jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

15 Jul 2009

Volume 106, Issue 2, Articles (02xxxx)

Page 1 of 7 Pages Next Page | Jump to Page
back to top
RSS Feeds

Photoresistances of semi-insulating GaAs photoconductive switch illuminated by 1.064 μm laser pulse

Minghe Wu, Xiaoming Zheng, Chengli Ruan, Hongchun Yang, Yunqing Sun, Shan Wang, Kedi Zhang, and Hong Liu

J. Appl. Phys. 106, 023101 (2009); http://dx.doi.org/10.1063/1.3172668 (6 pages) | Cited 2 times

Online Publication Date: 17 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Shockley–Read–Hall model (SRHM) and its simplified model (SSRHM) were used to describe the characteristics of a photoconductive semiconductor switch (PCSS) made from a semi-insulating (SI) gallium arsenide (GaAs) chip, biased at low voltage, and illuminated by a 1.064 μm laser pulse. These characteristics include the free carrier densities, dynamic photoresistance, and time evolution of output pulses of the PCSS. The deep donor EL2 centers in SI GaAs play a dominant role in both the SRHM and SSRHM as electrons at EL2 unionized centers are strongly excited by the subband-gap photons at the wavelength of 1.064 μm. Theoretical modeling on the evolution of the experimental measured output pulses led to a two-step micromechanism of electron excitation process within the GaAs chip. The minimum photoresistances predicted by the SSRHM are in good agreement with experimental measurements, which confirms the dominant role of EL2 in the generation of electric pulses from a SI GaAs photoconductivity switch on which the 1064 nm laser pulse is illuminated.
Show PACS
85.60.Bt Optoelectronic device characterization, design, and modeling
71.20.Nr Semiconductor compounds
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
71.55.Eq III-V semiconductors
72.20.-i Conductivity phenomena in semiconductors and insulators
72.40.+w Photoconduction and photovoltaic effects

Electrically controlled reflection bands in a cholesteric liquid crystals slab

A. Castellanos-Moreno, P. Castro-Garay, S. Gutiérrez-López, R. A. Rosas-Burgos, A. Corella-Madueño, and J. Adrian Reyes

J. Appl. Phys. 106, 023102 (2009); http://dx.doi.org/10.1063/1.3153155 (5 pages) | Cited 1 time

Online Publication Date: 20 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We considered a cholesteric slab whose axis is normal to their borders, when a uniform electric field is perpendicularly applied to the helix axis. We found the solution of the boundary value problem for the reflection and transmission of normally incident waves due to the slab. We showed that a left-circularly polarized thin reflection band is immersed in a wider right-circularly polarized band reflection, when the cholesteric is subjected to low amplitude fields. For larger field values, both reflection bands redshift simultaneously as the field increases. A device based on this phenomenon can be used as a electrically tunable universal filter.
Show PACS
61.30.Dk Continuum models and theories of liquid crystal structure
78.20.Jq Electro-optical effects

Pulse shaping and energy storage capabilities of angularly multiplexed KrF laser fusion drivers

R. H. Lehmberg, J. L. Giuliani, and A. J. Schmitt

J. Appl. Phys. 106, 023103 (2009); http://dx.doi.org/10.1063/1.3174444 (10 pages) | Cited 3 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper describes a rep-rated multibeam KrF laser driver design for the 500 kJ Inertial Fusion test Facility (FTF) recently proposed by NRL, then models its optical pulse shaping capabilities using the ORESTES laser kinetics code. It describes a stable and reliable iteration technique for calculating the required precompensated input pulse shape that will achieve the desired output shape, even when the amplifiers are heavily saturated. It also describes how this precompensation technique could be experimentally implemented in real time on a reprated laser system. The simulations show that this multibeam system can achieve a high fidelity pulse shaping capability, even for a high gain shock ignition pulse whose final spike requires output intensities much higher than the ∼ 4 MW/cm2 saturation levels associated with quasi-cw operation; i.e., they show that KrF can act as a storage medium even for pulsewidths of ∼ 1 ns. For the chosen pulse, which gives a predicted fusion energy gain of ∼ 120, the simulations predict the FTF can deliver a total on-target energy of 428 kJ, a peak spike power of 385 TW, and amplified spontaneous emission prepulse contrast ratios IASE/I<3×10−7 in intensity and FASE/F<1.5×10−5 in fluence. Finally, the paper proposes a front-end pulse shaping technique that combines an optical Kerr gate with cw 248 nm light and a 1 μm control beam shaped by advanced fiber optic technology, such as the one used in the National Ignition Facility (NIF) laser.
Show PACS
28.52.Cx Fueling, heating and ignition
28.52.Lf Components and instrumentation
52.57.Kk Fast ignition of compressed fusion fuels
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.55.Lt Gas lasers including excimer and metal-vapor lasers

Application of nanoparticle-containing laser plasmas for optical harmonic generation

R. A. Ganeev, L. B. Elouga Bom, and T. Ozaki

J. Appl. Phys. 106, 023104 (2009); http://dx.doi.org/10.1063/1.3176493 (5 pages) | Cited 4 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanoparticle-containing media can be used for efficient high-order harmonic generation of laser radiation. We present the results of studies of the harmonics generated in the laser-produced plasmas containing Cr2O3, Ag, Cu, and Au nanoparticles. These results are compared with the harmonics generated in the plasma produced on the surface of bulk targets at different delays between the subnanosecond heating prepulse and femtosecond pulse and different intensities of prepulse on the target surface. We discuss the harmonic enhancement, which was observed in the case of nanoparticle-containing plumes with regard to the monoparticle-containing plasmas. Morphological studies of plasma debris confirmed the presence and integrity of nanoparticles in the plumes.
Show PACS
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
52.77.-j Plasma applications
78.47.J- Ultrafast spectroscopy (<1 psec)
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Modeling the temperature characteristics of InAs/GaAs quantum dot lasers

Marco Rossetti, Andrea Fiore, Grzegorz Sęk, Carl Zinoni, and Lianhe Li

J. Appl. Phys. 106, 023105 (2009); http://dx.doi.org/10.1063/1.3176499 (8 pages) | Cited 2 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A systematic investigation of the temperature characteristics of quantum dot lasers emitting at 1.3 μm is reported. The temperature dependence of carrier lifetime, radiative efficiency, threshold current, differential efficiency, and gain is measured, and compared to the theoretical results based on a rate equation model. The model accurately reproduces all experimental laser characteristics above room temperature. The degradation of laser characteristics with increasing temperature is clearly shown to be associated to the thermal escape of holes from the confined energy levels of the dots toward the wetting layer and the nonradiative recombination therein.
Show PACS
42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.63.Kv Quantum dots

Study of polarization properties of light emitted from a-plane InGaN/GaN quantum well-based light emitting diodes

Hung-Hsun Huang and Yuh-Renn Wu

J. Appl. Phys. 106, 023106 (2009); http://dx.doi.org/10.1063/1.3176964 (6 pages) | Cited 16 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper discusses the optical characteristics of a nonpolar a-plane InGaN/GaN quantum well with different indium compositions, quantum well widths, and injection carrier densities. The self-consistent Poisson and 6×6 k⋅p Schrödinger solver has been applied to study the band structures in nonpolar a-plane InGaN-based quantum well light emitting diodes (LEDs). We find that the larger indium composition and smaller well width make the energy separation of |Y〉-like state to |Z〉-like state larger, and as a result enhance the polarization ratio of light. However, the polarization ratio decreases as the carrier injection increases, which might be a drawback for high power applications. We have studied the optimization condition for designing the a-plane InGaN quantum well LED for applications, such as liquid crystal display backlight modules and lasers, which would be useful information for device designs.
Show PACS
85.60.Jb Light-emitting devices
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Birefringence and absorption coefficients of alpha barium borate in terahertz range

Jingle Liu and X. C. Zhang

J. Appl. Phys. 106, 023107 (2009); http://dx.doi.org/10.1063/1.3176965 (5 pages) | Cited 3 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper we experimentally investigated the birefringence and absorption coefficients of alpha barium borate (α-BBO) crystal in the range of 0.3–10 THz by using a broadband air photonic terahertz time-domain spectrometer in both transmission and reflection modes. Several phonon modes were observed for o and e beams. The highest phonon mode at 6.8 THz has absorption coefficient of 1000 cm−1. The comparison between the optical properties of the α-BBO and beta barium borate crystals showed that their phonon frequencies are different and α-BBO crystal has smaller refractive index, birefringence, and absorption coefficients in low frequency region. The blueshift behavior of the lowest phonon of the α-BBO crystal over the temperature range of 10–293 K has also been characterized.
Show PACS
78.20.Fm Birefringence
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.70.-a Optical materials
07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques

Surface plasmon isolator based on nonreciprocal coupling

Juan Montoya, Krishnan Parameswaran, Joel Hensley, Mark Allen, and Rajeev Ram

J. Appl. Phys. 106, 023108 (2009); http://dx.doi.org/10.1063/1.3177341 (6 pages) | Cited 4 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Integrated photonics require optical isolators that achieve low insertion loss and large optical isolation. Here we describe a surface plasmon enhanced optical isolator based on nonreciprocal coupling from a dielectric waveguide coupled to a surface plasmon waveguide. The surface plasmon core consists of a magnetic metal which results in a large nonreciprocity, allowing for device lengths on the order of 50 μm. The analysis and modeling presented here indicate that greater than 30 dB isolation and less than 3 dB insertion loss are possible.
Show PACS
42.79.-e Optical elements, devices, and systems
84.40.Az Waveguides, transmission lines, striplines
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
42.82.-m Integrated optics

Hybrid polymer-porous silicon photonic crystals for optical sensing

L. De Stefano, L. Rotiroti, E. De Tommasi, I. Rea, I. Rendina, M. Canciello, G. Maglio, and R. Palumbo

J. Appl. Phys. 106, 023109 (2009); http://dx.doi.org/10.1063/1.3177344 (5 pages) | Cited 4 times

Online Publication Date: 23 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Porous silicon based one-dimensional photonic crystals, such as Bragg mirror and optical microcavity, has been modified by infiltration of a new biocompatible polymer, an amino functionalized poly(ε-caprolactone) (PCL-NH2), and characterized as optical biochemical sensors. The entrapped polymer adds strong chemical stability to the nanocrystalline matrix on exposure to alkaline solutions preserving the device sensing abilities in monitoring volatile substances and chemical compounds. On the basis of these results, these hybrid structures can be proposed as a high performance platform for biochemical applications.
Show PACS
42.70.Qs Photonic bandgap materials
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
87.15.R- Reactions and kinetics
87.85.J- Biomaterials

Diffractive imaging using a polychromatic high-harmonic generation soft-x-ray source

Ruben A. Dilanian, Bo Chen, Garth J. Williams, Harry M. Quiney, Keith A. Nugent, Sven Teichmann, Peter Hannaford, Lap V. Dao, and Andrew G. Peele

J. Appl. Phys. 106, 023110 (2009); http://dx.doi.org/10.1063/1.3176976 (5 pages) | Cited 6 times

Online Publication Date: 27 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A new approach to diffractive imaging using polychromatic diffraction data is described. The method is tested using simulated and experimental data and is shown to yield high-quality reconstructions. Diffraction data produced using a high-harmonic generation source are considered explicitly here. The formalism can be readily adapted, however, to any short-wavelength source producing a discrete spectrum and possessing sufficient spatial coherence.
Show PACS
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
61.05.cp X-ray diffraction

Spectral properties and luminescence lifetime of blue light of solid state cathodoluminescence based on poly[(2-methoxy-5-(2′-ethyl-hexyloxy)phenylene vinylene]

Chong Qu, Zheng Xu, Xiaoguang Ma, and Xurong Xu

J. Appl. Phys. 106, 023111 (2009); http://dx.doi.org/10.1063/1.3176980 (4 pages) | Cited 1 time

Online Publication Date: 27 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The heterojunction of poly[(2-methoxy-5-(2′-ethyl-hexyloxy)phenylene vinylene] (MEH-PPV)/SiO2 was prepared based on a layered optimization scheme. In three different voltage ranges, the emission spectra of the device changed. The red light was obtained at low applied voltages. With increasing the applied voltages, a blue light was observed. In the medium of the voltage range, one can see both of these two emissions. These two types of the emission resulted from the bombardment of the luminescent material of the MEH-PPV by the hot electron that accelerated in the layer SiO2, which was named solid state cathodoluminescence. In this paper we investigated the spectral properties, frequency response, and luminescence lifetime of blue light in solid state cathodoluminescence.
Show PACS
78.60.Hk Cathodoluminescence, ionoluminescence
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Removing the discontinuous shifts in emission wavelength of a chiral nematic liquid crystal laser

S. M. Morris, A. D. Ford, and H. J. Coles

J. Appl. Phys. 106, 023112 (2009); http://dx.doi.org/10.1063/1.3177251 (4 pages) | Cited 4 times

Online Publication Date: 27 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The laser wavelength of a band-edge liquid crystal laser is known to vary in a stepwise fashion with temperature. This report describes a method for removing the discontinuous shifts in the laser wavelength by doping a nematic sample with two different chiral dopants which exhibit opposing dependences of the natural pitch on temperature. On cooling from the isotropic phase to room temperature the total shift of the laser wavelength is 15 nm with no discontinuities. This is in contrast to that observed for samples consisting of only one chiral dopant whereby the wavelength shift was as large as 75 nm for the same temperature range.
Show PACS
42.55.-f Lasers
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.79.Kr Display devices, liquid-crystal devices

Optical and electro-optic properties of micrometric thick lead zirconate titanate films on (Pb0.86,La0.14)TiO3/glass

M. M. Zhu, Z. H. Du, and J. Ma

J. Appl. Phys. 106, 023113 (2009); http://dx.doi.org/10.1063/1.3176897 (4 pages) | Cited 3 times

Online Publication Date: 28 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly (100)-oriented Pb(Zr0.52,Ti0.48)O3 (PZT) films of up to ∼ 2.4 μm are deposited on the (Pb0.86,La0.14)TiO3 (PLT)-coated amorphous substrate by one cycle of sputtering and annealing. The films possess fibrous columnar nanostructures and vertically grow on the PLT/glass substrate. Microstructure analysis and property characterization indicate that the films possess very promising optical, waveguiding, and electro-optic (EO) properties, as well as low propagation loss. The transparency of >80% in the range of λ = 400–1200 nm and the linear EO coefficient of 341.4 pm/V have been measured in the films. Due to the large EO coefficient and the micrometric thickness, a giant phase retardation of 2.93 rad has been measured under an electric field of 50 kV/mm.
Show PACS
78.66.Nk Insulators
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.20.Jq Electro-optical effects
77.55.-g Dielectric thin films
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
81.15.Cd Deposition by sputtering

Photoelectric effects of ultraviolet fast response and high sensitivity in LiNbO3 single crystal

Er-Jia Guo, Jie Xing, Kui-Juan Jin, Hui-Bin Lu, Juan Wen, and Guo-Zhen Yang

J. Appl. Phys. 106, 023114 (2009); http://dx.doi.org/10.1063/1.3183957 (4 pages) | Cited 5 times

Online Publication Date: 29 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The photoelectric effects in LiNbO3 (LNO) single crystal have been systematically studied with the two kinds of LNO wafers of tilt of 10° and untilted at the ambient temperature. The ultrafast response photoelectric effect of 120 ps rise time was observed in 10° tilted LNO single crystal with a 266 nm laser pulse of 25 ps duration. The photocurrent responsivity of untilted LNO with an interdigitated electrode of 10 μm finger width and 10 μm interspacing is 17.1 mA/W under the irradiation of 300 nm wavelength UV light at 10 V bias. The noise current under sunlight is only 73 pA at 10 V bias. The experimental results suggest that the LNO single crystal is one of the promising materials for photodetectors working in UV region.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Contribution of positive and negative ions to the electrohydrodynamic force in a dielectric barrier discharge plasma actuator operating in air

J. P. Boeuf, Y. Lagmich, and L. C. Pitchford

J. Appl. Phys. 106, 023115 (2009); http://dx.doi.org/10.1063/1.3183960 (9 pages) | Cited 18 times

Online Publication Date: 29 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a parametric study of the electrohydrodynamic force generated by surface dielectric barrier discharge plasma actuators in air for sinusoidal voltage waveforms. The simulation results confirm that momentum is transferred from the charged particles to the neutral species in the same direction during both positive and negative parts of the cycle. The momentum transfer is due to positive ions during the positive part of the cycle (electrode above the dielectric layer is the anode), and to negative ions during the negative part of the cycle. The relative contribution of the positive and negative parts of the cycle depends on the voltage amplitude and frequency. The model predicts that the contribution of negative ions tends to be dominant at low voltage frequencies and high voltage amplitudes.
Show PACS
52.65.-y Plasma simulation
52.80.Tn Other gas discharges
back to top
RSS Feeds

Characterizations of strip-line microwave micro atmospheric plasma and its application to neutralization

Ken Ogata and Kazuo Terashima

J. Appl. Phys. 106, 023301 (2009); http://dx.doi.org/10.1063/1.3153972 (6 pages) | Cited 6 times

Online Publication Date: 16 July 2009

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
In this work, we estimate the plasma parameters of strip-line microwave micro atmospheric plasma (SMMAP) such as rotational temperature (Tr) both from OH and N2 rotational transitions (610–770 and 770–980 K in Ar, respectively), electron density (Ne) from Stark broadening (about 1013/cm3 in mixture of Ar and H2), and the distribution of electric field before ignition of SMMAP (5×104 V/m at maximum, and applied voltage less than 5 V). Since the lower applied voltage of SMMAP might enable us to conduct efficient processing without electrostatic damage (ESD), we applied jet-type SMMAP to neutralization. The result of neutralization showed that it can reduce surface charge from ±1000 to ±100 V for 0.2 s at 10 W with Ar gas flow within 4 V offset voltage, which provides efficient plasma processing without ESD.
Show PACS
52.50.Dg Plasma sources
52.80.Pi High-frequency and RF discharges
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

Influence of sputter rate and crystal orientation on the distribution of carbon in polycrystalline copper surfaces treated by plasma immersion ion implantation

S. Flege, G. Kraft, E. Bruder, K. Baba, R. Hatada, and W. Ensinger

J. Appl. Phys. 106, 023302 (2009); http://dx.doi.org/10.1063/1.3176488 (5 pages) | Cited 1 time

Online Publication Date: 20 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The sputter rate influences the resulting thickness of the carbon containing layer within a surface that was treated by plasma immersion ion implantation. Choosing a polycrystalline substrate with rather large crystals and a material with an inherent high sputter rate, inhomogeneous distributions of carbon over the substrate area due to different thicknesses of the incorporated carbon can be detected. A correlation of three factors namely the carbon x-ray intensity in electron probe microanalysis, the thickness of the carbon layer, and the sputter rate in depth profiling measurements via secondary ion mass spectrometry can be shown. Essential for these factors is the crystal orientation that is visualized by mapping via electron backscatter diffraction. The differences in carbon content due to the orientation are most likely one of the reasons that the adhesion of diamond-like carbon films on copper does not improve with an interlayer of implanted carbon.
Show PACS
61.72.Mm Grain and twin boundaries
52.77.Dq Plasma-based ion implantation and deposition
81.15.Cd Deposition by sputtering
68.55.jd Thickness
81.65.Ps Polishing, grinding, surface finishing
79.20.Kz Other electron-impact emission phenomena
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Plasma uniformity and phase-controlled etching in a very high frequency capacitive discharge

Dougyong Sung, Jehun Woo, Kyungchun Lim, Kyungsun Kim, Vladimir Volynets, and Gon-Ho Kim

J. Appl. Phys. 106, 023303 (2009); http://dx.doi.org/10.1063/1.3176496 (5 pages) | Cited 7 times

Online Publication Date: 20 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of controlled phase shift between very high frequency (100 MHz) voltages applied to the powered electrodes on the plasma uniformity and etch rate was studied in a capacitive triode-type reactor. Radial profiles of plasma optical emission were measured as a function of the phase shift in process (C4F8/O2/Ar) plasma with the low frequency bias power both turned off and on. Radial profiles of KrF photoresist etch rate over a 300 mm wafer were obtained in the same conditions (with the bias power turned on). Besides, plasma density at the wafer center and edge was measured versus the phase shift in pure Ar plasma. It occurred that all measured characteristics strongly depend on the phase shift and correlate with each other. It has been shown that the phase-shift control can considerably improve both the plasma and etch-rate uniformity in very high-frequency capacitive reactors.
Show PACS
52.77.Bn Etching and cleaning
52.80.Pi High-frequency and RF discharges
52.75.-d Plasma devices
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Advanced discharge modes in an ac plasma display with an auxiliary electrode

Sung-Min Lee, Chung Sock Choi, Seung Hun Kim, and Kyung Cheol Choi

J. Appl. Phys. 106, 023304 (2009); http://dx.doi.org/10.1063/1.3176904 (12 pages) | Cited 3 times

Online Publication Date: 22 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The characteristics of advanced discharge modes were investigated through measurements of spatiotemporal infrared emission, discharge current, infrared intensity, and luminous efficacy in an ac plasma display panel with an auxiliary electrode located between scan and common electrodes. Pulse waveforms that included auxiliary pulses applied to the auxiliary electrode after every sustain pulse were used. The proposed advanced discharge modes are as follows: In mode 1, strong discharges are generated by the sustain pulses only, whereas strong discharges are generated by the sustain pulses and a weak discharge is generated by the auxiliary pulse applied after the scan pulse in mode 2. In mode 3-1, strong discharges are generated by the sustain pulses and weak discharges are generated by the auxiliary pulses applied after the scan and common pulses, while all sustain and auxiliary pulses generate discharges having similar intensities in mode 3-2. Mode 1 and mode 2 are efficient modes; the luminous efficacy was improved in mode 1 owing to more homogeneous discharge due to the auxiliary electrode and a priming effect due to the auxiliary pulse. The luminous efficacy was also improved in mode 2, because of decreased power consumption induced by a decrease in wall charges and sustained or increased luminance due to priming particles. Mode 3-1 and mode 3-2 are inefficient modes; the luminous efficacy was reduced in mode 3-1 as a result of a decrease in the luminance due to insufficiently generated priming particles. The luminous efficacy was also reduced in mode 3-2, because of short-coplanar-gap discharges of the sustain pulses. It was found that advanced discharge modes were changed successively from mode 1 to mode 3-2 when sustain or auxiliary pulses of higher voltage were applied. The maximum luminous efficacy can be obtained in mode 1 at a low sustain pulse voltage and in mode 2 at mid and high sustain pulse voltages.
Show PACS
52.75.-d Plasma devices
85.60.Pg Display systems
52.80.-s Electric discharges

Energetic neutrals in the cathode sheath of argon direct-current discharges

Tsuyohito Ito and Mark A. Cappelli

J. Appl. Phys. 106, 023305 (2009); http://dx.doi.org/10.1063/1.3160329 (8 pages)

Online Publication Date: 22 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We recently reported on the direct measurements of the energy distribution of energetic neutrals incident onto the cathode of an argon dc glow discharge [ T. Ito and M. A. Cappelli, Appl. Phys. Lett. 90, 101503 (2007) ]. In this paper, we provide a more extensive report of the experimental data, as well as direct comparisons to Monte Carlo simulations in which neutral-neutral and ion-neutral collision processes are modeled with differential scattering cross sections. The experimental results, which are limited to relatively small forward angle sampling in our present configuration, are found to be in excellent agreement with Monte Carlo simulations. The simulations reveal that high energy neutrals are striking the cathode with a wide range of angles, while ions are more anisotropic. Therefore, it is difficult to predict the neutral energy distribution with commonly used simple analytical models that do not consider scattering of neutrals within the sheath. We propose the use of an extended analytical model in this paper, which seems to provide reasonable energy distributions over the range of discharge voltage studied.
Show PACS
52.40.Kh Plasma sheaths
52.25.Ya Neutrals in plasmas
52.80.Hc Glow; corona
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions
52.65.Pp Monte Carlo methods

Broad, intense, quiescent beam of singly charged metal ions obtained by extraction from self-sputtering plasma far above the runaway threshold

André Anders and Efim Oks

J. Appl. Phys. 106, 023306 (2009); http://dx.doi.org/10.1063/1.3177336 (5 pages) | Cited 4 times

Online Publication Date: 28 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dense metal plasmas obtained by self-sputtering far above the runway threshold are well suited to generate intense quiescent ion beams. The dilemma of high current density and charge state purity can be solved when using target materials of low surface binding energy by utilizing nonresonant exchange reactions before ion extraction. Space-charge-limited quiescent beams of Cu+, Zn+, and Bi+ with ∼ 10 mA/cm2 have been obtained through multiaperture gridded ion extraction up to 45 kV from self-sputtering plasmas.
Show PACS
52.50.Dg Plasma sources
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
52.59.Bi Grid- and ion-diode-accelerated beams
52.25.-b Plasma properties

Dynamics behavior of homogeneous dielectric barrier discharge at atmospheric pressure

Yan Zhang, Biao Gu, Wenchun Wang, Dezhen Wang, and Xuwen Peng

J. Appl. Phys. 106, 023307 (2009); http://dx.doi.org/10.1063/1.3159881 (6 pages) | Cited 2 times

Online Publication Date: 28 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An experimental study on the dynamics behavior of homogeneous dielectric barrier discharge (HDBD) at atmospheric pressure is described in this paper. Two kinds of discharge mode, glow and Townsend discharge modes, can be easily identified according to the differential conductivity of current-voltage relationship in the ascent stage of discharge current for the atmospheric HDBD. A (three-dimensional) 3D phase space made by discharge current, gas gap voltage, and charge density of dielectric-plate surface was utilized in the study. By projecting the discharge evolution trajectory in the 3D space, the 3D trajectory of multiple current peaks discharge in atmospheric helium shows a limited cycle with convolutions and undergoes a series of bifurcation process; however, the 3D trajectory of atmospheric N2 HDBD is a limited cycle without any convolution and bifurcation process. In addition, the first ionization coefficient of working gas plays a key role to determine the discharge mode of atmospheric HDBD, the transition of discharge mode and the dynamics stability of atmospheric HDBD.
Show PACS
52.80.Hc Glow; corona
52.80.Dy Low-field and Townsend discharges
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.25.Fi Transport properties
52.25.Mq Dielectric properties
52.25.Jm Ionization of plasmas

The influence of electrode erosion on the air arc in a low-voltage circuit breaker

Mingzhe Rong, Qiang Ma, Yi Wu, Tiejun Xu, and Anthony B. Murphy

J. Appl. Phys. 106, 023308 (2009); http://dx.doi.org/10.1063/1.3176983 (10 pages) | Cited 3 times

Online Publication Date: 29 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper focuses on the numerical research of the influence of electrode erosion on the arc behavior during opening process of low-voltage circuit breakers. The mathematical model of three-dimensional air arc plasma considering electrode erosion is built based on magnetic hydrodynamics. The mass fraction equation of copper vapor is introduced to the model on the basis of traditional mass, momentum, and energy balance equations. The influence of copper vapor on the thermodynamic and transport properties of the gas mixture is considered in this paper. The distributions of temperature field, gas flow field, and mass fraction of copper vapor in the arc chamber are simulated. The arc root displacements and arc voltage, which takes account of the influence of electrode erosion, are calculated. The simulation results indicate that the immobility time of both moving contact and stationary contact is much longer considering electrodes erosion. The calculated voltage of the arc column during arc motion considering erosion is smaller because of the change in the electrical conductivity of air-copper vapor mixtures. Except for the numerical investigation on the arc motion considering electrode erosion, the experiment work is also carried out to support the simulation work.
Show PACS
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables

Soft x-ray yield from NX2 plasma focus

S. Lee, R. S. Rawat, P. Lee, and S. H. Saw

J. Appl. Phys. 106, 023309 (2009); http://dx.doi.org/10.1063/1.3176489 (6 pages) | Cited 12 times

Online Publication Date: 30 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Lee model code is used to compute neon soft x-ray yield Ysxr for the NX2 plasma focus as a function of pressure. Comparison with measured Ysxr shows reasonable agreement in the Ysxr versus pressure curve, the absolute maximum yield as well as the optimum pressure. This gives confidence that the code gives a good representation of the neon plasma focus in terms of gross properties including speeds and trajectories and soft x-ray yields, despite its lack of modeling localized regions of higher densities and temperatures. Computed current curves versus pressure are presented and discussed particularly in terms of the dynamic resistance of the axial phase. Computed gross properties of the plasma focus including peak discharge current Ipeak, pinch current Ipinch, minimum pinch radius rmin, plasma density at the middle duration of pinch npinch, and plasma temperature at middle duration of pinch Tpinch are presented and the trends in variation of these are discussed to explain the peaking of Ysxr at optimum pressure.
Show PACS
52.58.Lq Z-pinches, plasma focus, and other pinch devices
52.25.-b Plasma properties

Space-charge waves on relativistic elliptic electron beams

Andrew E. Brainerd, Chiping Chen, and Jing Zhou

J. Appl. Phys. 106, 023310 (2009); http://dx.doi.org/10.1063/1.3184424 (4 pages) | Cited 4 times

Online Publication Date: 31 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper reports on results of a small-signal analysis of space-charge waves on a relativistic elliptic electron beam immersed in a strong axial magnet field in a perfectly conducting tunnel with an elliptic cross section. A dispersion relation for the space-charge waves is derived analytically. A computer code, elliptic-beam small signal, is developed and used in studies of the dispersion characteristics of fast- and slow-space-charge waves on relativistic elliptic electron beams. Applications of the theory in elliptic-beam klystrons are discussed.
Show PACS
41.75.Fr Electron and positron beams
84.40.Fe Microwave tubes (e.g., klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.)
Page 1 of 7 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close