The aperture effect on the propagation of partially polarized Gaussian Schell-model beams

Based on the beam coherence-polarization (BCP) matrix approach and propagation law of partially coherent beams, the propagation of partially polarized Gaussian Schell-model (PGSM) beams through an aperture is studied. Numerical calculation results are given to illustrate the propagation-induced polarization changes and irradiance distribution of PGSM beams for the apertured case.     

Propagation properties of partially polarized Gaussian Schell-model beams through an astigmatic lens

Based on the beam coherent-polarization (BCP) matrix approach and propagation law of partially coherent beams, analytical propagation equations of partially polarized Gaussian Schell-model (PGSM) beams through an astigmatic lens are derived, which enables us to study the propagation-induced polarization changes and irradiance distributions at any propagation distance of PGSM beams through an astigmatic lens within the framework of the paraxial approximation. Detailed numerical results for a PGSM beam passing through an astigmatic lens are presented. A comparison with the aberration-free case is made, and shows that the astigmatism affects the propagation properties of PGSM beams.     

Polarization properties of nonparaxial partially polarized Gaussian Schell-model beams

The polarization properties of nonparaxial partially polarized Gaussian Schell-model (PGSM) beams are studied. Based on the beam coherence-polarization matrix, the propagation formula of the degree of polarization for the nonparaxial PGSM beams is derived. The paraxial approximation is dealt with as special cases of our general results. Some conditions that limit the choice of the parameters are established. The sufficiency condition of polarization invariance in propagation for the nonparaxial PGSM beams is derived. By using the derived formulae, the propagation properties of the degree of polarization for the nonparaxial PGSM beam in free space are illustrated and analyzed with numerical examples. Some detailed comparisons of the obtained results with the paraxial results are made.     

Focal shift of partially polarized Gaussian Schell-model beams

A detailed study of the focal shift of partially polarized Gaussian Schell-model (PGSM) beams is made on the basis of the beam coherence-polarization (BCP) matrix approach. It is shown that, apart from the Fresnel number and truncation parameter, the focal shift of PGSM beams depends on the angle of polarizer and the ratio of degree of spatial coherence.     

Propagation properties of partially polarized Gaussian Schell-model beams through an axis-unsymmetric paraxial ABCD system

By using the beam coherence-polarization (BCP) matrix approach, analytical propagation equations of partially polarized Gaussian Schell-model (PGSM) beams through an axis-unsymmetric paraxial optical ABCD system are derived, which enable us to study the propagation-induced polarization changes and irradiance distributions at any propagation distance of PGSM beams through axis-unsymmetric systems within the framework of the paraxial approximation. Detailed numerical results for a PGSM beam passing through a bifocal lens are presented to illustrate the propagation properties of PGSM beams. A comparison with the previous work is also made.     

部分偏振高斯－谢尔模光束在准直和失调光学系统中的传输

利用张量方法导出了部分偏振高斯－谢尔模光束在准直和失调光学系统中的相干－偏振矩阵的传输公式，并以经过失调薄透镜为例，详细讨论了部分偏振GSM光束的传输特性。导出的公式提供了一个研究部分偏振GSM光束在准直和失调光学系统中传输的简便方法。     

Focal shift and focal switch of partially polarized Gaussian Schell-model beams passing through a system with the aperture and spherically aberrated lens separated

Based on the beam coherent-polarization (BCP) matrix approach and propagation law of partially coherent beams, the focal shift and focal switch of partially polarized Gaussian Schell-model (PGSM) beams passing through a system with the aperture and spherically aberrated lens separated is studied in detail. Our main attention is focused on the effect of spherical aberration and partial coherence on the focal shift and focal switch of PGSM beams. It is shown that for polarizer-free case there is no focal switch of PGSM beams, the focal shift of PGSM beams is closely related with spherical aberration coefficient C₄, auto-coherence length σ_a, truncation parameter δ and relative position s/f between the aperture and lens in general, and is independent of the cross-coherence length σ_c. After inserting a polarizer the focal switch can take place. Numerical calculation results are given to illustrate how the spherical aberration and partial coherence affect the focal shift and focal switch of PGSM beams.     

Changes in the spectrum of Gaussian Schell-model beams propagating through turbulent atmosphere

Based on the extended Huygens-Fresnel principle, the spectrum of Gaussian Schell-model (GSM) beams propagating through turbulent atmosphere is derived analytically. It is shown that, if the scaling law is valid, the normalized spectrum S(ω) of GSM beams propagating through turbulent atmosphere is the same as the normalized source spectrum S⁽⁰⁾(ω), whether GSM source is quasi-homogenous or not. On the other hand, if the scaling law fails, S(ω) of GSM is different from S⁽⁰⁾(ω). The structure constant of the refractive index, transverse coordinate of observation point and spatial correlation length of the source affect the spectrum, which is illustrated numerically.     

Propagation of partially polarized Gaussian Schell-model beams in anomalously dispersive media

By use of a tensor method, analytical transform formulae for isotropic partially polarized GSM beams propagating in anomalously dispersive media are derived. Based on the derived formula, the propagation properties of isotropic partially polarized GSM beams in anomalously dispersive media are studied in detail. The results show that the polarization and the irradiance distribution and the coherence degree properties are influenced by the anomalously dispersive media and beam's initial coherence. In addition, the evolution of the spectrum shows that spectrum splitting and spectral shift occur during propagation in anomalously dispersive media.     

Focusing of stochastic electromagnetic Gaussian Schell-model beams through a high numerical aperture objective

Based on vectorial Debye diffraction theory, the focusing properties of stochastic electromagnetic Gaussian Schell-model beams in the focal region of high numerical aperture objective are investigated. Expressions for the intensity distribution and the degree of polarization are derived near the focus. Numerical calculations are performed to analyze the influences of varying corresponding parameters on the changes in the intensity distribution and in the degree of polarization in the focal region.     

光阑对高斯谢尔模型光束偏振特性的影响

根据光束的相干-偏振矩阵理论,应用柯林公式对部分相干光经光阑衍射后的轴向、横向偏振特性从近场区到远场区的演化规律进行了详细的数值计算。经研究表明,由于光阑的衍射效应,使得高斯谢尔模型光束的偏振出现非均匀分布,光束偏振度沿轴向、横向分布出现多峰振荡现象,并且随着光阑截断参数的减小、光束空间相干长度的增大和传输距离的增大,多峰振荡逐渐增强。光束在自由空间沿轴向传输时,在近场区偏振度分布均匀,与源平面相同,随着传输距离的增大和空间相干长度的减小,偏振度沿轴向分布逐渐增大,无振荡现象。     

线偏振高斯光束通过条形浮雕光栅的传输

使用角谱表示和严格的模式理论研究了线偏振高斯光束通过特征尺寸与波长可比拟的条形浮雕光栅的传输，系统参数误差对浮雕层中光强最大值的影响.研究表明，光束在条形浮雕光栅各层中有不同的光强分布，浮雕层的介质填充部分中的光强明显高于展空部分的光强.光栅周期误差对浮雕层中最大光强的影响起主要作用.并利用模拟退火优化算法优化系统参数以控制出射光束的光强分布.     

Spectral shifts of Gaussian Schell-model beams in passage through an astigmatic lens

Starting from the propagation law of partially coherent light, a closed-form expression for the spectrum of Gaussian Schell-model (GSM) beams propagating through an astigmatic lens is derived, which enables us to study the dependence of spectral shift of GSM beams on the astigmatism of the lens and spatial coherence of GSM beams both analytically and numerically. A comparison with the aberration-free case is made, and shows that the astigmatism affects the spectral behavior of GSM beams. Two special cases of the full coherence and incoherence are discussed and illustrated physically.     

Analytic design of an anamorphic optical system for generating anisotropic partially coherent Gaussian Schell-model beams

The analytic design of anamorphic optical system for transforming the coherent Gaussian beam of a He–Ne laser to a partially coherent Gaussian Schell-model beam with an anisotropic cross-section and an anisotropic degree of coherence is described. Design equations are formulated and some design examples are presented.     

直流固态继电器电磁脉冲失效模式实验研究

采用电流注入法对某型直流固态继电器输入端与输出端的电磁脉冲损伤机制及失效模式进行了实验研究,结果表明:输入端注入电磁脉冲信号时,输出端会产生误动作,并可造成输入电路中三极管BE节产生短路损伤,导致输入端施加控制信号时输出端无法导通;输出端注入电磁脉冲信号时,可造成输出电路中MOSFET管的栅极和漏极产生短路损伤,导致输出端短路。     

Focusing properties of Gaussian Schell-model beams by an astigmatic aperture lens

This paper studies the focusing properties of Gaussian Schell-model (GSM) beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of focused GSM beams by an astigmatic aperture lens depend upon the astigmatism of the lens, the coherence of partially coherent light, the truncation parameter of the aperture and Fresnel number. The numerical calculation results are given to illustrate how these parameters affect the focusing property.     

Effect of polarization on the evolution of electromagnetic hollow Gaussian Schell-model beam

Based on the theory of coherence, an analytical propagation formula for partially polarized and partially coherent hollow Gaussian Schell-model beams (HGSMBs) passing through a paraxial optical system is derived. Furthermore, we show that the degree of polarization of source may affect the evolution of HGSMBs and a tunable dark region may exist. For two special cases of fully coherent and partially coherent δ_xx = δ_yy, normalized intensity distributions are independent of the polarization of source.     

Focusing properties of twisted Gaussian Schell-model beams passing through a system: The aperture lens or the aperture and lens separated

Starting from the propagation law of partially coherent light, the focusing properties of twisted Gaussian Schell-model (TGSM) beams passing through an optical system consisting of an aperture lens or through a system consisting of a separated aperture and lens are studied. The propagation expressions for focused TGSM beams have been derived. Our main attention is focused on the effect of the coherence of partially coherent light, the twist parameter and the distance between the aperture and lens on the focusing properties of TGSM beams. Numerical calculation results are given to illustrate how the coherence of partially coherent light, the twist parameter and the distance between the aperture and lens affect the axial irradiance in the focused field.     

Spectral changes of vector Gaussian Schell-model beams passing through an aperture lens

On the basis of the polarization matrix and propagation equation of the cross-spectral density matrix, the spectral changes in the focal plane of vector Gaussian Schell-model (GSM) beams focused by an aperture lens are studied, where the influence of correlation and polarizer on the behavior of the spectral switch is stressed. It is found that the critical position u_c, spectral minimum S_min, and transition height Δ of the spectral switch depend on the auto-correlation but do not depend on the cross-correlation of GSM beams if there is no polarizer. However, in the presence of the polarizer u_c, S_min and Δ depend on both auto- and cross-correlations. The polarizer affects the spectral switch of vector GSM beams, whereas it does not affect the spectral switch of scalar GSM beams.