高斯光束经局域相位调制后的光强分布和角谱特性

Properties of the Intensity Distribution and the Angular Spectrum of a Gaussian Beam with Local Phase Modulation

光学元件上不可避免地存在的"缺陷"会对传输光束产生局域振幅和相位调制。基于菲涅耳衍射积分,建立了高斯光束经局域相位调制后的传输模型,得到了高斯光束经有限多个小尺寸局域相位调制后的光强分布和角谱解析式,详细研究了相位调制尺寸与调制深度对光束光强分布和角谱的影响。结果表明,不同调制尺寸、调制深度对高斯光束在传输过程中的影响相似。且调制深度越大,产生的最大光强越大。相位"缺陷"尺寸越大产生的最大光强的位置离"缺陷"越远,随着调制深度、尺寸的增大和调制位置距光轴距离越近,低频区的角谱越小,中高频区的角谱越大。

The unavoidable defects exists in the optical component will modulate the phase and the amplitude of the beam propagate in the system.Based on the Fresnel diffraction integral,the propagation mode of the Gaussian beam modulated by the local phase is built and the analytical expressions for the intensity distribution and angular spectrum of a Gaussian beam modulated by finite phase modulated defects has been derived.The impact of the modulation depth and the size of the defects on the intensity distribution and angular spectrum of the beam modulated by phase modulated defects is studied.It shows that in the process of transmission the evolution of the light intensity is the same for different modulation depths and sizes of the defects.The deeper of the modulation depth of defects that modulated the beam,the higher of the intensity produced along the propagation process.The larger of the defect,the nearer of the proposition where produced the highest intensity from the defects location.The angular spectrum in the low frequency area become smaller and the angular spectrum in the high frequency area become greater with the increase of modulation depth and the size of the defect as well as the defect getting closer to the middle of the beam.