bluuebunny/crossref_metadata_2025 huggingface dataset:
PASSIVE Q-SWITCHING OF A N2O LASER USING ETHYLENE
Authors: Brunet Henri , Voignier François
Published: January 2004

Passive Q-switching of a N2O laser operating on the P(19) line at 922.37 cm−1 has been achieved using ethylene as the saturable absorber. Use of a grating together with an iris eliminates spurious oscillations on the other laser lines.
OPTICAL THIRD HARMONIC MEASUREMENTS OF SUBPICOSECOND LIGHT PULSES
Authors: Eckardt R. C. , Lee C. H.
Published: January 2004

A new technique for measurement of picosecond light pulses is described using the unique polarization properties of optical third harmonic generation. A width of half-maximum intensity less than 0.73 psec is observed for a mode-locked neodymium glass laser.
AN EFFECT OF A HIGH MAGNETIC FIELD ON THE EMISSION SPECTRUM OF XENON PLASMA
Authors: Laiho R. , Mäntysalo E.
Published: January 2004

An increase in the continuum emission of light from xenon plasma in a high magnetic field is reported.
ABSORPTION FROM EXCITED STATES IN LASER-PUMPED CALCIUM
Authors: McIlrath T. J.
Published: January 2004

The narrowed output of a tunable dye laser has been used to populate metastable levels 2 eV above the ground state in atomic calcium. Absorption spectra from the excited level were recorded by use of a fast flashlamp continuum.
HOLOGRAMS IN THIN BISMUTH FILMS
Authors: Amodei J. J. , Mezrich R. S.
Published: January 2004

Holograms with better than 6% efficiencies and resolutions close to 1000 lines/mm were achieved on Bi films with good linearity and reasonable sensitivity.
COMMENTS ON MATERIALS FOR EFFICIENT INFRARED CONVERSION
Authors: Johnson L. F. , Geusic J. E. , Guggenheim H. J. , Kushida T. , Singh S. , Van Uitert L. G.
Published: January 2004

The mechanisms relating to infrared-pumped visible and ultraviolet emission observed from Yb3+–Er3+ and Yb3+–Ho3+ ions in BaYF5 and Y3OCl7 (reported in the companion papers) are discussed. An analysis is given of the material parameters required for efficient conversion and the limiting performance which can be expected from a near ideal material is indicated.
PHOTOCONDUCTIVITY STUDY OF DIVACANCY FORMATION IN NEUTRON-IRRADIATED Si
Authors: Stein H. J.
Published: January 2004

Photoconductivity measurements between 1.2 and 5 μ have been used to study the annealing characteristics of defects in p-type silicon following neutron irradiation at 82°K. In particular, the 3.9 μ photoconductivity peak previously associated with the presence of divacancies in irradiated silicon has been investigated. The magnitude of the 3.9 μ peak is found to be small after neutron irradiation at 82°K, but it increases markedly during subsequent annealing between 175 and 375°K. The annealing growth of the 3.9 μ (divacancy) peak between 275 and 375°K is similar to vacancy-oxygen center growth previously observed following neutron irradiation ∼225°K. The divacancy growth is attributed to vacancy liberation from neutron produced defect clusters in accord with the previous interpretation of vacancy-oxygen center growth. The annealing lots of the 3.9 μ peak between 375 and 550°K is correlated with the annealing of divancies as measured by optical absorption after room-temperature neutron irradiation.
TEMPERATURE DEPENDENCE OF THE MAGNETIC SUSCEPTIBILITY OF LIQUID Au–Co AND Co–B ALLOYS
Authors: Menth A. , Bagley B. G.
Published: January 2004

The magnetic susceptibilities of liquid Au–Co and Co–B alloys were studied in order to obtain information concerning possible ferromagnetic behavior in the liquid state. We did not observe ferromagnetism; only Curie-Weiss-like behavior. No divergence of the magnetic susceptibility in the liquid phase is observed.
WAVELENGTH DEPENDENCE OF LASER-INDUCED GAS BREAKDOWN USING DYE LASERS
Authors: Alcock A. J. , DeMichelis C. , Richardson M. C.
Published: January 2004

Two tunable dye lasers, operating in the region 7000 to 8500 Å, have been used to study the wavelength dependence of laser-induced gas breakdown. The results confirm the existence of a threshold maximum for argon and xenon, and indicate that the shape and location of the peak depend on the gas investigated.
FIELD-ENHANCED EMISSION AND CONSTANT-FIELD DOMAINS IN SEMICONDUCTORS WITH DEEP TRAPS
Authors: Panousis P. T. , Krambeck R. H. , Johnson W. C.
Published: January 2004

Evidence is presented which indicates that electron and hole emission from the acceptor level in gold-compensated n-type silicon is enhanced by electric fields and that this effect can account for the disparity between various measurements of emission rates. The effect can also lead to the formation of neutral high-field domains.
EPITAXY MODIFICATIONS TO EVAPORATED fcc METALS INDUCED BY ELECTRON BOMBARDMENT OF ALKALI HALIDE SUBSTRATES
Authors: Stirland D. J.
Published: January 2004

Recent experiments concerned with the orientations of evaporated fcc metals on alkali halide cleavage surfaces have shown that low-energy electron bombardment of the surfaces during deposition can modify the orientations. Specifically for the case of Au on NaCl or KCl, it is possible to produce deposits in the parallel orientation (epitaxy). Observations by LEED, Auger emission spectroscopy, and mass spectrometry suggests that the electron bombardment produces surface defects, probably Cl− vacancies. The nucleation of five-atom clusters at such defects has been considered for various alkali halides, and the relevance to the general problem of epitaxy is discussed.
KILOWATT CO2 GAS-TRANSPORT LASER
Authors: Tiffany William B. , Targ Russell , Foster J. D.
Published: January 2004

Closed-cycle gas cooling techniques have resulted in a self-contained cw kW CO2 laser having a 1-m active length. The CO2, N2, He gas mixture is recirculated through a heat exchanger following forced convection transverse to the optical cavity and the electrical discharge. Output power has been measured as a function of flow velocity and electrical input power.
FIELD DEPENDENCE OF RECOMBINATION RADIATION FROM BULK-IONIZED SEMICONDUCTORS
Authors: Southgate P. D.
Published: January 2004

Fields from several hundred to 2000 V cm−1 have been found to reduce the recombination radiation intensity from bulk-ionized GaAs and InP and to shift the spectrum to lower energies. The effect is believed to be due to changes of self-absorption caused by heating of the degenerate electron distribution.
QUENCHING OF HELIUM AFTERGLOW BY INFRARED PHOTONS
Authors: Kaplafka J. P. , Merkelo H. , Goldstein L.
Published: January 2004

The visible afterglow radiation from low-pressure weakly ionized helium exhibits a partial quenching due to absorption of infrared photons (0.11–0.14 eV). The helium sample is placed in the cavity of a Q-switched CO2 laser and studied at gas temperatures in the range from 77 to 300°K. The partial quenching appears to originate from photon-induced change of population of a state or states of a neutral or ionic helium molecule.
ION-BOMBARDMENT-ENHANCED ETCHING OF SILICON
Authors: Gibbons J. F. , Hechtl E. O. , Tsurushima T.
Published: January 2004

A method is described which permits rapid and precise selective etching of silicon crystal surfaces without protecting any part of the surface during the etch procedure. Prior to the etching process the areas to be etched are subjected to an ion-bombardment treatment, which increases the etch rate in the bombarded surface layer compared to the etch rate of untreated silicon. Etching characteristics for silicon crystals bombarded with neon and argon are presented and shown to agree with theoretical predictions based on a simple model in which the etching characteristics are related to implantation-produced cluster damage.
INFRARED HOLOGRAPHY AT 10.6μm
Authors: Chivian Jay S. , Claytor R. N. , Eden D. D.
Published: January 2004

Infrared holography at 10.6 μm has been accomplished by using a thermochromic material, cuprous mercuric iodide, to record an on-axis interference pattern. The pattern is subsequently reduced in a two-step photographic process, and reconstruction is accomplished in the visible with He–Ne laser light.
REPETITIVELY PUMPED OPTICAL PARAMETRIC OSCILLATOR AT 2.13 μ
Authors: Ammann E. O. , Oshman M. K. , Foster J. D. , Yarborough J. M.
Published: January 2004

The operation of an optical parametric oscillator which is directly pumped by the 1.06-μ output of a continuously pumped, repetitively Q-switched Nd:YAG laser is described. The oscillator uses a 3-mm lithium niobate crystal in a non−90° orientation as the nonlinear material. 17 mW of average output power at 2 μ have been obtained giving an oscillator conversion efficiency of 8%. Measurements are also reported of pump power threshold, pump depletion, and wavelength tuning of the oscillator. No optically induced index inhomogeneities were observed in the lithium niobate.
NEW HIGH-DISPERSION HIGH-RESOLUTION X-RAY SPECTROMETER
Authors: Schnopper H. W. , Kalata K.
Published: January 2004

A high-efficiency, high-resolution, high-dispersion, low-cost x-ray spectrometer is described. Although the instrument was developed primarily for space-science applications, it has a broad range of application for normal laboratory research problems. As an example of its performance, measurements of the CrKα1,2 spectrum are presented. The observed, uncorrected full-widths at half-maximum intensity are Kα1 = 2.09 eV and Kα2 = 2.67 eV. Fine structure details, hitherto unreported, were also observed.
A cw RING-CAVITY PARAMETRIC OSCILLATOR
Authors: Byer R. L. , Kovrigin A. , Young J. F.
Published: January 2004

A cw visible ring-cavity parametric oscillator has been constructed and pump depletions of 60% have been observed. The experiment verified the increased conversion efficiency predicted for a parametric oscillator operating without a back-generated pump wave, and also showed the improved stability which can result from the optical isolation provided by the ring-cavity configuration.
IMPROVEMENTS OF REVERSE I–V CHARACTERISTICS IN EPITAXIAL PLANAR SCHOTTKY BARRIER DIODES
Authors: Kano Gota , Fujiwara Shohei , Iizuka Matsuo , Hasegawa Hiromasa , Sawaki Tsukasa
Published: January 2004

Edge leakage effects in Mo–Si epitaxial planar Schottky barrier diodes have been studied and a simple method for eliminating this effect has been proposed. Improved reverse I–V characteristics have approached the theoretical limit.
THERMAL EMISSION RATES OF CARRIERS AT GOLD CENTERS IN SILICON
Authors: Sah C. T. , Forbes L. , Rosier L. I. , Tasch A. F. , Tole A. B.
Published: January 2004

Thermal emission rates of electrons and holes at the gold-acceptor center (EC − EAu− = 550 mV) and of holes at the gold-donor center (EAu+ − EV = 350 mV) are measured using the dark current, dark capacitance, and photocapacitance transient methods. About ten decades of the electron emission rate and eight decades of the hole emission rates are obtained in the temperature range of −160 to +100°C. The data correspond to electric fields of 104 and 105 V/cm maximum field in the p-n junction and differ from the thermal equilibrium emission rates computed from previously published capture rate data at thermal equilibrium due to the field dependence of the capture rate from hot electron effect and of the emission rate from barrier lowering of the impurity potential.
SPACE-CHARGE INJECTION: A NEW TECHNIQUE FOR STUDYING NONUNIFORM FIELD BREAKDOWN PHENOMENA
Authors: Klewe R. C. , Quigley M. B. C. , Tozer B. A.
Published: January 2004

The pulse of a Q-switched ruby laser operated below the threshold for spark formation and focused in a point-plane gap can profoundly affect the development of impulse corona for times up to 1 sec. This effect can be strongly modified by the application of a small (10 V/mm) dc field across the gap. With a positive impulse to the point and a negative dc field, a change of 10 μsec in the delay time between charge injection and application of the voltage impulse can change the probability of gap flash-over from near zero to greater than 90%.
PASSIVE Q-SWITCHING OF THE CO2 LASER BY CH3F AND PF5 GASES
Authors: Chang T. Y. , Wang C. H. , Cheo P. K.
Published: January 2004

The CH3F gas is found to cause passive Q-switching of two CO2 laser lines in the 9.6 μ band. The responsible vibrational-rotational transitions of CH3F are identified. The PF5 gas is found to have an unusual capability of Q-switching practically all the P-branch laser lines in the 10.6 μ band of CO2. Relevant absorption coefficients are presented.
OPTICAL LIMITING IN SEMICONDUCTORS
Authors: Ralston J. M. , Chang R. K.
Published: January 2004

The nonlinear absorption coefficients of Si from 146 to 452°K and of CdSe, CdTe, and GaAs at 300°K were measured with a Nd:YAlG Q-switched laser. The reported stepwise nature of nonlinear absorption for Si is confirmed, but the assignment of a three-photon process is uncertain. As an optical limiter, the optimum Si thickness to be inserted within a Nd:laser cavity is discussed.
SUPERRADIANT TRAVELING-WAVE DYE LASER
Authors: Mack M. E.
Published: January 2004

Superradiant traveling-wave laser emission has been observed with several polymethine cyanine dyes pumped by a mode-locked ruby laser. This mode of operation provides a simple and effective means for generating picosecond-duration pulses at a variety of wavelengths.
FREQUENCY CONTROL OF A PULSED OPTICAL PARAMETRIC OSCILLATOR BY RADIATION INJECTION
Authors: Bjorkholm J. E. , Danielmeyer H. G.
Published: January 2004

We have demonstrated a method of accurately controlling the spectral properties of a pulsed, singly resonant optical parametric oscillator. The resonated output of a ruby-laser-pumped LiNbO3 oscillator was ``locked'' to the frequency of radiation injected into a mode of the oscillator cavity by a single-frequency cw Nd:YAG laser. Locking could be obtained if the peak of the oscillator gain curve was tuned to within 18 Å of the YAG wavelength. The minimum injected power required to ensure locking of the 100-kW oscillator output was 1 μW.
ULTRASONIC IMAGING OF INTERNAL STRUCTURE BY BRAGG DIFFRACTION
Authors: Landry John , Powers John , Wade Glen
Published: January 2004

Results of experiments are described in which the technique of ultrasonic imaging by Bragg diffraction was used to observe internal detail in an aluminum plate and in a tropical fish. In addition, the extension of the Bragg technique to reflection and dark-field imaging is described.
INFRARED HOLOGRAPHY WITH ORGANIC PHOTOCHROMIC FILMS
Authors: Izawa Tatsuo , Kamiyama Masahide
Published: January 2004

A hologram is made by a CO2–N2–He laser utilizing the thermal bleaching of organic photochromic films and is reconstructed by a 6328 Å He–Ne laser beam. These films are made of photochromic spiropirans dissolved into plastics.
FREQUENCY PULLING AND PULSE POSITION MODULATION OF PULSING cw GaAs INJECTION LASERS
Authors: Ripper José E. , Paoli Thomas L.
Published: January 2004

The frequency pulling and locking of intensity pulsations from continuously operating GaAs injection lasers have been studied by varying the frequency of the externally applied locking signal in the vicinity of the self-induced pulse rate or one of its harmonics. The ability of the laser pulse rate to follow a rapidly varying locking signal has led to the first realization of optical pulse position modulation with microwave repetition rates. Modulation rates attainable with this effect are expected to be as high as one-half the self-induced pulse rate.
ELECTRON PARAMAGNETIC RESONANCE OF DEFECTS IN ION-IMPLANTED SILICON
Authors: Brower K. L. , Vook F. L. , Borders J. A.
Published: January 2004

The first EPR measurements of the identity of defects in an ion-implanted layer (< 15 000 Å) are reported. The Si–P3 center is the dominant paramagnetic defect produced at room temperature by 400-keV O+ implantation in Al- and B-doped Lopex Si, and it anneals below 200°C. The Si–P1 center is the dominant defect remaining above 200°C, and it anneals near 350°C. Interstitial Al++ (Si–G18) are observed in the Al-doped sample; their number indicate that Si interstitials do not migrate over large distances into the unirradiated Si. Comparison of EPR and infrared data indicates that the Si divacancy is produced in the diamagnetic neutral charge state.
ELECTRICAL CONTROL OF HOLOGRAPHIC STORAGE IN STRONTIUM-BARIUM NIOBATE
Authors: Thaxter J. B.
Published: January 2004

Single-crystal Sr0.75Ba0.25Nb2O6 when used in conjunction with an externally applied electric field is shown to be a sensitive volume holographic medium capable of high-resolution information storage. Optically induced refractive index changes of 5 × 10−4 have been observed with laser exposure of 14 J/cm2. A simple relation between the applied electric field and optical exposure is determined which allows electrical control of optically induced refractive index change. In addition to control of the optically induced effect it is found that the applied electric field can also be used to control the diffraction efficiency of the holographic reconstruction process.
TWO SATURABLE ABSORBERS FOR EXTENDING THE WAVELENGTH LIMITS OF A PASSIVELY Q-SWITCHED CO2 LASER
Authors: Marcus S.
Published: January 2004

The discovery of two new passive Q-switching agents for use in the CO2 laser is reported. These gases, chlorotrifluoroethylene and difluorodichloromethane, permit extension of the range of wavelengths over which the passively Q-switched CO2 laser can be operated. Saturation intensities and small signal absorption coefficients were measured for these gases.
DESIGN OF A MAGNETIC SPECTROMETER FOR PHOTOELECTRON SPECTROSCOPY
Authors: Fadley C. S. , Miner C. E. , Hollander J. M.
Published: January 2004

We present the results of a computer design study for an iron-free double-focusing magnetic spectrometer specifically intended for photoelectron spectroscopy. With single detector operation the proposed design is more efficient than any existing magnetic double-focusing spectrometer, and the focal-plane characteristics allow more than a 100-fold increase in data accumulation rate with a multichannel detector. This design also has very high physical accessibility near the source and detector areas and it is compatible with either normal or ultrahigh vacuum operation.
IMAGING BY CORRELATION OF INTENSITY FLUCTUATIONS
Authors: Beard Terry D.
Published: January 2004

A new way of obtaining images of complex incoherently illuminated subjects is demonstrated. A correlation interferometer measures and records the square of the modulus of the two-dimensional coherence function of a thermally illuminated object and a displaced reference point source. The Fourier transform of this correlation function contains an inverted and uninverted image of the subject.
GaP RED ELECTROLUMINESCENT DIODES WITH AN EXTERNAL QUANTUM EFFICIENCY OF 7%
Authors: Saul R. H. , Armstrong J. , Hackett W.H.
Published: January 2004

External quantum efficiencies η as high as 7.2% have been obtained for gallium phosphide red light emitting diodes. The p-n junctions were prepared using a p-on-n liquid phase epitaxy process in which the dopant levels significantly differ from those previously reported. Doping profiles for these junctions are compared with earlier n-on-p structures (η = 1–2%) and it is suggested that the observed high efficiencies result from (1) more efficient electron injection, (2) increased O concentration in the p-type layers which may result in a higher concentration of Zn–O complexes, and/or (3) fewer free holes in the p region contributing to nonradiative recombination.
REVERSIBLE HILLOCK GROWTH IN THIN FILMS
Authors: Lahiri S. K. , Wells O. C.
Published: January 2004

Thin films of lead and aluminum on substrates of lower thermal expansion coefficient were examined using a hot stage in a scanning electron microscope. Hillocks were seen to grow as the temperature was increased and then to shrink as the temperature slowly fell. This effect is thought to be caused by a change from compressive into tensile stress in the film.
GUNN EFFECT IN n-TYPE InSb
Authors: Smith John E. , Nathan Marshall I. , McGroddy James C. , Porowski Sylwester A. , Paul William
Published: January 2004

In this letter we report the observation of the Gunn effect in n-type InSb at 77°K and atmospheric pressure. This result is surprising, since it was previously thought that the large amount of carrier multiplication at fields below the Gunn threshold would preclude observation of the Gunn effect in InSb and similar materials. Several explanations for the negative differential conductivity underlying the Gunn effect in this case are possible, but the intervalley transfer mechanism is most consistent with the observed negative pressure coefficient of the threshold field.
PHOTOMIXING AT 10.6μ WITH STRONTIUM BARIUM NIOBATE PYROELECTRIC DETECTORS
Authors: Abrams R. L. , Glass A. M.
Published: January 2004

Theoretical limitations of optical heterodyne detection with pyroelectric detectors are discussed. It is shown that the minimum detectable power Pm of Sr1−xBaxNb2O6 pyroelectric detectors at 10.6μ, with an intermediate frequency of 1 MHz and a local oscillator power PL = 1 W is Pm = 8×10−16 W/Hz. An experimental heterodyne receiver with the above conditions is shown to have a value Pm = 1.5×10−11 W/Hz where amplifier noise is much larger than detector noise. The theoretical and experimental dependence of Pm on PL are compared in the amplifier noise limit.
ELECTRON PARAMAGNETIC RESONANCE IN ION IMPLANTED SILICON
Authors: Daly D. F. , Pickar K. A.
Published: January 2004

Electron paramagnetic resonance spectra of radiation damage centers in silicon have been observed following implantation with nitrogen and phosphorous ions. Two of these spectra have narrow lines and can be fitted to anisotropic g-tensors and zero field splitting tensors. One is a new spectrum with approximately [111] axial symmetry and will be called the Si-B2 spectrum. The other can be identified as the Si-P3 spectrum which has been known previously to result from neutron irradiation. Both spectra are attributed to defects in the crystal containing broken silicon bonds.
EFFECTS OF DIFFUSION ON THE SATURATION INTENSITY OF A CO2 LASER
Authors: Smith David C. , McCoy John H.
Published: January 2004

The power and gain capabilities of a CO2 laser are dependent upon the saturation intensity of the laser media. Saturation intensities reported in the literature range from 22 to 100 W/cm2 for seemingly similar laser discharge tube bores, currents, gas flow rates, and gas mixtures. Measurements of saturation intensities between 7.5 and 57 W/cm2 in a CO2 laser amplifier indicate that this parameter is inversely related to the radius of the amplified beam. A significant increase in saturation intensity for small beam radii is attributed to diffusion of excited CO2 molecules into the beam. The experimental results are in qualitative agreement with a simplified derivation of a relation governing the saturation intensity which includes molecular diffusion. This effect can result in a serious overestimate of the capabilities of a large beam laser system designed with saturation intensities obtained from small diameter probe beams.
TIME-AVERAGED HOLOGRAPHY WITH TRIANGULAR PHASE MODULATION OF THE REFERENCE WAVE
Authors: Mottier François M.
Published: January 2004

It is shown that the large differences of the peak fringe intensities in the reconstruction of time-averaged holograms may be reduced by synchronous triangular phase modulation of the reference wave. As a by-product, portions of the object vibrating in the same phase are revealed. Optical noise in the reconstruction is low so that the useful amplitude range in vibration analysis is significantly extended by the method described.
DIELECTRIC CONSTANT OF AN ELECTRON-FREE T1+ I− PLASMA
Authors: Davidovits P. , Hirshfield J. L.
Published: January 2004

Measurements are reported of the frequency-dependent complex impedance of a capacitor filled with thallium iodide vapor, photodissociated into T1+ and I− to form an electron-free plasma. Ion concentration and collision frequency are inferred using the cold plasma dielectric constant.
A NEW TYPE OF SURFACE SPIN WAVE IN FERROMAGNETIC FILMS
Authors: De Wames R. E. , Wolfram T.
Published: January 2004

A new type of surface spin wave occurs in a ferromagnetic film with an applied magnetic field perpendicular to the surface when the dipole and exchange energies are comparable. The surface wave propagates parallel to the surface but has a wave vector whose normal component is complex. States having a high degree of localization of the spin wave amplitude near the surfaces can occur.
INTERACTION BETWEEN ELASTIC SURFACE WAVES IN PIEZOELECTRIC MATERIALS
Authors: Svaasand L. O.
Published: January 2004

Nonlinear interaction between elastic surface waves and an almost uniform time-dependent electric field is demonstrated in LiNbO3 at 17 MHz.
GAIN AND SATURATION IN TRANSVERSE FLOWING CO2–N2–He MIXTURES
Authors: Targ Russell , Tiffany William B.
Published: January 2004

Gain and saturation are investigated in a kW CO2–N2–He gas-transport laser. The active medium flows at 35 m/sec transverse to the probe laser beam. Gain falls exponentially downstream of the excitation region with a characteristic decay distance of 7 cm, giving a decay time of approximately 2 msec. A saturation parameter of approximately 250 W cm2 is determined. This large value is due to rapid flow which sweeps the molecules through the laser beam in a time shorter than the upper state relaxation time.
UNIDIRECTIONAL CHANNELING AND BLOCKING: A NEW TECHNIQUE FOR DEFECT STUDIES
Authors: Feldman L. C. , Appleton B. R.
Published: January 2004

This letter reports measurements of a new type of double alignment channeling process which simultaneously uses the ``channeling effect'' and ``blocking effect'' in a relatively simple geometry. Results for the case of 500-keV He ions impinging on ZnO single crystals are shown to be in fair agreement with a calculation of the magnitude of this effect based on the Lindhard model of particle channeling. It is shown that the sensitivity of this measurement to the detection of atoms not on normal lattice sites is a factor of 10–50 greater than in the usual channeling experiment.
TRANSPORT PROPERTIES OF HgCr2Se4 AT FERROMAGNETIC RESONANCE
Authors: Toda Minoru
Published: January 2004

Two new effects have been observed in the transport properties of In-doped HgCr2Se4 at ferromagnetic resonance at 77°K. One is a dc voltage produced in the sample, and the other is a decrease in resistivity. These effects are believed to result from s-d exchange interactions.
DIRECT DEMONSTRATION OF PICOSECOND-PULSE FREQUENCY SWEEP
Authors: Treacy E. B.
Published: January 2004

A direct measurement using time-resolved spectroscopy with response times in the picosecond regime shows that wave groups of different frequencies within an ultrashort pulse generated by a Nd-glass mode-locked laser arrive at a given point at different times. A curve depicting wavelength versus arrival time for a typical pulse is constructed. The frequency sweep is nonlinear and positive across the most intense portion of the spectrum.
TIME-RESOLVED TEMPERATURE MEASUREMENTS IN THE PULSED ARGON ION LASER
Authors: Klein M. B.
Published: January 2004

Time-resolved measurements of the ion and electron temperature in a pulsed ion laser discharge are reported. The data were obtained from spontaneous emission linewidths observed from the end and from the side of the discharge. Significant heating of both ions and electrons during the current pulse was observed. This heating and the resultant decrease in radiation trapping provide a likely explanation for the time behavior of the laser output.
PHOTOEMISSION STUDIES OF INTERFACE BARRIER ENERGIES OF IRRADIATED MOS STRUCTURES
Authors: Peel J. L. , Kjar R. A. , Eden R. C.
Published: January 2004

The effects of ionizing radiation in large geometry MOS structures were studied by use of internal photoemission techniques. Barrier heights at both the silicon-silicon dioxide and the silicon dioxide-metal (chromium) interface were measured before and after irradiation in a Co60 gamma cell. It was determined that the measured barrier energy heights were considerably reduced by radiation-induced oxide charge.
FLUX-FLOW NOISE SPECTRUM IN TYPE II SUPERCONDUCTORS
Authors: Shen S. W.
Published: January 2004

This letter gives experimental verification of Burgess' theory of the flux-flow noise spectrum in Type II superconductors. The measurements made on vanadium foil biased in linear V-I region shows quantative agreement with the modified theory.
IMAGE STORAGE AND OPTICAL READOUT IN A ZnS DEVICE
Authors: Oliver D. S. , Vohl P. , Aldrich R. E. , Behrndt M. E. , Buchan W. R. , Ellis R. C. , Genthe J. E. , Goff J. R. , Hou S. L. , McDaniel G.
Published: January 2004

The operation of an image storage panel, which is read in by means of optical absorption and read out in visible light by means of the Pockels electro-optic effect, has been demonstrated. The sensing, storing, and readout medium consists of a single-crystal film of cubic ZnS coated with a blocking contact. Performance characteristics observed to date on devices with areas between 1 and 2 cm2 are resolution of 85 line pairs/mm, continuous visible readout for 1 h, and image storage for up to 100 h. The readin sensitivity to achieve a 2:1 contrast ratio in readout is 20 erg/cm2.
OPTICAL EXCITATION OF HIGH-AMPLITUDE SURFACE WAVES
Authors: Cachier G.
Published: January 2004

A new scheme for optically exciting high-amplitude Rayleigh waves is described. The interference of two high-power laser beams on a metallic surface produces periodic heating and a Rayleigh wave. The surface motions diffract the two laser beams, and ID∝ IL3. These surface motions were as high as 200 Å at 30 MHz. Rayleigh waves have also been observed at 800 MHz, using a modulated laser for excitation.
STORED CHARGE EFFECTS ON ELECTRON DOSE-DEPTH PROFILES IN INSULATORS
Authors: Harrah L. A.
Published: January 2004

The dose-depth profiles for electrons extracted from a pulsed electron beam machine have been studied using a castable radiation-sensitive plastic. These profiles exhibit a pronounced range shortening at charge fluences greater than 0.5 μC/cm2 which reaches a limiting value, corresponding to a limiting internal field, at fluences greater than 1 μC/cm2. This behavior is interpreted in terms of charge build-up and relaxation by radiation-induced conductivity in the host material, poly(vinyl toluene). Positive charge-trapping additives reduce this conductivity and allow the internal field to build up at lower charge fluences. The ratio of radiation-induced conductivity to dose rate derived from these measurements 1.6 × 10−18 sec/Ω-cm rad compares favorably with the value found at low dose by direct measurement of 3.0 × 10−18 sec/Ω-cm rad.
RADIATION LOSSES IN GLASS OPTICAL WAVEGUIDES
Authors: Kapron F. P. , Keck D. B. , Maurer R. D.
Published: January 2004

Measurements show that single-mode waveguides can be constructed which have radiation losses of about 7 dB/km—very close to the intrinsic material scattering loss. These waveguides, with total losses between 60 and 70 dB/km, have permitted the measurement of bending losses which become dominant at radii of curvature of a few centimeters. An approximate theory based on bending a rectangular guide appears to represent the circular waveguide results very well.
LOCALIZED MODES AND DIVACANCY ABSORPTION IN OXYGEN ION IMPLANTED Si
Authors: Stein H. J. , Beezhold Wendland
Published: January 2004

Optical absorption bands characteristic of localized vibrational modes for both interstitial and substitutional oxygen have been observed in crystalline Si implanted with 220-keV oxygen ions at 300°K. In addition, the fluence dependences for the vibrational modes and also for an electronic transition of the divacancy (1.8-μ band) have been measured. Implanted oxygen ions are found to enhance divacancy formation. This effect was not observed for Sb implantation. The sum of the observed interstitial and substitutional oxygen centers is approximately equal to the number of implanted oxygen ions. An ion fluence 300 times larger than that to detect divacancies was required to detect the vibrational modes of oxygen as expected from the relative production rates and absorption coefficients. At these high fluences the strengths of the vibrational bands increase in magnitude with fluence while the divacancy band decreases. At even higher fluences amorphous layer formation, as indicated by a milky coloration of the surface, caused a decrease in the spacing of optical interference fringes and in the magnitude of the oxygen vibrational bands.
OPTICAL SECOND HARMONIC GENERATION IN FORM OF COHERENT CERENKOV RADIATION FROM A THIN-FILM WAVEGUIDE
Authors: Tien P. K. , Ulrich R. , Martin R. J.
Published: January 2004

We report optical second harmonic generation in form of coherent Cerenkov radiation. The fundamental wave at 1.06 μm propagates in a thin-film optical waveguide which is simply a ZnS film vacuum-deposited on a single-crystal ZnO substrate. The nonlinear polarization excited in the substrate has a phase velocity exceeding that of radiation propagating freely in the substrate material. It thus acts as the source of the observed Cerenkov radiation.
AlxGa1−xAs1−y′P y′–GaAs1−yPy HETEROSTRUCTURE LASER AND LAMP JUNCTIONS
Authors: Burnham R. D. , Holonyak N. , Scifres D. R.
Published: January 2004

A method is described to grow successfully from solution AlxGa1−xAs1−y′P y′ (p-type) on GaAs1−yPy (n-type), to preserve the lattice match (y′ ≈ y), and to obtain the improved heterostructure junction devices previously realized only in the AlGaAs/GaAs system. Although not optimized, these structures have been operated as pulsed room-temperature lasers, and because of an inherent wide-gap window can be used conveniently for optical purposes and for excess carrier lifetime measurements. Carrier lifetime measurements, for example, indicate freedom from defects at the AlGaAsP/GaAsP barrier.
LASER POWER AT 5 μm FROM THE SUPERSONIC EXPANSION OF CARBON MONOXIDE
Authors: McKenzie Robert L.
Published: January 2004

Laser radiation at wavelengths between 4.78 and 5.4μm has been obtained from the supersonic expansion of CO in mixtures of N2 and Ar. The ratio of laser power to the total enthalpy flow rate supplied to the nozzle reservoir was equal to or greater than that obtained from similar CO2 gas-dynamic lasers.
NONLINEAR OPTICAL PROPERTIES OF PERIODIC LAMINAR STRUCTURES
Authors: Bloembergen N. , Sievers A. J.
Published: January 2004

Some novel phase-matching schemes are suggested for nonlinear processes occurring in a composite layered structure of GaP and GaAs.
ELECTRIC AND MAGNETIC RESONANCES OF A PARTICULATE MAGNETOPLASMA: IDENTIFICATION BY MICROWAVE PROPAGATION IN THE VOIGT CONFIGURATION
Authors: Galeener F. L. , Saralkar A. A. , Furdyna J. K.
Published: January 2004

We present a theoretical model for the propagation of plane electromagnetic waves through a discontinuously inhomogeneous magnetoplasma. The model predicts selective excitation of magnetic resonances in the ordinary Voigt configuration and electric resonances in the extraordinary. Measurements of microwave transmission through powdered n-type InSb in an applied magnetic field verify this prediction and establish the character of related resonances previously observed in the Faraday configuration. We conclude that the particle-size-independent resonances of the system are electric dipole in character and thus appear in its effective permittivity, while the size-dependent resonances are magnetic and contribute to the effective permeability. Formulas for effective wave propagation constants are given.
OPTICAL PARAMETRIC OSCILLATION IN LITHIUM IODATE
Authors: Goldberg Lawrence S.
Published: January 2004

Optical parametric oscillation has been achieved in LiIO3 pumped by a pulsed ruby laser, with tunable output to 4μ. Operation of the singly resonant oscillator is described and threshold measurements are compared with theory.
AN EFFICIENT LARGE OPTICAL CAVITY INJECTION LASER
Authors: Lockwood H. F. , Kressel H. , Sommers H. S. , Hawrylo F. Z.
Published: January 2004

A new GaAs injection laser structure is described in which the optical cavity thickness is very large and is varied independently of that of the pair recombination region. Large optical cavities are possible because the radiation propagates predominantly in low-loss n-type material. The problem of catastrophic degradation is greatly reduced because of the lower optical flux density.
APPLICATION OF MICROWAVE HOLOGRAPHY IN THE STUDY OF THE FIELD FROM A RADIATING SOURCE
Authors: Iizuka Keigo , Gregoris Loris G.
Published: January 2004

Microwave holography is applied to the investigation of the radiation mechanism of a monopole. It is shown that a radiating monopole can be described mathematically as two point sources located at each end of the monopole. A microwave hologram was recorded using liquid crystals which upon optical reconstruction yielded two points as predicted by the theory. Using optical techniques, one can visualize the field at the antenna plane, at a plane in the Fresnel zone, and at a plane in the far field. This technique is, however, only one example of microwave holography in the investigation of a radiator. It can be very useful in designing any type of antenna.
MAGNETIC MIRROR PROBE METHOD FOR THE DETERMINATION OF ANISOTROPY OF ELECTRON TEMPERATURE IN A MAGNETIZED PLASMA
Authors: Yamamoto N. , Hatta Y.
Published: January 2004

We propose a magnetic mirror probe method for measurement of the electron temperatures of a magnetized plasma parallel and perpendicular to a magnetic field. The most simple magnetic mirror probe is introduced which is made of ferromagnetic spherical metal.
PREMIXED cw CHEMICAL LASER
Authors: Buczek C. J. , Freiberg R. J. , Hinchen J. J. , Chenausky P. P. , Wayne R. J.
Published: January 2004

cw laser action has been achieved in both HF and DF by employing entirely premixed gases in a cross-field discharge geometry. An electrical discharge, established in the He, SF6, and H2 or D2 mixture upstream and parallel to the optical axis, dissociates the SF6 producing the free fluorine which chemically reacts with the H2 or D2 to produce the excited specie. Output powers up to 0.8 W in HF have been achieved. Operating characteristics, including output power versus gas flow velocity and spectroscopic data, are reported.
ISOTOPE SEPARATION WITH THE cw HYDROGEN FLUORIDE LASER
Authors: Mayer S. W. , Kwok M. A. , Gross R. W. F. , Spencer D. J.
Published: January 2004

A cw hydrogen fluoride laser has been used successfully to separate deuterium from hydrogen by specific photocatalysis of the reaction of methanol with bromine. The strong absorption of H3COH was demonstrated for the HF laser lines P1(5), P1(6), and P1(7) while no absorption by deutero-methanol of the HF beam was observed. Excitation of H2COH by the absorbed beam increased the rate of H3COH removal by reaction with bromine. Irradiation, at 90 W for 60 sec, with the cw hydrogen fluoride laser of a 1 : 1 H3COH : D3COD gas mixture in the presence of bromine produced isotope enrichment to greater than 95% D3COD.
RESISTIVITY OF POLYCRYSTALLINE ALUMINUM AND COPPER IN HIGH MAGNETIC FIELDS: THE EFFECT OF TEMPERATURE AND PURITY
Authors: Fickett F. R.
Published: January 2004

Data are presented on the resistivity of polycrystalline aluminum and copper at 40 kOe and at temperatures from 4 to 30 K. Specimen purity varies over three decades of residual resistance ratio. For either metal, the actual resistivity measured in the field at a given temperature decreases with increasing specimen purity. This result is important for proposed high magnetic field applications of these metals.
CHEMICAL QUENCHING OF THE TRIPLET STATE IN FLASHLAMP-EXCITED LIQUID ORGANIC LASERS
Authors: Marling J. B. , Gregg D. W. , Wood L.
Published: January 2004

Greatly improved lasing of flashlamp-excited organic dyes has been achieved by collisionally deexciting the triplet state of dye molecules with newly discovered chemical additives. Experimental results show the quantitative improvement of several principal organic lasing compounds when they are placed in solution with chemical additives. An explanation of the deexcitation mechanism is offered; the criteria for selecting proper chemical additives are listed.
DEFORMATION OF CHOLESTERIC LIQUID CRYSTALS WITH LOW THRESHOLD VOLTAGE
Authors: Helfrich W.
Published: January 2004

It is shown theoretically that the orientation pattern of cholesteric liquid crystals can be less stable in electric and magnetic fields than was previously thought. Specifically, the planar texture between two conducting glass plates may become unstable at voltages much below those needed to unwind the cholesteric helix.
CIRCUIT-CONTROLLED CURRENT INSTABILITIES IN n-GaAs
Authors: Shaw M. P. , Solomon P. R. , Grubin H. L.
Published: January 2004

A theoretical analysis of an inhomogeneous n-GaAs element with low cathode boundary fields in a series L-parallel C circuit shows that, for this circuit, the dominant mode of circuit-controlled oscillation is the quenched multiple dipole relaxation mode. LSA relaxation oscillations occur only for a narrow range of circuit parameters and LSA sinusoidal voltage oscillations are excluded, even for elements with small doping fluctuations. This produces an upper frequency limit for circuit control which must be considered in addition to that imposed by finite intervalley relaxation times. We report experimental results that are in qualitative agreement with theory.
SELF-INDUCED THERMAL LENS EFFECT IN CCl4 IN THE PRESENCE OF BEAM MOTION
Authors: Hull R. J. , Kelley P. L. , Carman R. L.
Published: January 2004

The effect of transverse beam motion on the thermal lens effect in a liquid is studied. The beam intensity is found to peak as a function of speed of motion and to fall considerably below the value expected from linear optics for very slow speeds.
GAMMA SPECTROSCOPY WITH SEMIINSULATING CADMIUM TELLURIDE
Authors: Zanio K. , Montano H.
Published: January 2004

Surface barrier detectors were fabricated from vapor-grown semiinsulating CdTe. Photo-peaks were well resolved at room temperature and at 90 % charge collection efficiency for γ emitters ranging from 57Co (122 keV) to 60Co (1.17 and 1.33 MeV). Although a resolution of 16 % (FWHM) could be attained with 137Cs (662 keV), the 1.17- and 1.33-MeV peaks from 60Co could not be separated.
REVERSIBLE ULTRAVIOLET IMAGING WITH LIQUID CRYSTALS
Authors: Margerum J. D. , Nimoy J. , Wong S. -Y.
Published: January 2004

Light-scattering images are recorded in nearly real-time in nematic liquid crystals. The material is activated by ultraviolet exposure of a photoconductive ZnS layer on one of the Nesa electrodes with which an electrical field is applied. In a room-temperature nematic liquid crystal, an incident ultraviolet exposure pulse of 0.1 mJ/cm2 produces an image in a risetime of 0.1 sec, and it decays in 2.5 sec. Long-lived images can be stored in nematic/cholesteric mixtures.
STANDING-WAVE SATURATION RESONANCES IN THE CO2 10.6-μ TRANSITIONS OBSERVED IN A LOW-PRESSURE ROOM-TEMPERATURE ABSORBER GAS
Authors: Freed Charles , Javan Ali
Published: January 2004

The standing-wave saturation resonances are observed by subjecting the CO2 absorber gas to the standing-wave 10.6-μ laser field and detecting the change induced in the entire 4.3-μ (001) → (000) spontaneous emission band as the laser frequency is tuned within the Doppler profile of a specific 10.6-μ transition. Long-term stabilization on any oscillating transition is achieved.
QUANTUM YIELD OF GaAs SEMITRANSPARENT PHOTOCATHODE
Authors: Liu Y. Z. , Moll J. L. , Spicer W. E.
Published: January 2004

The quantum yield of a semiconductor thin-film photocathode, operating in the transmission mode, has been derived from the continuity equation and light multiple reflections within the film and the substrate. The fit between experiment and theory is good for hv<1.7 eV. The differences between experiment and theory are explained in terms of the nonuniform population of defect states within the film. Electron diffusion lengths are found to be 0.3μ for the 1×1019 Zn-doped 2.5-μ -thick film and 0.1μ for the 3×1019 Zn-doped 0.85-μ -thick film, respectively.
DISLOCATION CELL STRUCTURE AND ANOMALOUS CRITICAL FIELDS FOR SUPERCONDUCTIVITY IN SEVERELY DEFORMED NIOBIUM
Authors: Hill D. C. , Rose R. M.
Published: January 2004

The dependence of the anisotropy of the resistive critical field of severely deformed Nb on plastic strain and temperature, the anomalously large stress dependence, and the existence of resistive transitions in fields up to 48 kG all confirm the role of the dislocation cell wall in giving rise to critical-field enhancement in this material.
UNIDIRECTIONAL ULTRASONIC AMPLIFICATION IN A LASER-PUMPED MEDIUM
Authors: Piltch M. , Cassedy E. S.
Published: January 2004

Unidirectional parametric amplification of an ultrasonic wave propagating in a laser-pumped birefringent medium was observed. Using x-cut quartz pumped by a ruby laser, power gains approaching 10 dB were measured at ultrasonic frequencies in the neighborhood of 75 MHz. The effect was identified as a ``coflow''-type parametric interaction.
MINORITY CARRIER LIFETIME IN ION-IMPLANTED AND ANNEALED SILICON
Authors: Davies D. Eirug , Roosild S. A.
Published: January 2004

Results are presented of an investigation to determine whether minority carrier lifetime within ion-implanted layers can be restored to preirradiation levels by annealing. Reverse-recovery measurements were conducted on diffused diodes damaged on the low-doped side by light doses of carbon. The results show that practically complete recovery can be obtained, but annealing beyond the 400°C range associated with light-dose lattice reordering to as high as 600–650°C is required.
JUNCTION LASERS WHICH OPERATE CONTINUOUSLY AT ROOM TEMPERATURE
Authors: Hayashi I. , Panish M. B. , Foy P. W. , Sumski S.
Published: January 2004

Double-heterostructure GaAs–Alx Ga1−x As injection lasers which operate continuously at heat-sink temperatures as high as 311°K have been fabricated by liquid-phase epitaxy. Thresh-olds for square diodes as low as 100 A/cm2 and for Fabry-Perot diodes as low as 1600 A/cm2 have been obtained. Some details of preparation and properties are given.
OBSERVATION OF AN ENHANCED LAMB DIP WITH A PURE Xe GAIN CELL INSIDE A 3.51-μ He–Xe LASER
Authors: Wang S. C. , Byer R. L. , Siegman A. E.
Published: January 2004

The observation of an enhanced Lamb dip is reported for a pure Xe136 gain tube in a He–Xe136 laser cavity. The pure Xe gain cell is operated at a pressure of 5 mTorr so that pressure broadening effects are negligible. The observed enhanced Lamb dip has a 5 MHz width and a depth which is 10% of the peak power. It is estimated that frequency stabilization at 3.51μ to one part in 1011 is possible using the enhanced Lamb dip as a reference.
SILICON (111)−7 STRUCTURE OBTAINED BY CLEAVAGE AT ROOM TEMPERATURE
Authors: Ridgway J. W. T. , Haneman D.
Published: January 2004

It has been found that the Si (111)−7 structure can be observed within a few seconds of cleavage at room temperature. High-temperature heat treatment of the surface, previously thought to be essential to produce the structure, is not required. Auger spectra of both the (7×7) and (2×1) structures obtainable on room-temperature cleavage are identical. To obtain the ``cold'' (7×7) structure, the crystals have been annealed at some period (up to several days) prior to cleavage. The cleavage must be characterized by minimal pressure rise and only minor fracture marks. If impurities are at all involved in the (7×7) structure, these results show that the only ones required are those inherently in the cleavage surface.
UNIAXIAL MAGNETIC GARNETS FOR DOMAIN WALL ``BUBBLE'' DEVICES
Authors: Bobeck A. H. , Spencer E. G. , Van Uitert L. G. , Abrahams S. C. , Barns R. L. , Grodkiewicz W. H. , Sherwood R. C. , Schmidt P. H. , Smith D. H. , Walters E. M.
Published: January 2004

A number of nonmagnetostrictive flux-grown garnets have been developed for use in cylindrical magnetic domain ``bubble'' devices. It has been discovered that the material directly beneath the natural {211} facets is magnetically uniaxial. A model relating the required cutting procedure to composition is presented.