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121.
Space-charge waves in an electron-hole system are studied, which are excited by a moving grating provided by a surface acoustic wave (SAW). The SAW induces a constant current that may change its sign, when a constant electric field is applied opposite to the wave propagation direction. Current resonances are predicted to appear, when the SAW wavelength and frequency match the ones of the space-charge wave. 相似文献
122.
A.A. Morozov 《Applied Surface Science》2006,252(8):2978-2988
The back flux value at polyatomic gas expansion under pulsed laser evaporation is determined on the basis of one-dimensional direct Monte Carlo simulation. Calculations are performed for a wide range of evaporated matter amount. Taking into account rotational and vibrational degrees of freedom substantially increases the back flux. Dependence of the back recondensed fraction on the relaxation collision number is shown. The data are generally in good agreement with available analytical predictions. Importance of consideration of energy transfer from the internal degrees of freedom to the translational ones is illustrated by an example of pulsed laser evaporation of polytetrafluoroethylene (PTFE) and polymethylmethacrylate (PMMA). 相似文献
123.
The lifetime of the surface plasmon in sputtered Ag ultrathin films on Cu(111) was investigated by high‐resolution electron energy loss spectroscopy measurements. The linewidth of the surface plasmon was found to follow a square‐root dependence on the fluence. Such finding allows the tuning of the lifetime of the plasmonic excitation upon sputtering and has general implications in plasmon‐based spectroscopies and in plasmon‐mediated processes across the films and at their surfaces. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
124.
Kazuhiko Nakamura Hiroshi Y. Yoshikawa Yoichiroh Hosokawa Ryota Murai Yusuke Mori Takatomo Sasaki Hiroshi Masuhara 《Applied Surface Science》2007,253(15):6425-6429
We succeeded in generating femtosecond laser-induced crystallization of hen egg-white lysozyme (HEWL) in the irradiated area by suppressing convection of the solution using a highly concentrated gel. When a laser pulse, whose energy was above the threshold energy for bubble formation, was focused along with a linear scanning of the stage, HEWL crystallization was enhanced at the surface of bubbles on the irradiated line. The relation between the bubble formation process and the crystallization is discussed. 相似文献
125.
The polarisability of the system consisting of two parallel thin metallic slabs within the jellium model is obtained within the assumption that the electron densities of the slabs do not overlap. It is then used to calculate, for the first time, the excitation spectra and dispersion relations of the collective surface excitations of that system. The dispersion relations are compared with the classical ones to enable the classification of the excitation modes. 相似文献
126.
M.P. Petrov V.V. Bryksin S. Wevering E. Krätzig 《Applied physics. B, Lasers and optics》2001,73(7):699-703
For the first time the effects of overall doubling, spatial doubling, and overall rectification of space charge waves in a
photorefractive crystal (Bi12GeO20, BGO) have been detected and theoretically studied. The effects of overall doubling and overall rectification resemble second-harmonic
generation and rectification of light in nonlinear optics. A good agreement between theory and experiment is found for the
effect of spatial doubling, while for overall doubling and overall rectification effects only a qualitative agreement between
theory and experiment has been established until now.
Received: 13 July 2001 / Published online: 10 October 2001 相似文献
127.
The dynamics of a laser ablation plume during the first stage of its expansion, just after the termination of the laser pulse is modelled. The one-dimensional expansion of the evaporated material, considered as an ideal fluid, is governed by one-fluid Euler equations. For high energetic ions, the charge separation can be neglected and the hydrodynamics equations solved using self-similar formulation. Numerical solution is obtained, first when the laser fluence range is low enough to deal with a neutral vapor, and in a second stage, when ionization effects on the expansion are taken into account, for different material targets. As a main result, we found that the presence of ions in the evaporated gas enhances the self-similar expansion. 相似文献
128.
Xiaochang Ni Ching-yue Wang Li Yang Jianping Li Lu Chai Wei Jia Ruobing Zhang Zhigang Zhang 《Applied Surface Science》2006,253(3):1616-1619
Ablation process of 1 kHz rate femtosecond lasers (pulse duration 148 fs, wavelength 775 nm) with Au films on silica substrates has been systemically studied. The single-pulse threshold can be obtained directly. For the multiple pulses the ablation threshold varies with the number of pulses applied to the surface due to the incubation effect. From the plot of accumulated laser fluence N × ?th(N) and the number of laser pulses N, incubation coefficient of Au film can be obtained (s = 0.765). As the pulse energy is increased, the single pulse ablation rate is increasing following two ablation logarithmic regimes, which can be explained by previous research. 相似文献
129.
Guo-Ping Guo Xi-Feng Ren Yun-Feng Huang Chuan-Feng Li Zhe-Yu Ou Guang-Can Guo 《Physics letters. A》2007
We experimentally study two-photon coherence in plasmon-assisted transmission with a two-photon Mach–Zehnder (MZ) interferometer. Two collinear photons of identical or orthogonal polarization are simultaneously incident on one optically thick metal film, perforated with a periodic array of subwavelength holes. Interference fringes with two-photon de Broglie wavelength are observed, which indicates that the quantum coherence of biphoton is preserved in surface plasmon assisted transmission. 相似文献
130.
A. Gold 《Zeitschrift für Physik B Condensed Matter》1995,97(1):119-125
We calculate the plasmon dispersion of electron superlattices by taking into account many-body effects via the local-field correction. For small electron density we find a weak roton structure in the dispersion of optical plasmons. Landau damping is strongly enhanced by many-body effects, especially for acoustical plasmons. We compare with experimental results of high-T
c
superconductors. Some experiments are suggested. 相似文献