共查询到20条相似文献,搜索用时 125 毫秒
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利用掺杂KNSBN晶体,报道了两束异常偏振光所引起的各向异性锥形衍射现象。首次观察到一种由三个衍射光锥所组成的各向异性衍射图样,并且提出了由入射光和满足相位匹配条件的前向散射光所参与的光折变四波混频机制。对双光束对称入射这种特殊实验配置情形,给出了衍射光锥的锥角随入射角的变化关系式,理论分析和实验结果符合得很好。 相似文献
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Ce:KNSBN晶体光扇效应的入射光强度阈值特性研究 总被引:5,自引:0,他引:5
采用非同时读出条件下的两波耦合实验装置,以单束光入射Ce:KNSBN光折变晶体,系统研究了Ce:KNSBN晶体中光扇效应随入射光偏振态、入射光强度、光入射角的变化情况.结果表明异常偏振光入射晶体时光扇效应明显,且存在明显的入射光强度阈值特性,入射光强度阈值为38.2 mW/cm2;相同光入射角下,稳态光扇强度随入射光强度的增强而明显变大;对应相同的入射光强度,稳态光扇强度随光入射角θ的增大而增大,当θ为15°时到达峰值,而后随θ的增大而逐渐减小.同时对光扇效应的入射光强度阈值特性以及稳态光扇强度随入射光偏振态、入射光强度、光入射角的变化作出了相应的物理解释. 相似文献
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采用两波耦合非同时读出实验装置 ,测量了掺铈钾钠铌酸锶钡 (Ce∶KNSBN)晶体两波耦合过程中的信号光和抽运光非同时打开条件下两波耦合增益的时间变化规律 ,讨论了光扇的入射光强阈值及光扇效应对两波耦合动态过程的影响。结果表明 :6 32 .8nmHe Ne激光在Ce∶KNSBN晶体中写入体光栅时 ,光扇效应存在明显的写入光强阈值特性 ,当入射光强大于 30mW /cm2 时 ,才存在强烈的光扇效应。利用修正耦合波方程对Ce∶KNSBN晶体中的两波耦合动态过程、增益随着信号光和抽运光打开时间间隔Δt的变化进行了模拟计算 ,理论模拟结果与实验测量结果基本一致 相似文献
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采用非同时读出条件下的两波耦合实验装置,以单束光入射Ce∶KNSBN光折变晶体,系统研究了Ce∶KNSBN晶体中光扇效应随入射光偏振态、入射光强度、光入射角的变化情况。结果表明异常偏振光入射晶体时光扇效应明显,且存在明显的入射光强度阈值特性,入射光强度阈值为38.2mW/cm2;相同光入射角下,稳态光扇强度随入射光强度的增强而明显变大;对应相同的入射光强度,稳态光扇强度随光入射角θ的增大而增大,当θ为15°时到达峰值,而后随θ的增大而逐渐减小。同时对光扇效应的入射光强度阈值特性以及稳态光扇强度随入射光偏振态、入射光强度、光入射角的变化作出了相应的物理解释。 相似文献
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Ce:KNSBN晶体两波耦合中的光扇效应 总被引:15,自引:2,他引:13
采用两波耦合非同时读出实验装置,测量了掺铈钾钠铌酸锶钡(Ce:KNSBN)晶体两波耦合过程中的信号光和抽运光非同时打开条件下两波耦合增益的时间变化规律,讨论了光扇的入射光强阈值及光扇效应对两波耦合动态过程的影响。结果表明:632.8 nm He-Ne激光在Ce:KNSBN晶体中写入体光栅时,光扇效应存在明显的写入光强阈值特性,当入射光强大于30mW/cm^2时才存在强烈的光扇效应。利用修正耦合波方程对Ce:KNSBN晶体中的两波耦合动态过程、增益随着信号光和抽运光打开时间间隔△t的变化进行了模拟计算,理论模拟结果与实验测量结果基本一致。 相似文献
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N. Domènech‐Amador R. Cuscó R. Calarco T. Yamaguchi Y. Nanishi L. Artús 《固体物理学:研究快报》2012,6(4):160-162
We study the excitation wavelength dependence of the Raman spectra of InN nanowires. The $ E_1 ({\rm LO})$ phonon mode, which is detected in backscattering configuration because of light entering through lateral faces, exhibits an upward fre‐ quency shift that can be explained by Martin's double resonance. The $ E_1 ({\rm LO})$ /$ E_2^h $ intensity ratio increases with the excitation wavelength more rapidly than the $A_1 ({\rm LO})/E_2^h $ ratio measured in InN thin films. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The differential cross sections of elastic and inelastic scattering of ~3He ions on ~(13)C and ~(14)C have been studied at an energy of 37.9 MeV with a double folding model based on M3Y-Reid effective nucleon-nucleon interaction.The resulted parameters have been used for the standard Distorted Wave Born Approximation calculations of angular distributions corresponding to different excitations levels of ~(13)C and ~(14)C and deformation parameters have been deduced. 相似文献
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A. G. Ramm 《Journal of statistical physics》2007,127(5):915-934
If A
q(β, α, k) is the scattering amplitude, corresponding to a potential , where D⊂ℝ3 is a bounded domain, and is the incident plane wave, then we call the radiation pattern the function , where the unit vector α, the incident direction, is fixed, β is the unit vector in the direction of the scattered wave,
and k>0, the wavenumber, is fixed. It is shown that any function , where S
2 is the unit sphere in ℝ3, can be approximated with any desired accuracy by a radiation pattern: , where ∊ >0 is an arbitrary small fixed number. The potential q, corresponding to A(β), depends on f and ∊, and can be calculated analytically. There is a one-to-one correspondence between the above potential and the density
of the number of small acoustically soft particles D
m⊂ D, 1≤ m≤ M, distributed in an a priori given bounded domain D⊂ℝ3. The geometrical shape of a small particle D
m is arbitrary, the boundary S
m of D
m is Lipschitz uniformly with respect to m. The wave number k and the direction α of the incident upon D plane wave are fixed. It is shown that a suitable distribution of the above particles in D can produce the scattering amplitude , at a fixed k>0, arbitrarily close in the norm of L
2(S
2× S
2) to an arbitrary given scattering amplitude f(α ', α), corresponding to a real-valued potential q∊ L
2(D), i.e., corresponding to an arbitrary refraction coefficient in D.
MSC: 35J05, 35J10, 70F10, 74J25, 81U40, 81V05, 35R30.
PACS: 03.04.Kf. 相似文献
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Using fits to the available data on the pion and deuteron electromagnetic form factors and the Chou-Yang model, the computed
values of differential cross-sections for high-energy pion-deuteron elastic scattering agree reasonably well with the available
experimental data. Whereas only a shoulder is expected to appear up to energies of several hundreds of GeV, a dip and a secondary
maximum are predicted to be conspicuous only forP
lab≫400 GeV/C. The position of the dip starts at a much lower value, |t
d| ≅ 0.5–0.6 GeV2, as compared to the corresponding position in thepp scattering. The positions of the first dip are plotted against total cross-section which can be verified by future high-energy
experiments. Limitations of the model predictions for ultrahigh energies are pointed out. 相似文献
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F. Aliotta M. E. Fontanella C. Vasi M. Sacchi G. La Manna V. Turco-Liveri 《Il Nuovo Cimento D》1994,16(7):771-781
Summary The statical and dynamical properties of lecithin/H2O/cyclohexane cylindrical reverse micelles are investigated as a function of lecithin volume fraction, ϕ, and temperature
at fixed water/lecithin ratio,w
0. The viscosity data are well fitted by the Cates model when the breathing mode of micelles is taken into consideration, overlapping
with the breaking and reforming mechanisms. We present some results from Brillouin-scattering experiment, performed across
the sol-gel transition. In order to explain the experimentally observed ϕ-dependence of the hyperacoustic parameters, a mechanical
model was developed from which the ϕ-dependence of the micelle size distribution was obtained. From a comparison with the
viscosity data the entanglement length was estimated. Furthermore some new results from an incoherent quasi-elastic neutron
scattering experiment are presented. The whole body of the experimental results suggests for a sol-gel transition triggered
by topologic phenomena. When the lecithin volume fraction increases, the kinetic equilibrium between the breaking and reforming
mechanisms of the micelles shifts the mean micelle length towards higher values and the entanglement of the micelles becomes
highly favourable. The obtained results are discussed and compared with other findings in literature.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
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We argue that the resonant peak observed in neutron scattering experiments on superconducting cuprates and the peak/dip/hump features observed in ARPES measurements are byproducts of the same physical phenomenon: both are due to feedback effects on the damping of spin fluctuations in a d-wave superconductor. We argue that in the superconducting phase, the dynamical spin susceptibility possesses the resonance peak at Ωres∝ξ−1 where ξ is the magnetic correlation length. The scattering of the resonant magnetic excitations by electrons gives rise to a peak/dip/hump behavior of the electronic spectral function, the peak-dip separation is exactly Ωres. 相似文献