正交偏振干涉的矢量光场分析和检测

在大学物理中,光的干涉和衍射现象是描述光的粒子性和波动性非常常见的内容。那么光的干涉需满足相干条件,即两束光具有相同的偏振态、相同的频率和固定的相位差。因此,在标量衍射理论中,完全正交偏振的光不能够发生干涉现象。为拓展和探究正交偏振态下两束光相遇时光场的矢量变化,本文构建了基于马赫-曾德尔配置的正交偏振光(即正交线偏振和正交圆偏振)相干涉而产生的光场,利用检偏器检测光场的矢量特征及条纹分布情况。结果表明正交偏振光相干涉产生了周期性的矢量光场。该研究能够帮助学生更加直观的掌握波片及偏振片调制不同偏振态的光束并实现矢量光场的检测和分析。     

偏振光干涉的琼斯矩阵分析

根据琼斯矢量对偏振光的适用性,应用琼斯矩阵推导出了偏振光干涉的表达式,讨论了几例常见的偏振光干涉现象.     

双强度调制偏振光谱测量原理及仿真

针对单强度调制偏振光谱测量技术存在混叠且有效光程差有限的缺点,提出双强度调制偏振光谱测量新方法,该方法通过双强度调制干涉信号的和差处理,即保证单强度调制偏振光谱测量的优点,又能有效消除混叠现象,提高有效光程差和光谱分辨率,再对和差处理后的干涉信号进行傅里叶变换即可得到被测偏振光谱。文章对双强度调制偏振光谱测量方法进行了理论推导,并通过MATLAB对模拟入射光偏振光谱的干涉信号和傅里叶反演光谱进行仿真;仿真结果显示,该方法和差处理后可有效消除混叠且有效光程差提高一倍。通过理论分析和仿真验证了该方法的可行性,为进一步的工程实现提供理论支撑。     

单弹光调制傅里叶偏振光谱测量研究

提出一种基于弹光调制器（photoelastic-modulator, PEM)的复色光偏振光谱的傅里叶测量方法,被测光经过0(-45)弹光调制器调制,通过45(0)检偏器并由探测器探测调制后形成干涉信号,对干涉信号进行傅里叶变换,由所得结果实部和虚部得到被测光Stokes矢量中的S1、S2和S3的光谱。该方法降低了偏振光光程测量的复杂度,给出理论推导过程,并结合仿真结果与理论结果对比,证实了该方法复原后的偏振光谱与原始光谱可很好地吻合。     

单弹光调制傅里叶偏振光谱测量研究

提出一种基于弹光调制器(photoelastic-modulator, PEM)的复色光偏振光谱的傅里叶测量方法,被测光经过0°(-45°)弹光调制器调制,通过45°(0°)检偏器并由探测器探测调制后形成干涉信号,对干涉信号进行傅里叶变换,由所得结果实部和虚部得到被测光Stokes矢量中的S1、S2和S3的光谱。该方法降低了偏振光光程测量的复杂度,给出理论推导过程,并结合仿真结果与理论结果对比,证实了该方法复原后的偏振光谱与原始光谱可很好地吻合。     

两束部分偏振光的干涉场分析

从波的叠加与干涉的基础理论出发,给出了当两束部分偏振光的一个光强极值方向平行时,其干涉场的光强分布和干涉条纹衬比度表达式.该表达式可应用于自然光、线偏振光和由二者组成的部分偏振光参与的干涉过程.在此基础上,对线偏振光与线偏振光、自然光与自然光、线偏振光与自然光等不同偏振态光叠加时的干涉场进行了具体分析,给出了其相应干涉场的光强分布及其干涉条纹衬比度的具体表达式,得到的结果对识别前述各种偏振态光形成的干涉场以及提高干涉仪中相应干涉场的干涉条纹衬比度具有重要意义.     

基于Matlab的单轴晶体锥光干涉图样模拟

根据偏振光干涉原理,在Matlab环境中完成晶体电光调制实验中锥光干涉图样的计算模型建构和仿真模拟,其结果图样细致逼真. 在此基础上,模拟出其他情况下单轴晶体锥光干涉图样,从而使复杂的干涉现象变得直观形象,为光学实验教学提供了有效的辅助手段.     

线偏振光电位移矢量振动方向对InGaP/InGaAs/Ge三结太阳电池开路电压的影响

研究了线偏振光振动方向对InGaP/InGaAs/Ge三结太阳电池开路电压的影响, 结果表明开路电压随线偏振光电位移矢量振动方向按周期性变化,变化的幅度在 1%-4%左右.理论分析证实了线偏振光电位移矢量的调制可以改变太阳电池的输出开路电压,是由于三结太阳电池晶体结构以及应力影响导致能带结构出现各向异性产生的. 此外,实验结合理论分析,研究了三结太阳电池开路电压随光照度的变化关系, 得出开路电压随光强变化成对数关系.拟合结果说明三结级联太阳电池可以简单看成三个单结太阳电池串联,其理想因子接近6,是由于三结太阳电池中缺陷影响的结果.     

三环位相型光瞳滤波器的横向超分辨与轴向焦深扩展

用矢量衍射方法分析了线偏振光入射到带有三环位相型光瞳滤波器的高数值孔径物镜时,焦点的轴向和横向光强分布.数值模拟结果表明,高数值孔径物镜聚焦时需同时考虑光强的轴向和横向分布.通过加入三环位相光瞳滤波器,在实现横向超分辨的同时实现了光学系统轴向焦深扩展和轴向光强分布平坦化,并且位相调制深度变化时,会出现轴向焦移现象.对三环位相光瞳滤波器结构进行了优化,得出了优化结果. 关键词： 光学超分辨 扩展焦深 位相型光瞳滤波器 矢量衍射方法     

基于偏振光相位调制的超衍射极限空间结构光研究

具有超衍射极限尺寸的空间结构光在远场超分辨成像、光镊、微纳米加工等领域都有着重要的应用.本文基于偏振光的相位调制原理,结合光学实验与光场数值模拟开展了在空间生成具有超衍射极限尺寸的空间结构光的研究.首先设计了一种兼备圆形π与涡旋形2π相位板特点的新型相位板,并且实验观察到了高数值孔径系统中新型相位板调制圆偏振高斯光的焦点处的空间结构光形貌.随后通过结合矢量衍射积分理论的数值模拟,得出了一种具有超衍射极限尺寸、且同时呈现中心对称与轴对称的空间结构光.最后,本文详细讨论分析了新型相位板调制圆偏振光、线偏振光、径向偏振光以及角向偏振光所获得的空间结构光分布特点.结果显示,圆、线、径向与角向偏振条件下得到的空间结构光横向最小暗斑的半高全宽分别为0.31λ,0.32λ,0.24λ和0.36λ;在光轴上,线、径向与角向偏振光情况下的中心暗斑的半高全宽分别为0.8λ,0.78λ,0.76λ,而圆偏振光在轴向方向没有电矢量分布.     

Modulation of coherence of vectorial electromagnetic waves in the Young interferometer

We show the modulation of coherence for vectorial electromagnetic waves taking place in the interference plane of a Young interferometer. The amplitude of modulation is determined by the polarization properties at the slits.     

Self-modulation of light in piezoelectric crystals

Spectroscopic measurements were used to monitor the optical interference of ordinary (o-ray) waves with extraordinary (e-ray) waves by incidence of plane-polarized light and transmission through piezoelectriccrystals (alpha-quartz, LiNbO3, and LiTaO3). This observation confirms that the rotations of the vibration planes of the o- and e-ray waves originate from the dynamic gratings induced by the electric field of the incident light. This is a self-modulation process of the polarized incident light in piezoelectric crystals.     

Dynamics of localized structures in vectorial waves

Dynamical properties of topological defects in a two dimensional complex vector field are considered. These objects naturally arise in the study of polarized transverse light waves. Dynamics is modeled by a vector complex Ginzburg-Landau equation with parameter values appropriate for linearly polarized laser emission. Creation and annihilation processes, and self-organization of defects in lattice structures, are described. We find "glassy" configurations dominated by vectorial defects and a melting process associated with topological-charge unbinding.     

Generation and Manipulation of Spin-Orbit Coupling mode via Four-Wave Mixing with Quantum Interference

Recently, the vectorial nonlinear optical processes driven by spin-orbit coupling (SOC) light have come to the fore, leading to striking optical phenomena and important applications both in classical and quantum optics. However, research on the SOC-mediated light-atom interactions is still in its infancy. Here, the generation and manipulation of SOC mode through a vectorial four-wave mixing (FWM) process in ⁸⁵Rb vapor is demonstrated. Under the excitation of two SOC pump beams, multiple FWM paths can be simultaneously established due to the rich atomic Zeeman sublevels coupling with different circularly polarized components of SOC fields. A higher-order cylindrical or more general SOC FWM signal is observed in the vectorial FWM process, which obeys angular momentum conservation and Gouy phase matching. In particular, quantum interference between different FWM paths plays a crucial role in manipulating the SOC mode of the generated FWM signal, revealing that the conversion of SOC mode is intrinsically quantum. This work provides a pathway toward deeper insight into the vectorial nonlinear optical processes and may advance technology for shaping spatially structured light, which is essential in applications such as nonlinear polarization imaging and the optical communication realm.     

Steady-state vectorial self-diffraction on a non-local photorefractive grating in a crystal of symmetry \overline{4}3m at symmetrical transmitting geometry

The steady-state two-wave interaction in a cubic crystal of the symmetry group 3m with the non-local photorefractive response in the absence of an external electric field is considered for the case of arbitrary interaction orientation with respect to the crystallographic coordinate system and for arbitrary intensities and polarization states of incident light waves. The self-diffraction problem is described on the basis of four coupled-wave equations in terms of the complex scalar amplitudes of components of the light waves with orthogonal linear polarization. The derived conservation laws are valid for the non-linear dependency of the photorefractive-grating amplitude on the modulation coefficient of the interference light pattern. It follows from these laws that the two non-unidirectional energy fluxes can form the total energy exchange between the two interacting light waves. A set of independent conservation laws allows us to decouple the coupled-wave equations and to obtain their analytical solution, at least, in the form of quadrature formulae. For example, such a solution is derived for the case of linearly polarized incident light waves and for the linearized dependency of the photorefractive-grating amplitude on the modulation coefficient. The explicit analytical expressions for the scalar amplitudes are obtained for the transversal electro-optic configuration of interaction. The possibility of polarization-state transformation of light waves without energy exchange between them is shown. Received: 30 July 2002 / Published online: 11 December 2002 RID="*" ID="*"Corresponding author. Fax: +7-3822/414321, E-mail: litvinov@ed.rk.tusur.ru     

General representation of interference contrast formed by arbitrarily polarized waves and its application in wave design for holographic fabrication of photonic crystals

A general formula of interference contrast formed by two arbitrarily polarized elliptical waves propagating along arbitrary directions in three-dimensional (3-D) space is derived. From it a series of inferences for the interference of linear and circular waves including their different combinations are obtained. These formulae are used for polarization optimization in three and four noncoplanar beam interference for the fabrication of 3-D periodic microstructures. The numerical calculations show that the use of circular light can improve the uniform contrast considerably compared with the use of only linear light, and the use of elliptical light may make the contrast even higher.     

Interference of circularly polarized light: contrast and application in fabrication of three-dimensional periodic microstructures

The contrast of interference pattern formed by two circularly polarized waves and by a linearly polarized wave and a circularly polarized one is discussed. The results are compared with that by two linear beams. It shows that the use of circular light in holographic fabrication of three-dimensional periodic microstructures may remove the necessity of beam ratio and polarization optimization needed in the interference of three linear noncoplanar beams and improve the uniform contrast of resultant pattern simultaneously.     

两圆偏振光以及线偏振光和圆偏振光干涉图样的衬比度

考察了两束圆偏振光之间以及线偏振光与圆偏振光之间干涉所形成图样的衬比度,并与两束线偏振光之间干涉图样的衬比度进行了比较．指出在非共面多光束干涉中有可能利用圆偏振光以改善干涉图样的整体衬比度,并简要介绍了它在光子晶体制备中的应用．     

The spatial polarization distribution over the dome of the sky for abnormal irradiance of the atmosphere

The paper deals with the polarized radiative transfer within a slab irradiated by a collimated infinitely wide beam of arbitrary polarized light. The efficiency of the proposed analytical solution lies in the assumption that the complete vectorial radiative transfer solution is the superposition of the most anisotropic and smooth parts, computed separately. The vectorial small-angle modification of the spherical harmonics method is used to evaluate the anisotropic part, and the vectorial discrete ordinates method is used to obtain the smooth one. The azimuthal expansion is used in order to describe the light field spatial distribution for the case of abnormal irradiance and to obtain some known neutral points in the sky especially useful for polarized remote sensing of the atmosphere.     

The Imbert-Fedorov shift of paraxial light beams

We present a solution to the problem of reflection and transmission of a polarized paraxial light beam at an interface between two homogeneous media by using a two-form amplitude and an extension matrix to represent the vectorial angular spectrum of a three-dimensional (3D) light beam. We derive general formulas for the Imbert-Fedorov (IF) shift of the reflected and transmitted beams of a polarized paraxial light beam. The IF shift of two different types of polarized beams is calculated, and the influence of the polarization state and the polarization feature of the vectorial angular spectrum on the IF shift is discussed.