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1.
Within the framework of the paraxial approximation, the propagation formula of controllable dark-hollow beams through an annular apertured and misaligned optical system is derived by using the generalized diffraction integral and augmented matrix. Based on the formula, the propagation properties under the very condition are studied in detail. Finally, some numerical examples are given to illustrate the analytical results. It is shown that as controllable dark-hollow beams pass through a circularly apertured misaligned optical system, they become decentered but with the same size of the dark region and the moved central position related to the misaligned parameters εx, εy and ε′x, ε′y. The results can be directly used in the case of other dark-hollow beams, and also can be applied to study other properties. 相似文献
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The approximate analytical expression for the kurtosis parameter of off-axial Hermite-cosine-Gaussian beams (HCosGBs) propagating through apertured and misaligned ABCD optical systems is derived based on the approximate propagation equation of off-axial HCosGBs and an example is given to illustrate for its application. The method used in this paper could be extended to studying the kurtosis parameter of the Hermite-sinusoidal-Gaussian beams passing through apertured and misaligned ABCD optical systems. 相似文献
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Based on the vector angular-spectrum and the complex Gaussian expansion of the aperture function, the structure of an apertured hollow Gaussian beam in the far field is given in a integral form. In virtue of the method of stationary phase approximation, the analytical vectorial structures are derived. Starting from the analytical expressions, the propagation properties of apertured hollow Gaussian beams with different order in the far field are illustrated graphically. In addition, the influence of the truncation parameter on far field distribution is studied detailedly. This research can shed light on the further understanding of the vectorial property of an apertured hollow Gaussian beam. 相似文献
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On the basis of the expansion of the hard aperture function into a finite sum of complex Gaussian functions, the approximate analytical expression of Laguerre-Gaussian beams passing through an annular apertured paraxial ABCD optical system is derived. Meanwhile, the corresponding closed-forms for the unapertured or circular apertured or circular black screen cases have also been given. Numerical examples are given to illustrate the propagation characteristics of Laguerre-Gaussian beams. 相似文献
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A closed-form expression for the one-dimensional off-axial cosine-Gaussian beams passing through an apertured and misaligned paraxially ABCD optical system is derived. As special cases, the corresponding closed-forms for the off-axial or non off-axial cosine-Gaussian beams passing through apertured or unapertured and misaligned or aligned optical systems are also given. The obtained results could be straightforward to the two-dimensional case or sine-Gaussian beams. 相似文献
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厄米-余弦-高斯光束通过具有光阑光学系统时的传输特性 总被引:1,自引:0,他引:1
当厄米_余弦_高斯光束通过带有矩形光阑的一阶ABCD近轴光学系统时,可由Collins公式给出其场分布的积分形式。将其中硬边光阑的窗口函数写成矩形函数,并将矩形函数用高斯函数展开,通过积分可得到由光阑限制的厄米_余弦_高斯光束传输的解析式。分析和讨论了厄米_余弦_高斯光束通过具有圆孔光阑限制的薄透镜系统时的情况,其结果与直接用广义衍射积分公式进行复杂数值计算时的结果完全一致。这样不仅便于进行物理分析,而且也节省了计算机的计算时间。 相似文献
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The closed-form expression for the mean-squared width of apertured partially coherent beams propagating through turbulent media is derived by using the integral transform technique. The influence of turbulence on the spreading of apertured partially coherent beams is studied quantitatively by examining the relative mean-squared width, which is defined as the ratio of the mean-squared width of an apertured partially coherent beam in turbulence to the mean-squared width of the same beam in free space. On the other hand, the range of turbulence-independent propagation, also a reasonable measure of the resistance of a beam to turbulence, is obtained by examining the mean-squared width. It is shown that the spreading of apertured partially coherent beams is less affected by turbulence with smaller truncation parameter δ and coherence parameter α than with larger δ and α. In addition, the influence of turbulence on the spreading of apertured partially coherent beams increases first and then decreases due to increasing waist width w0. The results obtained are explained physically. 相似文献
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实验研究宽频带脉冲光束通过非线性介质时的非线性热像的形成过程,揭示了光束入射功率和脉冲宽度、介质厚度等因素对热像光强和位置的影响. 结果表明,与单纵模激光束一样,在宽频带脉冲光束情形下,非线性介质上游元件的模糊斑调制也可导致在下游共轭位置形成热像. 热像光强随入射光束功率的增加而增加;若脉冲能量一定,则热像光强随脉冲宽度的增加而减弱;若脉冲峰值功率一定,则热像光强随脉冲宽度的增加而增强.
关键词:
高功率激光
热像
宽带光束
小尺度自聚焦 相似文献
14.
Based on the propagation law of cross-spectral density function,
studied in this paper are the coherence vortices of partially
coherent, quasi-monochromatic singular beams with Gaussian
envelope and Schell-model correlator in the far field, where our
main attention is paid to the evolution of far-field coherence
vortices into intensity vortices of fully coherent beams. The
results show that, although there are usually no zeros of
intensity in partially coherent beams with Gaussian envelope and
Schell-model correlator, zeros of spectral degree of coherence
exist. The coherence vortices of spectral degree of coherence
depend on the relative coherence length, mode index and
positions of pairs of points. If a point and mode index are kept
fixed, the position of coherence vortices changes with the
increase of the relative coherence length. For the low coherent
case there is a circular phase dislocation. In the coherent
limit coherence vortices become intensity vortices of fully
coherent Laguerre--Gaussian beams. 相似文献
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The analytical vectorial structure of helical hollow Gaussian beam (HHGB) is investigated in the far field based on the vector plane wave spectrum and the method of stationary phase. The energy flux distributions of HHGB in the far-field, which is composed of TE term with the electric field transverse to the propagation axis, and TM term with the magnetic field transverse to the propagation axis, are demonstrated. The physics pictures of HHGB is illustrated from the vectorial structure, which is important to understand the theoretical aspects of both scalar and vector HHGB propagation. 相似文献
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Beam propagation factor of apertured super-Gaussian beams 总被引:1,自引:0,他引:1
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The spectral behavior of polychromatic spatially fully coherent Gaussian beams diffracted at an aperture in the far field is studied based on the propagation law of the cross-spectral density function. Detailed numerical calculation results are presented, and illustrated. It is shown that the spectral changes take place in the vicinity of zeros of the Airy pattern, and the spectral modifier depends on the truncation parameter δ and diffraction angle α. The critical diffraction angle αc, at which the spectrum is split into two lines with equal height i.e., the spectral switch appears, varies with truncation parameter δ. The spectral switch vanishes if δ becomes large enough. A detailed comparison with the previous publications is given, showing somewhat extension made in our work. 相似文献
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A. Chafiq 《Optics Communications》2006,265(2):594-602
Using Collins formula and the expansion of Mathieu beams in terms of Bessel beams we derive the exact propagation equations of Mathieu-Gauss beams through an apertured paraxial ABCD optical system. A comparison between the exact propagation equations and the approximated ones, which are derived by expanding the circ function into a finite sum of Gaussian functions, is presented. The propagation characteristics of zeroth-order Mathieu-Gauss beams in (y-z) and (x-z) planes are analyzed with detailed numerical calculations. It is found that the profile of the propagated Mathieu-Gauss beam is similar to that of Bessel-Gauss beam. Furthermore, the focalization of the Mathieu-Gauss beams through a thin lens is illustrated and analyzed with numerical results. 相似文献
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Direct acceleration of electrons using two crossed Laguerre--Gaussian laser beams in vacuum 下载免费PDF全文
The basic physical characteristics of electrons accelerated by two linearly
polarized and circularly symmetric crossed Laguerre--Gaussian (LG) laser
beams with equal frequency and amplitude in vacuum are studied in detail.
The condition, under which electrons can be accelerated effectively, and the
energy gain are discussed. 相似文献