative ion species in CO2-N2-He discharges
Authors: Prince J. F. , Garscadden A.
Published: February 2003

The identification of the negative ion species created in a low-pressure CO2-N2-He electric discharge has been accomplished using an on-line quadrupole mass spectrometer. In a slow-flow 1-Torr cylindrical (22-mm-i.d.) discharge plasma, the prominent negative ions are NO−2, NO−3, O−2, O−, and CO−3. The changes in relative composition are presented for the current range 0.2–60 mA.
High-pressure glow discharge using a differentially pumped cathode
Authors: Tulip J. , Seguin H. J. J.
Published: February 2003

A high-pressure glow discharge in flowing gases is described. The cathode surface and the discharge glow are isolated by a mica sheet with a matrix of holes drilled into it. The cathode is differentially pumped to a pressure of approximately 1 Torr. This electrode structure has produced a discharge power density of 15 W/cm3 when the gas residence time is 3 ms.
Depth distribution of gallium ions implanted into silicon crystals
Authors: Dearnaley G. , Gard G. A. , Temple W. , Wilkins M. A.
Published: February 2003

Radioactive 72Ga+ ions have been implanted at room temperature into misoriented silicon crystals to a low fluence of 1013 ions/cm2. The resulting depth distribution, measured by anodic stripping, shows a prominent penetrating tail. Previously, such tails have been observed only in high-temperature bombardments and have therefore been attributed to an enhanced diffusion mechanism. It is shown that the scattering of ions into inclined planar or axial channels can account for all the Ga distributions observed. Some consequences for Si device fabrication are discussed.
Electro-optic amplitude modulation using three-dimensional LiNbO3 waveguide fabricated by TiO2 diffusion
Authors: Noda Juichi , Uchida Naoya , Saito Shoichi , Saku Tadashi , Minakata Makoto
Published: February 2003

An almost single-mode waveguiding layer has been fabricated by thermal diffusion of TiO2 into LiNbO3. The refractive-index change in the layer is 2–3×10−3 for both ne and no, and the propagation loss is 0.7–0.8 dB/cm. The electro-optic coefficients are found to be nearly equal to those of the bulk crystal. An amplitude modulation has been made with a stripe waveguide 10 μm wide and planar electrodes. The half-wave voltage is 17 V and the maximum extinction ratio is 12 dB.
Observation of adiabatic rapid passage utilizing narrow infrared saturation resonances
Authors: Hamadani S. M. , Mattick A. T. , Kurnit N. A. , Javan A.
Published: February 2003

Population inversion by adiabatic rapid passage (ARP) utilizing narrow saturation resonances is observed for an infrared transition of NH3. The population change produced by sweeping the frequency of a strong saturating laser field through the center of a Doppler-broadened absorption line is probed by a weak counterpropagating field as in a Lamb-dip experiment. When the ARP conditions are satisfied, inversion of population is detected as amplification of the probe wave near the line center.
Doped CO2 TEA laser
Authors: Reits B. J. , Olbertz A. H. M.
Published: February 2003

An extremely weak uv source conditions a large CO2 laser gas discharge with the aid of the seed gas tri-n-propylamine. With roughened Rogowski-shaped electrodes a glow discharge is achieved without a uv source. Evidence exists that the seed gas plays a role in the gas discharge itself.
Short-circuit capacitance of illuminated solar cells
Authors: Moore Arnold R.
Published: February 2003

The recently observed short-circuit capacitance of illuminated photovoltaic solar cells has been attributed to injection of minority carriers into the base by the perfectly shorted n-p junction, a result incompatible with conventional junction theory. In the present letter, this capacitance is treated as the result of voltage modulation of the space-charge width and subsequent redistribution of the minority carriers in the base, all in the context of conventional junction theory. Comparison with experimental results shows that this model gives the correct magnitude of the effect and predicts the dependence on spectral distribution of the illumination and the circuit test frequency.
Excitation of transversely excited CO2 waveguide lasers
Authors: Wood II O. R. , Smith P. W. , Adams C. R. , Maloney P. J.
Published: February 2003

Using a preionization scheme based on the Malter effect, small-signal gains ≳5%/cm at 10.6 μm ahve been produced in a 1-mm2-cross-section waveguide CO2 amplifier at total operating pressures of 100–760 Torr. Comparisons are made between this preionization scheme and those using electron beams.
High-power I2 laser in the 342-nm band system
Authors: Bradford R. S. , Ault E. R. , Bhaumik M. L.
Published: February 2003

Strong laser emission was observed in the 342-nm I2 band system from an e-beam–excited mixture of Ar and CF3I (250 : 1) at a total pressure of 10 atm. Laser emission occurred simultaneously at 342.0, 342.3, 342.4, and 342.8 nm with a peak power of 3.6 MW in a 10-nsec (FWHM) pulse.
Optimum tuning point of an optical parametric oscillator
Authors: Nelson D. F. , Mikulyak R. M.
Published: February 2003

We derive the mathematical condition for the existence in an optical parametric oscillator of an optimum tuning point (OTP), the point of maximum change of signal or idler frequency per unit perturbation by some applied influence. Computer calculations show that such a point exists in LiNbO3, KDP, ADP, LiIO3, and AgGaS2. A graphical interpretation of the OTP is presented. The pump frequency and crystal orientation at the OTP as well as expected tuning ranges for electric field tuning are given for the above five crystals.
Pulsed corona excitation of high-power uv nitrogen lasers at pressures of 0–3 bar
Authors: von Bergmann H. M. , Hasson V. , Preussler D.
Published: February 2003

Stabilized pulsed corona-type discharges can be used to pump uv laser efficiently at high pressures and on nanosecond time scales. This letter deals with the adaptation of this principle to the excitation of molecular nitrogen lasers at pressures ranging from 0 to 3 bar. Magewatt pulses of nanosecond duration may be obtained from a simple 25-cm atmospheric-pressure device. The electrical excitation is effected by a flat-plate Blumlein circuit.
Doubling acousto-optic deflector resolution utilizing second-order birefringent diffraction
Authors: Chang I. C. , Hecht D. L.
Published: February 2003

We have demonstrated operation of birefringent phase-matched TeO2 deflectors, utilizing the second optical diffraction order, which maintain high diffraction efficiency with doubled resolution. 1200-spot resolution was achieved with 25-μsec access time.
Nonlinear steering and mixing of acoustic waves in arsenic trisulfide
Authors: Rouvaen J. M. , Torguet R. , Bridoux E. , Haine F.
Published: February 2003

Very efficient mixing has been observed between a longitudinal wave and a transverse acoustic wave propagating noncollinearly inside an arsenic trisulfide delay line. The scattering of the longitudinal wave by the transverse one has also been investigated.
Correlation between blister skin thickness, the maximum in the damage-energy distribution, and projected ranges of He+ ions in metals: Nb
Authors: Kaminsky M. , Das S. K. , Fenske G.
Published: February 2003

The skin thicknesses of blisters formed on niobium by helium-ion irradiation at room temperature for energies from 100 to 1500 keV have been measured. The projected ranges of helium ions in Nb for this energy range were calculated using either Brice’s formalism or the one given by Schiott. For the damage-energy distribution Brice’s formalism was used. The measured skin-thickness values corrleate more closely with the maxima in the projected-range probability distributions than with the maxima in the damage-energy distributions. The results are consistent with our model for blister formation and rupture proposed earlier.
Diffraction effects in ferrofluids
Authors: Haas Werner E. L. , Adams James E.
Published: February 2003

Diffraction effects have been observed in ferrofluids in the presence of a magnetic field. The diffraction pattern from a laser beam normal to a thin layer of ferrofluid and normal to a magnetic field is confined to a plane also normal to the layer and normal to the field, indicating alignment of ferrofluid particles.
Controlled passive Q switch for the N2-laser-pumped dye laser
Authors: Braverman L. W.
Published: February 2003

A method for obtaining a single Q-switched laser pulse from dye lasers is presented. The method employs a passive Q switch triggered after time delay by a control beam. The delay time is adjusted until single high-power pulses are produced. Peak power in the dye laser is shown to increase by a factor of 6 due to the Q switch. The results are compared to solid-state laser theory.
Oxide thickness dependence of electron-induced surface states in MOS structures
Authors: Ma T. P.
Published: February 2003

To gain insight into the origin of the surface state induced by electron radiation, MOS structures with different oxide thicknesses were irradiated with a 25-keV electron beam. For a dose of 0.95×10−5 C/cm2, the surface states increased montonically as the oxide thickness increased from 90 to 2100 Å. Since all the oxides were grown under the same oxidation conditions and their initial surface states were of the same density, the results could not be due to the difference in their interface properties. The experimental results can be explained by a postulation based on a broken-bond model.
Photoemission study of the formation of Schottky barriers
Authors: Spicer W. E. , Gregory P. E. , Chye P. W. , Babalola I. A. , Sukegawa T.
Published: February 2003

For the first time, changes in electronic structure have been studied during Schottky barrier (Cs on GaAs or InP) formation. Strong changes occur near the valence band maximum; however, these do not overcome a dominant role of intrinsic surface states in Fermi-level pinning.
Reduction of classical thermal conductivity under the influence of high-power lasers
Authors: Pearlman Jay S. , Anthes John P.
Published: February 2003

Observation of the front and rear plasma expansions from a laser-irradiated thin film has been used to study the thermal conduction of polystyrene targets. The existence of reduced conductivity has been inferred above a threshold of 1014 W/cm2. The percentage of laser radiation transmitted through the thin film decreased by an order of magnitude as the laser flux increased from 1013 to 1014 W/cm2.
Electrical triggering of an optical breakdown plasma with subnanosecond jitter
Authors: Kwok H. S. , Yablonovitch Eli
Published: February 2003

We have shown that CO2-laser-induced breakdown in ultraclean gas follows less than 1 nsec after the injection of free electrons into the focal volume. While this confirms our understanding of the plasma nucleation mechanisms, it is also the first example of a new class of electro-optic switch in which a small electrical signal is able to control the transmission of a powerful laser beam.
Specific heat of cesium dideuterium arsenate (CsD2AsO4) from 0 to 120°C
Authors: Liu Yung S. , Shultz A. R.
Published: February 2003

The specific heat of cesium dideuterium arsenate (CsD2AsO4) was measured with a scanning differential calorimetric method in the temperature range from 0 to 120 °C. Using a least-squares curve fit, the power-series expression of the specific heat in this temperature range is found to be Cp(cal g−1 deg−1) =0.1111+1.80×10−4 T (°C)−5.9×10−9T2(°C). The specific heats at 25 and 100 °C are 0.1156±0.0005 and 0.1290±0.0005 cal g−1 deg−1, respectively. The crystal can be 90° phase matched for the nonlinear second-harmonic generation of 1.06-μm lasers in this temperature range.
Thin-film beam splitter and reflector for optical guided waves
Authors: Tsang Won-Tien , Wang Shyh
Published: February 2003

We report the fabrication and operation of a new and simple beam splitter and reflector for thin-film optical guided waves.
Amplification of multiline/multiband CO2 laser pulses
Authors: Figueira J. F. , Ladish J. S. , Schappert G. T. , Thomas S. J.
Published: February 2003

Amplification measurements of single-line and multiline/multiband nanosecond CO2 laser pulses are reported. It is shown that at amplifier pressures of 600 Torr the saturation energy for multiline pulses is twice as large as for single-line pulses.
Vibration-vibration pumping of carbon monoxide initiated by an optical source
Authors: Rich J. W. , Bergman R. C. , Raymonda J. W.
Published: February 2003

A steady-state nonequilibrium population distribution of the vibrational states of carbon monoxide has been produced by optical pumping. A supersonic flow CO laser was used to excite a flowing mixture of CO which is pressure broadened by argon. A V-V pumped nonequilibrium distribution was measured over the first 30 vibrational states of CO.
Improved cw laser action on the 118.6- and 220-μm H20 transitions using helium and hydrogen
Authors: Woskoboinikow P. , Jennings W. C.
Published: February 2003

The power of a cw water-vapor laser operating on the far-infrared transitions of 118.6 and 220 μm has been considerably improved by the use of helium and hydrogen gas additives. The laser power on the 118.6-μm transition has been increased by an order of magnitude from 1.5 to 15 mW in a nonoptimized cavity. For the same discharge current of 1.8 A, the power on the 220-μm line has been increased from 0.26 to 1.3 mW.
Mode locking of a He-Ne 3.39-μm laser using strong internal phase modulation
Authors: Konishi Satoshi , Kobayashi Tetsuro , Sueta Tadasi
Published: February 2003

The possibility of generating ultrashort optical pulses from narrow-linewidth lasers by means of mode locking is discussed. An experiment using a He-Ne 3.39-μm laser and applying strong intracavity phase (FM) modulation of 580 MHz was performed to demonstrate the possibility. The oscillation bandwidth was observed to be increased over a frequency range of 7 GHz. The pulsewidth estimated from the power spectrum was about 170 ps, while the reciprocal of the linewidth was about 3 ns.
Polarization effects in holographic multiplexing
Authors: Okayama Hiroshi
Published: February 2003

The polarization characteristics of holograms multiplexed with the object beam of an E mode and with that of an H mode are compared. Holographic multiplexing is carried out by the technique of the Fourier transform hologram using a mask of the sector type. The characteristics obtained are evaluated by measurements of diffraction efficiencies. It is found that the diffraction efficiencies of holograms are improved by about 26.9% by changing the polarization mode of an object beam at the second exposure.
LiNdP4O12 laser pumped with an AlxGa1−xAs electroluminescent diode
Authors: Saruwatari Masatoshi , Kimura Tatsuya , Yamada Tomoaki , Nakano Jun’ichi
Published: February 2003

Using an incoherent AlxGa1−xAs light-emitting diode (LED) as a pump source, pulsed laser oscillation was observed in a 300-μm-thick LiNdP4O12 crystal cooled to −35 °C. The oscillation threshold power density is 8.2 W/cm2 for the LED pump, and is compared with that for an Ar laser pump and theoretical values. The temperature dependence of oscillation threshold and optical round-trip loss are discussed.
Controlled picosecond gating and amplification of ultrafast optical signals
Authors: Olson G. L. , Busch G. E.
Published: February 2003

A positively gated ultrafast amplifying shutter is described. The population inversion created by the action of an intense picosecond pulse in a saturable absorbing dye provides the means for high gain amplification of optical signals. The introduction of a second pulse at a wavelength within the emission band of the dye rapidly depletes the inversion and thus terminates the gain. Gated amplifier gains from 50 to 100 are reported and control of delays between the pulses allows shutter aperture times to be reproducibly varied from ∼12 to ≳60 psec.
Tunable distributed-feedback dye laser
Authors: Aoyagi Yoshinobu , Aoyagi Takashi , Toyoda Koichi , Namba Susumu
Published: February 2003

A tuning range of more than 160 Å was obtained in a rhodamine 6G distributed-feedback laser by using a mechanical tuning method. An electromechanical tuning of about 10 Å was also obtained.
Electron transport at high fields in a-SiO2
Authors: Ferry D. K.
Published: February 2003

An iterative-integral technique is used to determine the velocity of hot electrons in a-SiO2. Deviations from linearity begin for fields above 8×105 V/cm, and saturation of the velocity-field curve sets in for fields above 1×106 V/cm.
Photocurrent suppression in heterojunction solar cells
Authors: Anderson R. L.
Published: February 2003

A thin insulating layer at the material interface of a heterojunction solar cell can cause a suppression of photocurrent. This photocurrent suppression increases with increasing illumination intensity and interfacial layer thickness. Although the presence of such an interfacial layer can increase the conversion efficiency of solar cells at low illumination intensities, the photocurrent suppression effect precludes its use in systems using appreciable solar concentration.
Mechanism of electrochromism in WO3
Authors: Hersh H. N. , Kramer W. E. , McGee J. H.
Published: February 2003

X-ray photoelectron spectra of colored WO3 films, thermodynamic analysis of galvanic behavior of the tungstic oxide cathode, plus other new lines of evidence, clearly establish the previously uncertain mechanism of the electro-optic effect in amorphous WO3, viz., a simultaneous injection of electrons and positive ions into a film via an electrochemical process, with the consequent development of a low-x tungsten bronze. The positive ion, in both the films and in tungsten bronzes, remains fully ionized even in the presence of high densities of injected electrons.
ZnS blue-light-emitting diodes with an external quantum efficiency of 5×10−4
Authors: Katayama Hirohiko , Oda Shunri , Kukimoto Hiroshi
Published: February 2003

ZnS diodes emitting a stable and bright blue light with forward biases above 5 V are investigated. The external quantum efficiency for the diode is as high as 5×10−4 at room temperature. The presence of a thin high-resistivity ZnS layer on the low-resistivity ZnS is essential for the present diode. The fairly high efficiency is accounted for by a relevant mechanism of the donor-acceptor–pair emission.
Very low-threshold double-heterojunction AlxGa1−xAs injection lasers
Authors: Ettenberg M.
Published: February 2003

Double-heterojunction AlxGa1−xAs lasers have been prepared with a compositional discontinuity Δx at the heterojunctions of 0.45–0.68 and active region widths of ∼0.1 μm. These devices have the lowest room-temperature threshold current densities (475 A/cm2) yet reported, with a differential quantum efficiency of 40% or more.
Output flux instabilities in a flowing-gas cw CO2 electric discharge laser
Authors: Yoder M. J. , Ahouse D. R.
Published: February 2003

Temporal measurements of laser output flux of a flowing-gas cw CO2 electron-beam-sustainer electric discharge laser exhibit large fluctuations. The amplitude of the fluctuations varies from 20 to 100% depending on cavity pressure, unstable resonator output coupling, and discharge specific power loading. Sharp discontinuities are observed in the laser medium when output flux is extracted. Gain measurements made simultaneously with output flux extraction show large fluctuations both above and below cavity threshold. These results are consistent with a basic self-oscillation instability mechanism proposed for fast-flow cw lasers using unstable resonators.
p-n junction zinc sulfo-selenide and zinc selenide light-emitting diodes
Authors: Robinson Robert J. , Kun Zoltan K.
Published: February 2003

The wide-band-gap group II–group VI compound semiconductors have long been valued for their luminous efficiency, and an obvious application would be p-n junction LED’s. However, these materials could only be made n type, not p type. Using an uncustomary technique, we have succeeded in making stable low-resistivity p-type ZnSxSe1−x and ZnSe by diffusion into n-type substrates, and thereby have made low-resistance LED’s. The diffusion process is carried out in two steps: a deposition step followed by a drive-in. Gallium, indium, and thallium are used to make the material p type. (i) The group IIIA element is present in doping quantities only. (ii) p-type mobility values are presented as a function of hole concentration; temperature dependence establishes that the level is shallow. (iii) The LED’s have low resistance and the light output is linear with current above the barrier voltage. (iv) Generation current from the junction, n=2, is observed below the barrier voltage. External quantum efficiencies around 1% are estimated with optimized diodes.
Fast infrared optical shutter
Authors: Nurmikko A. V. , Pratt G. W.
Published: February 2003

Rapid modulation of infrared radiation in the 10-μ wavelength region has been achieved by operating a thin-film Pb1−xSnxTe optical shutter. The switching mechanism considered here takes advantage of the rapid absorption edge shift induced by an intense incident optical pump. Experimental evidence suggests the possibility of producing picosecond infrared transients.
Photoconductive probing of acoustoelectric domains with application to optical image scanning
Authors: Celler G. K. , Bray Ralph
Published: February 2003

A simple new method is described for probing acoustoelectric domains in n-GaAs through their strong photoconductive response to a focused light beam. This permits a scan of the spatial distribution and propagation of the amplified acoustic flux in the sample. As a further application of the photoconductive response, a narrow propagating domain can be used to reveal an optical image projected onto the sample. The techniques are illustrated here primarily for extrinsic photoexcitation with Nd:YAG laser light.
Relativistic space-charge flow in a magnetic field
Authors: Bergeron Kenneth D. , Poukey J. W.
Published: February 2003

An analytic model for space-charge-limited flow in relativistic diodes is presented which includes the effect of a transverse magnetic field below the critical field for magnetic insulation. Conditions for the validity of the model are investigated and comparison is made with recent experiments by Golden et al.
CeP5O14, a new ultrafast scintillator
Authors: Bimberg D. , Robbins D. J. , Wight D. R. , Jeser J. P.
Published: February 2003

CeP5O14 exhibits one emission band in the wavelength range 200–750 μm under cathode ray excitation. This band peaks at 335 nm and decays initially with τ1=12 nsec. A somewhat slower decay with τ2=36 nsec follows. These properties make the material suitable for fast scintillator applications, especially as a beam-indexing phosphor in color cathode ray tubes.
Granular metal-semiconductor vidicon
Authors: Wronski C. R. , Abeles B. , Rose A.
Published: February 2003

A novel low-dark-current high-sensitivity vidicon target has been made using a semiconductor ‘n-type CdSe’ coated with a granular metal ‘Au-SiO2’ film. The granular metal-semiconductor interface forms a Schottky barrier which blocks effectively the beam electrons. The high lateral resistance of the granular metal film precludes the need of an array structure to achieve good resolution.
Magnetically tunable laser emission from [Hg,Cd]Te
Authors: Weber B. A. , Sattler J. P. , Nemarich J.
Published: February 2003

Tunable spin-flip Raman and recombination laser emission from [Hg,Cd]Te have been observed using a chopped-cw CO2 laser as the pump. Peak powers of over 1 mW and average powers of over 100 μW have been obtained for both the spin-flip Raman and recombination emissions with conversion efficiencies of over 0.3%. A zero-field g factor of ‖82‖±3 has been measured, corresponding to a conduction band-edge effective-mass ratio of 0.0098±0.0004.
Evaporative degradation of HgI2 x-ray detectors
Authors: Scott Ronald S. , Fredericks George E.
Published: February 2003

The instability of unprotected HgI2 x-ray detectors in vacuum, contrasted with their apparent stability in air is examined. The degradation is treated as a result of noncongruent sublimation of Hg and I2 from the detector surface, resulting in a buildup of free Hg atoms. The calculations indicate that the observed degradation of these devices in vacuum is to be expected, and that similar degradation in air will occur at rates 103–104 times more slowly.
Transition waveguides for coupling fibers to semiconductor lasers
Authors: Dalgoutte David G. , Mitchell Gordon L. , Matsumoto Roger L. K. , Scott William D.
Published: February 2003

The geometric mismatch between semiconductor lasers and single-mode optical fibers or diffused waveguides causes serious light loss. Transition fibers with cores that change shape from rectangular to circular can be used to reduce these losses. Techniques for fabrication of transition fibers with losses of 1 dB are discussed.
Infrared holograms recorded in high-resolution photographic plates with the Herschel reversal
Authors: Graube Andrejs
Published: February 2003

High-resolution holograms have been produced with 1.06-μm radiation in photographic plates by utilizing the Herschel reversal effect. Diffraction efficiencies of 25% have been achieved with red light reconstruction, and the spatial frequency response exceeds 1300 cycles/mm. The H and D curve for Herschel reversal in Kodak 120−01 plates is presented.
Nitrogen-silicon reaction and its influence on the dielectric strength of thermal silicon dioxide
Authors: Vromen B. H.
Published: February 2003

Exposure of silicon to a nitrogen ambient at 1050 °C either before or after oxidation can adversely affect the dielectric strength of thermal oxides. An exposure of 20–30 min and a nitrogen concentration of about 0.1 at% in the silicon can produce such effects. The damaged layer extends for more than 0.13 μm inside the exposed silicon.
Comment on ’’Current noise measurements in continuous metal thin films’’
Authors: Hooge F. N. , Kleinpenning T. G. M.
Published: February 2003

Celasco and Fiorillo did not detect 1/f noise in aluminum films. This has no physical significance since the current densities they used are too low for 1/f noise to be detectable.
Reply to ’’Comment on ’Current noise measurements in continuous metal thin films’ ’’
Authors: Celasco M. , Fiorillo F.
Published: February 2003

The results of our investigation on current noise in aluminum films are pointed out. They were not intended as a check of Hooge and Hoppenbrouwers’s theory.
Subnanosecond microscopic holographic interferometry of plasmas produced by 1-nsec CO2 laser pulses
Authors: Fedosejevs R. , Richardson M. C.
Published: February 2003

Two-dimensional distributions of the electron density within plasmas produced by 1-nsec-duration high-intensity (≳1013 W/cm2) CO2 laser pulses on solid polyethylene targets have been obtained with the aid of microscopic holograhphic interferometry. Short 700-psec pulses, derived from a synchronized ruby laser, were used to illuminate the interferometric system, which had a spatial resolution of ∼10 μ.
Determination of semiconductor surface properties using surface acoustic waves
Authors: Das P. , Motamedi M. E. , Webster R. T.
Published: February 2003

Surface properties of semiconductors may be determined by measuring the change in attenuation constant, acoustoelectric voltage, and convolution output of a semiconductor on a lithium niobate acoustic surface wave convolver structure. The change is caused by the application of a dc pulse voltage. Experimental results are presented for both p- and n-type silicon. The method is contactless, sensitive, and requires no sample preparation except polishing of one side. Also it is possible to study the variations of the semiconductor surface states along the direction of propagation of the surface wave by proper modification of this method.
Novel metal-clad optical components and method of isolating high-index substrates for forming integrated optical circuits
Authors: Tien P. K. , Martin R. J. , Riva-Sanseverino S.
Published: February 2003

One of the difficulties in integrated optics is to form passive and active devices of different materials on a common substrate. We have solved part of the difficulty by introducing a technique of isolating low-index devices from a high-index substrate. We also report novel metal-clad optical components which can be formed on any substrate.
Domain wall velocity in orthoferrites
Authors: Konishi S. , Miyama T. , Ikeda K.
Published: February 2003

The domain wall velocity in YFeO3 and TbFeO3 single-crystal platelets is measured by the bubble-collapse method. Though weak knees like saturation occur at 4800, 8000, and 14 000 m/sec, the wall velocity in YFeO3 increases nearly linearly with increasing drive field up to 25 000 m/sec at a drive field of 370 Oe. The velocity in TbFeO3 increases linearly up to 3000 m/sec (600 Oe). A mechanism quite different from that in garnet films appears to be operative in orthoferrites.
Pressure measurements very near an electrical arc discharge in a liquid using a lithium niobate piezoelectric transducer
Authors: Huff C. F. , Graham R. A.
Published: February 2003

The pressure pulse generated by an electric arc discharge in aqueous liquids was measured with a lithium niobate piezoelectric transducer. These measurements are the first time-resolved pressure pulses recorded in proximity to an arc channel.
Electron diffraction from areas less than 3 nm in diameter
Authors: Geiss R. H.
Published: February 2003

A method of obtaining rocking-beam microarea electron diffraction patterns is described employing the electron optics of a single-field condenser-objective lens in a commercial scanning transmission electron microscope. Theoretical and experimental evidence is presented showing that it is possible to obtain diffraction patterns from areas less than 3 nm in diameter with minimum lattice spacings of 0.14 nm. This is demonstrated with a specimen consisting of small gold particles evaporated on a carbon substrate.
Zinc oxide–silicon monolithic acoustic surface wave optical image scanner
Authors: Elliott J. K. , Gunshor R. L. , Pierret R. F. , Davis K. L.
Published: February 2003

An optical image is converted into an electrical signal by utilizing acoustic surface wave convolution in a monolithic structure composed of a piezoelectric zinc oxide film on a silicon substrate. Measurements are presented describing the variation of convolution efficiency with light intensity, input acoustic power, and convolver gate electrode dc bias. An initialization procedure is described that allows the device to operate either in an image memory mode or in a nonstorage mode which permits scanning of nonstationary images.
Conductivity of ionized flowing gases
Authors: Lee J. J.
Published: February 2003

In a previous paper, the electron distribution function for a weakly ionized flowing gas in an electric field has been derived. The distribution function is used to calculate the conductivity of the flow. First, the gas molecules are considered as hard spheres. The resulting formula is identical in form to that obtained by Margenau, except that a correction term due to the flow speed is included in the temperature. Next, the gas is treated as Maxwell molecules. In this case, when the field is perpendicular to the flow, the expression reduces to the familiar form ne2/m (ν+iω), independent of the temperature and the flow speed.