菲涅耳数

并且由此考察了一般的菲涅耳数计算公式的使用条件。

The application condition of general Fresnel number formula is also studied .

并对菲涅耳数这一物理概念进行了论述。

The concept of Fresnel number is also discussed .

用光线矩阵元表达的菲涅耳数

The Fresnel number in terms of ray matrix elements

正多边形和狭缝的等效菲涅耳数

Equivalent Fresnel Numbers for Regular Polygon Aperture and Slit

有效菲涅耳数与稳定腔的损耗

Effective Fresnel number and diffraction losses of modes in a stable optical resonator

高斯光束的菲涅耳数和聚焦特性

Fresnel Number and Focusing Property of Gaussian Beam

正三边形光阑的等效菲涅耳数

Equivalent Fresnel number for regular triangle aperture

透镜的菲涅耳数越小，焦移越大；

It is shown that the smaller the Fresnel number , the larger the focal shift ;

数值计算结果表明，光谱开关主要与截断参量、光束菲涅耳数以及光谱相干度有关。

The number of spectral switch increases with increasing Fresnel number and truncation parameter , but .

当菲涅耳数一定时，环形透镜的中心拦截比越大，焦移越大；

For a fixed Fresnel number , the larger the central obstruction ratio is , the larger the focal shift is .

光谱开关的个数随着光束菲涅耳数以及截断参量的增大将增多，而随光谱相干度的增大而减少。

The number of spectral switch increases with increasing Fresnel number and truncation parameter , but decreases with increasing spectral degree of coherence .

研究表明，高斯光束通过球差透镜的聚焦特性由球差透镜的类型、球差大小和光束的菲涅耳数共同决定。

It is show that the focusing properties depend on the type of the spherically aberrated lenses , the spherical aberration coefficient and Fresnel number .

结果显示，对于相干度一定的部分相干光束，当菲涅耳数小到一定程度时，部分相干局域空心光束的现象将消失。

We find that , for a certain degree of spatial coherence , the partially coherent bottle beam disappears if the Fresnel number is too small .

运用矩阵本征值方法，对用位相型二元光学元件构成的激光谐振腔进行了数值计算，重点分析了圆形反射镜腔在不同菲涅耳数条件下的模结构参量特性。

The matrix eigenvalues method is used to analyze the laser cavity in which the traditional spherical mirror is replaced by the phase type diffraction optical elements .

为了说明等效菲涅耳数的定义，将由这种简单的新方法得到的结果与基于衍射积分的数值计算得到的结果进行比较，结果显示，两种方法得到的结果吻合的很好。

To evaluate our approach , we make the comparison between the results obtained by this new method and the numerical calculation based on the diffraction integral .

最后，把菲涅耳数推广到复数域，并用于研究截断高斯光束的衍射问题。

Finally we extend the Fresnel number to the region of complex number , and use it to investigate the diffraction problem of a truncated Gaussian beam .

数值计算结果表明，最佳滤波小孔尺寸与系统菲涅耳数、光束截断参数以及光束的位相畸变参数等有关。

Numerical calculations have shown the dependence of the optimum pinhole size on the Fresnel number of the system , the truncation parameter and the phase fluctuation parameter .

数值计算表明，聚焦双曲正弦高斯光束的焦移与偏心参数和菲涅耳数有关，焦移随偏心参数和菲涅耳数的减小而增大。

Numerical calculations are performed and show that the focal shift in focused sinhGaussian beams depends on the Fresnel number and decentered parameter , and increases with decreasing them .

解析公式有利于研究厄米-高斯光束的轴上光强分布与菲涅耳数、截断参数和光束模式等之间的关系。

It is helpful for us to study the relationship between the on-axis intensity distribution and the Fresnel number , truncation parameter and beam order with the analytical expression .

数值结果表明，当透镜的球差系数为负时，在聚焦光场的两个位置，得到了平顶激光光强分布。还讨论了透镜的菲涅耳数对平顶激光光强分布及其出现位置的影响。

The numerical results show that , when the coefficient of the spherical aberration is negative , one can obtain flattened laser intensity profile in two positions along the focused field .

研究表明：受光阑限制离轴高斯光束的光强分布与菲涅耳数、截断参数、相对传输距离、光束的相对偏移和倾角有关。

It is shown that intensity distribution of apertured off-axes Gaussian beam depends on the Fresnel number , truncation parameter , relative propagation distance , relative excursion and obliquity of the beam .

本文分析高斯光束菲涅耳数和聚焦高斯光束各参数之间的关系，给出了一种简便的设计方法。

The relations between the Fresnel number of a Gaussian beam and the parameters of the focusing Gaussian beam are analysed in this paper . And a simple method of design is given .

并且，焦移量不仅依赖于透镜外半径的菲涅耳数，还依赖于部分相干光的空间相干度和中心拦截比。

Moreover , the amount of the focal shifts depends on the Fresnel number of the focusing lens , the spatial coherence of the partially coherent light and the central obstruction ratio of the annular lens etc.

数值计算结果表明近场和远场光强分布与截断参数、系统菲涅耳数、光束的振幅调制和位相畸变参数均有关。

Numerical calculation results have illustrated that the intensity distributions in the near and far fields are dependent on the truncation parameter , Fresnel number of the system , and parameters of amplitude modulations and phase fluctuations .

研究表明，截断平顶高斯光束的焦移不但由光束的阶数N、光束菲涅耳Fw决定，还与孔径菲涅耳数Fa有关。

It is shown that focal shifts of apertured FGBs not only depend on the beam order N , Fresnel number F w associated with the beam , but also depend on the Fresnel number F a associated with the aperture .

从惠更斯-菲涅耳原理出发，推导了部分相干光束通过环形透镜系统的传输公式，分析了空间相干度、菲涅耳数、拦截系数对系统中光束的聚焦光强和焦移的影响。

Based on the Huygens-Fresnel principle , we have derived the propagation expressions of the partially coherent beams passing through an annular lens optical system . The influence of the spectral degree of coherence , Fresnel number and truncated parameter on the focused intensity distribution and focal shift is analyzed .

基于惠更斯-菲涅耳衍射积分公式，研究了宽带光束在菲涅耳衍射区的自由空间传输特性，得到宽带光束传输的调制深度与光束带宽Δλ及菲涅耳数F的变化关系。

The free space propagation property of broadband laser beam in Fresnel diffraction area is studied based on Huygens-Fresnel diffraction integral . The relationship between modulation depth , bandwidth Δλ and Fresnel number is obtained .