多色高斯光束的奇点分布和光谱奇异现象

讨论多色高斯光束经过球差透镜后的奇点和光谱变化.基于光传输变换理论,推导出多色高斯光束经过球差透镜后,焦点附近的强度和光谱分布公式,并进行数值模拟.结果发现,在焦平面附近,轴上奇点分布和光谱变化随着拦截比的改变而改变,当拦截比值小于某一特定值的时候,轴上奇点和光谱奇异现象都会消失.另外,当相位奇点消失时,光谱奇异现象并没有立即消失.当球差系数变大的时候,轴上有些奇点将分裂成两个新奇点,此时通过改变拦截比值的大小,可以看到这些新分裂出的奇点将逐渐汇合,并且慢慢消失.

Distribution of Singularities and Phenomenon of Spectral Changes of Gaussian Beam Focused by Lens with Spherical Aberration

We address the singularities and spectral changes of Gaussian beam focused by lens with spherical aberration(SA).Based on the theory of the optical propagation,the equations of the intensity and the spectral density around the focal plane are derived,according to which we do numerical simulation.The results show that the singularities and spectrum around the focal plane vary with the change of the truncated parameter.The singularities and drastic spectral change vanish when the value of truncated parameter is smaller than some specific value.In addition,the drastic spectral change doesn't disappear immediately at the time of the phase singularity annihilated.Some axial singularities split into two new singularities on account of the increasing value of SA coefficient.These new splitted singularities converge into one singularity again and disappear gradually when the value of truncated parameter is changed.