World Library  



Journal of Applied Physics Collection (168 Books)


 
  • Cover Image

Journal of Applied Physics : Comparison of resonant-phonon-assiste...

By: H. Li, J. C. Cao, Z. Y. Tan, and S. L. Feng

Description: The authors compare resonant-phonon-assisted terahertz quantum-cascade lasers with different active region designs, i.e., one-well injector and three-well module, using an ensemble Monte Carlo method. Carrier transport under injection anticrossing, parasitic anticrossing, and collection anticrossing couplings are investigated for both structures. The results show that the main parasitic current channel is the resonance of the injector 1′ with the lower lasin...

Read More
  • Cover Image

Journal of Applied Physics : Mechanisms of the ultrasonic modulati...

By: Baohong Yuan, John Gamelin, and Quing Zhu

Description: To understand the modulation mechanisms of fluorescence emission induced by ultrasonic waves in turbid media, a mathematical model is proposed and compared with the recent experimental observations of Kobayashi et al. [Appl. Phys. Lett. 89, 181102 (2006) ]. Modulation of fluorophore concentration is considered as the source of the oscillation of fluorescence signals when fluorophore concentration is low enough so that quenching effects can be ignored. By sol...

Read More
  • Cover Image

Journal of Applied Physics : Laser annealing characteristics of mu...

By: Paul DeMange, Christopher W. Carr, Raluca A. Negres, Harry B. Radousky, and Stavros G. Demos

Description: Laser annealing by pre-exposure to subdamage threshold laser pulses is a well-established method to increase the damage performance of bulk KH2PO4 and KDxH2−xPO4 nonlinear optical materials. The origin of laser-induced damage is believed to be localized absorption by a defect structure, either a light-absorbing foreign nanoparticle or a cluster of stoichiometric defects. It has been recently shown that there are at least three populations of such defect stru...

Read More
  • Cover Image

Journal of Applied Physics : Ferromagnetic Cu doped ZnO as an elec...

By: T. S. Herng, S. P. Lau, S. F. Yu, S. H. Tsang, K. S. Teng et al

Description: Ferromagnetic and highly conductive copper doped ZnO (ZnO:Cu) films were prepared by filtered cathodic vacuum arc technique. By employing a biasing technique during growth, the electron concentration and resistivity of the ZnO:Cu films can be as high as 1020 cm−3 and 5.2×10−3 Ω cm, respectively. The ferromagnetic behavior is observed in all the conductive films, but its magnetization is quenched with an increment in carrier concentration, suggesting that car...

Read More
  • Cover Image

Journal of Applied Physics : Optical emission from a high-refracti...

By: Yuji Kuwamura, Minoru Yamada, Ryuichi Okamoto, Takeshi Kanai, and Hesham Fares

Description: An optical emission scheme was demonstrated, in which a high-refractive-index waveguide is excited by a traveling electron beam in a vacuum environment. The waveguide was made of Si–SiO2 layers. The velocity of light propagating in the waveguide was slowed down to 1/3 of that in free space due to the high refractive index of Si. The light penetrated partly into the vacuum in the form of a surface wave. The electron beam was emitted from an electron gun and p...

Read More
  • Cover Image

Journal of Applied Physics : Alternative to classic annealing trea...

By: O. Van Overschelde, G. Guisbiers, F. Hamadi, A. Hemberg, R. Snyders et al

Description: Titanium dioxide thin films have been deposited by reactive magnetron sputtering on glass and subsequently irradiated by UV radiation using a KrF excimer laser. The influence of the laser fluence (F) on the constitution and microstructure of the deposited films is studied for 0.05

Read More
  • Cover Image

Journal of Applied Physics : Simulation of the bulk and surface mo...

By: M. A. Shapiro, K. R. Samokhvalova, J. R. Sirigiri, R. J. Temkin, and G. Shvets

Description: We present a numerical study of the electromagnetic properties of the three-dimensional metallic wire lattices operating at microwave frequencies with applications to advanced accelerating structures and microwave sources. The metallic lattices can be considered as “artificial plasmas” because they demonstrate the properties of plasmas with a negative dielectric constant. Bulk modes in a diamond lattice of metal wires and surface modes on its interface are c...

Read More
  • Cover Image

Journal of Applied Physics : Spectroscopic characterization of las...

By: Nek M. Shaikh, Sarwat Hafeez, M. A. Kalyar, R. Ali, and M. A. Baig

Description: We present optical emission studies of the laser ablation brass plasma generated by the fundamental, second, and third harmonics of a neodymium doped yttrium aluminum garnet laser. The spectra predominantly reveal the spectral lines of the neutral and singly ionized copper and zinc. The excitation temperatures are determined by the Boltzmann plot method, whereas the electron number densities have been extracted from the Stark broadened line profiles. The spa...

Read More
  • Cover Image

Journal of Applied Physics : Subwavelength imaging based on freque...

By: Stanislav Maslovski, Pekka Alitalo, and Sergei Tretyakov

Description: A new principle of subwavelength imaging based on frequency scanning is considered. It is shown that it is possible to reconstruct the spatial profile of an external field exciting an array (or coupled arrays) of subwavelength-sized resonant particles with a frequency scan over the whole band of resonating array modes. During the scan it is enough to measure and store the values of the near field at one or at most two points. After the scan the distribution ...

Read More
  • Cover Image

Journal of Applied Physics : Observation of coherent acoustic and ...

By: Alexandre A. Kolomenskii, Sergey N. Jerebtsov, Haidong Liu, Hong Zhang, Zuxin Ye et al

Description: Coherent acoustic and optical phonon oscillations in Bi nanowire samples were studied with a femtosecond pump-probe technique. Laser pulses of 50 fs excited simultaneously acoustic oscillations at a frequency of about 9.5 GHz and optical phonons in the terahertz range. The transmission signal of nanowires on a glass substrate and the signal of light scattered from freestanding nanowires were measured. The acoustic velocity in nanowires was found to be close ...

Read More
  • Cover Image

Journal of Applied Physics : Dependence on chirp rate and spectral...

By: H. Murakami, K. Shimizu, M. Katsurada, and S. Nashima

Description: Single-shot measurement of a terahertz field pulse waveform by electro-optic sampling using a chirped optical pulse and a spectrometer was demonstrated by and Jiang and Zhang [Appl. Phys. Lett. 72, 1945 (1998) ]. We have performed an experimental and theoretical investigation into the dependence of the waveform thus measured on the chirp rate and spectral resolution. It was found that the waveform exhibits multicyclic behavior at a chirp rate of −0.24 THz2, ...

Read More
  • Cover Image

Journal of Applied Physics : Optical emission and energy disposal ...

By: M. Villagran-Muñiz, H. Sobral, C. A. Rinaldi, I. Cabanillas-Vidosa, and J. C. Ferrero

Description: A method to simultaneously measure the fraction of incident energy spent as absorbed, scattered, and consumed energy by the plasma generated in the ablation process is presented. The results obtained allowed to make an energy balance in the ablation process of halogenated earth alkaline metal crystals (NaCl, BaF2, and CaF2) and to relate the nature of the crystal structure to the absorbed energy. The latter could be determined by monitoring the magnitude of ...

Read More
  • Cover Image

Journal of Applied Physics : Molecular second harmonic generation ...

By: I. Berline, C. Fiorini-Debuisschert, C. Royal, L. Douillard, and F. Charra

Description: We report the measurement of efficient second harmonic generation at a metallic tip immersed in a molecular solution of highly nonlinear molecules. The dependence of the signal either with the tip-to-substrate applied voltage or with the tip-to-substrate distance is studied. We show that the signal originates from the orientation of a limited number of molecules following local centrosymmetry breaking under the tip. The results are discussed within the conte...

Read More
  • Cover Image

Journal of Applied Physics : Growth and characterization of Er-dop...

By: Andrea Arcangeli, Daniela Parisi, Alessandra Toncelli, Mauro Tonelli, Marco Bazzan et al

Description: Single crystal lithium niobate fibers with diameters ranging from 1 to 3 mm have successfully been grown by the micro-pulling-down technique. The fibers are doped with various Er doping levels from 0 to 0.7 mol % and appear to be transparent and crack-free. The study includes x-ray structural investigation and complete spectroscopic characterization. The analysis shows a good homogeneity of composition, and the comparison with bulk crystals demonstrates the ...

Read More
  • Cover Image

Journal of Applied Physics : Quasi-in-plane leaky modes in lasing ...

By: Lev M. Blinov, Gabriella Cipparrone, Alfredo Mazzulla, Pasquale Pagliusi, Vladimir V. Lazarev et al

Description: Using a planar cell consisting of a prism and a flat glass, we have carried out precise measurements of the angles at which quasi-in-plane leaky (QIPL) laser modes propagate within a thin layer of a cholesteric liquid crystal (CLC) doped with a laser dye. Both the prism and the glass have refraction indices higher than relevant CLC indices, therefore, the waveguide effect in CLC is excluded. For this type of almost thresholdless lasing neither mirrors nor di...

Read More
  • Cover Image

Journal of Applied Physics : Testing the effect of surface coating...

By: S. J. Seltzer, D. M. Rampulla, S. Rivillon-Amy, Y. J. Chabal, S. L. Bernasek et al

Description: The evaluation of different surface coatings used in alkali metal atomic magnetometers is necessary for the improvement of sensitivity of these devices. A method to measure the polarization lifetime of alkali atoms in the region between substrates with different coatings was developed to determine the effectiveness of the coating at preserving alkali spin polarization as well as chemical compatibility and high-temperature stability. Multiple coatings can be ...

Read More
  • Cover Image

Journal of Applied Physics : Efficient formation of surface relief...

By: Sung-Kwan Na, Jung-Sung Kim, Seok-Ho Song, Cha-Hwan Oh, Yang-Kyoo Han et al

Description: This paper reports a method for the efficient formation of surface relief grating (SRG) on azopolymer films in which gold nanoparticles are dispersed. The height and shape of the SRG, which were formed by a two-beam interference technique, were found to be dependent on the content of gold nanoparticles. The optimum concentration of gold nanoparticles for the efficient formation of SRG was confirmed by atomic force microscopy (AFM), and the height of SRG at t...

Read More
  • Cover Image

Journal of Applied Physics : Modification of emission of CdTe nano...

By: Sergei G. Romanov, Maria Bardosova, Ian M. Povey, C. M. Sotomayor Torres, Martyn E. Pemble et al

Description: A light source on the surface of a slab of 2+1-dimensional photonic crystal has been prepared by the Langmuir–Blodgett deposition of a colloidal crystal on top of a thin film containing CdTe nanocrystals. The directional enhancement of the light emission intensity in the spectral range of the photonic bandgap has been revealed through the comparative examination of the angle-resolved transmission, diffraction, and photoluminescence spectra of the prepared st...

Read More
  • Cover Image

Journal of Applied Physics : Three-dimensional modeling of the pla...

By: G. Xu, J. Hu, and H. L. Tsai

Description: Most previous three-dimensional modeling on gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) focuses on the weld pool dynamics and assumes the two-dimensional axisymmetric Gaussian distributions for plasma arc pressure and heat flux. In this article, a three-dimensional plasma arc model is developed, and the distributions of velocity, pressure, temperature, current density, and magnetic field of the plasma arc are calculated by solving the co...

Read More
  • Cover Image

Journal of Applied Physics : Cathode effects in cylindrical Hall t...

By: E. M. Granstedt, Y. Raitses, and N. J. Fisch

Description: Stable operation of a cylindrical Hall thruster has been achieved using a hot wire cathode, which functions as a controllable electron emission source. It is shown that as the electron emission from the cathode increases with wire heating, the discharge current increases, the plasma plume angle reduces, and the ion energy distribution function shifts toward higher energies. The observed effect of cathode electron emission on thruster parameters extends and c...

Read More
 
1
|
2
|
3
|
4
|
5
Records: 1 - 20 of 168 - Pages: 



Copyright © World Public Library. All rights reserved. eBooks from World Public Library are sponsored by the World Public Library Association,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.