共查询到20条相似文献,搜索用时 93 毫秒
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强双折射光纤中单一频率传输区域的调制不稳定性 总被引:5,自引:1,他引:4
利用光脉冲在光纤中传播时所遵守的相干非线性薛定谔耦合方程,研究了单一频率的线偏振光,且偏振方向沿两个双折射轴的分量强度相等时,在反常色散区和正常色散区所产生的调制不稳定性.结果表明在反常色散区和正常色散区,对应不同的功率区域输入脉冲有不同的增益谱,并且当输入脉冲功率一定时,双折射性质变化导致增益谱表现出明显的不同. 相似文献
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含具有双增益线原子的光子晶体中的光传播 总被引:1,自引:1,他引:0
讨论了缺陷层包含具有双增益线的原子的一维光子晶体中的色散效应及透射谱,双增益线间出现了反常色散区,由于入射光与双增益线的相互作用使得光子带隙中出现了两个透射率远大于1的透射峰;透射峰随着缺陷位置和体系结构参数的变化而产生变化;左透射峰和右透射峰很窄的频率范围内分别出现了斜率极大的反常色散和正常色散,产生了负的群速度和极慢光速的光传播行为。 相似文献
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对工作在铷5P1/2→10S1/2(532 nm)跃迁的法拉第反常色散滤光器的传输特性,并对中间场下激发态法拉第反常色散滤光器的理论模型进行了分析与讨论.依据量子力学微扰理论和量子跃迁理论,给予了完整地描述.理论分析结果表明,在气室温度434 K,磁场强度0.067 T,抽运光强度20 W/m2,气室长度0.1 m条件下,法拉第反常色散滤光器处于一个最佳工作状态;期望的线芯工作方式得以实现.中心透射峰适宜作滤光器的信号光通道.理论模型预测滤光器的峰值透过率接近50%,等效带宽仅为2.6 GHz.铷532 nm激发态法拉第反常色散滤光器的光谱特性可用于检测具有重要应用价值的二倍频Nd:YAG激光信号. 相似文献
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The structures of suspensions comprised of magnetic and nonmagnetic particles in magnetic fields are studied using two-dimensional Monte Carlo simulations. The magnetic interaction among magnetic particles, magnetic field strength, and concentrations of both magnetic and nonmagnetic particles are considered as key influencing factors in the present work. The results show that chain-like clusters of magnetic particles are formed along the field direction. The size of the clusters increases with increasing magnetic interaction between magnetic particles, while it keeps nearly unchanged as the field strength increases. As the concentration of magnetic particles increases, both the number and size of the clusters increase. Moreover, nonmagnetic particles are found to hinder the migration of magnetic ones. As the concentration of nonmagnetic particles increases, the hindrance on migration of magnetic particles is enhanced. 相似文献
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Hiroshi Yamaguchi Xiao-Dong Niu Xiao-Jiang Ye Mingjun Li Yuhiro Iwamoto 《Journal of magnetism and magnetic materials》2012
The dynamic rheological properties of viscoelastic magnetic fluids in externally applied uniform magnetic fields are investigated by a laboratory-made cone-plate rheometer in this study. In particular, the effects of the magnetic field on the viscoelastic properties (the complex dynamic modulus) of the viscoelastic magnetic fluids are studied. In the investigation, three viscoelastic magnetic fluids are made by mixing a magnetic fluid and a viscoelastic fluid with different mass ratios. As a supplementation to the experimental investigation, a theoretical analysis is also presented. The present study shows that the viscosity and elasticity of the viscoelastic magnetic fluids are significantly influenced by the magnetic field and the concentrations of the magnetic particles in the test fluids. Theoretical analysis qualitatively explains the present findings. 相似文献
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In situ magnetic hysteresis measurements of magnetic tips in a magnetic force microscope (MFM) are demonstrated using alternating gradient force magnetometry. The measured magnetic moments of MFM tips are estimated in the range from 10−6 to 10−5 emu by this technique and the whole MFM tips in cantilevers are considered to be measured from the value of measured magnetic moments. The relationship between the magnetic hysteresis loops of MFM tips and those of coated magnetic films is discussed. 相似文献
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Flexible magnetic devices, i.e., magnetic devices fabricated on flexible substrates, are very attractive in applications such as detection of magnetic field in an arbitrary surface, non-contact actuators, and microwave devices, due to their stretchable, biocompatible, light-weight, portable, and low cost properties. Flexible magnetic films are essential for the realization of various functionalities of flexible magnetic devices. To give a comprehensive understanding for flexible magnetic films and related devices, recent advances in the study of flexible magnetic films are reviewed, including fabrication methods, magnetic and transport properties of flexible magnetic films, and their applications in magnetic sensors, actuators, and microwave devices. Our aim is to foster a comprehensive understanding of these films and devices. Three typical methods have been introduced to prepare the flexible magnetic films, by deposition of magnetic films on flexible substrates, by a transfer and bonding approach or by including and then removing sacrificial layers. Stretching or bending the magnetic films is a good way to apply mechanical strain to them, so that magnetic anisotropy, exchange bias, coercivity, and magnetoresistance can be effectively manipulated. Finally, a series of examples is shown to demonstrate the great potential of flexible magnetic films for future applications. 相似文献
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Polarization and transmission of microwaves in the magnetic suspension in the applied magnetic field
Stanis?aw Bednarek 《Journal of magnetism and magnetic materials》2011,323(7):957-964
The production method of magnetic suspension consisting of ferromagnetic particles dispersed in cedarwood oil is presented at the beginning of this article. Next, the set-up for microwaves generation using a klystron is described. The main part of this paper concerning microwave transmission and polarization during its passage in samples of the produced magnetic suspension placed in a magnetic field is based on the following parameters: induction of this field, filling factor of magnetic suspension by ferromagnetic particles, dimensions of particles, viscosity of liquid carrier, and ratio of the magnetic field changes. Conducted investigations show that microwaves are damped and polarized in these magnetic suspensions. Obtained results are discussed and observed effects are explained by ordering of ferromagnetic particles in magnetic suspension by applied magnetic field. 相似文献
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提出在典型一阶磁脉冲压缩电路的基础上,测取磁芯在实际工作条件下的动态磁滞回线和饱和磁导率等磁参数,再根据所获得的动态参数指导磁开关设计,进行一阶磁压缩实验。实验选取国内外被广泛应用的非晶磁芯和纳米晶磁芯进行测试,根据实测动态磁参数设计磁开关。实测结果表明:用国产非晶磁芯做磁开关可得到上升沿73 ns、电压幅值28.3 kV、半高宽为503 ns的脉冲,用日本产的纳米晶磁芯做磁开关可得到上升沿30 ns、电压幅值28.4 kV、半高宽为193 ns的脉冲。 相似文献
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F. C. Hoh 《International Journal of Theoretical Physics》1994,33(12):2351-2363
Hadron magnetic moments are considered in the framework of the spinor strong interaction theory for hadron spectra proposed by the author. Expressions of magnetic moments of ground-state hadrons are derived. These differ from the conventional ones in that they are no longer phenomenological and are basically relativistic. Pseudoscalar mesons have no magnetic moment. Charged vector meson magnetic moment values are given. The magnetic moment operators operate in the internal space, so that the ground-state octet baryons have the same spin-space symmetry, including the A. A formula for the ground-state octet baryon magnetic moment is derived from the basic spinor strong interaction baryon equations previously given, essentially without approximation and in a way analogous to the way in which the electron magnetic moment is derived. 相似文献
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The general effective-medium dispersion relations are derived for surface-localized magnetic polaritons which propagate parallel to the surface between a superlattice and semi-infinite bulk material, as applied to ferromagnetic and antiferromagnetic superlattices, in the situation when a static magnetic field is applied in the plane of the layers and parallel to the magnetization. The dependence of the energy of the surface waves on the volume fraction of the ferromagnetic superlattice component and the influence of the external magnetic field on the spectrum of the surface magnetic polaritons for the antiferromagnetic superlattice are investigated. The spectrum of the surface-localized magnetic polaritons which appear at the junction of the magnetic (ferromagnetic and antiferromagnetic) superlattice with the magnetic material are more complex, in contrast to the cases of semi-infinite magnetic material or semi-infinite magnetic SL. It is essential that in all cases in the presence of the external magnetic field the spectrum of the magnetic polaritons are non-reciprocal. The properties of surface polaritons are discussed in detail for the system ferromagnetic superlattice (YIG/non magnet)/YAG and the antiferromagnetic superlattice (MnF2/ZnF2)/FeF2. 相似文献
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《中国物理 B》2015,(12)
Recent discoveries in the synthesis and applications of magnetic vortex nanorings/nanodiscs in theranostic applications are reviewed. First, the principles of nanomagnetism and magnetic vortex are introduced. Second, methods for producing magnetic vortex nanorings/nanodiscs are presented. Finally, theranostic applications of magnetic vortex nanorings/nanodiscs are addressed. 相似文献