高斯光束经表面有缺陷的厚非线性介质的传输特性

摘要

The defects unavoidably existing on the optical component will modulate the phase and the amplitude of the beam propagation in the system.Based on the Fresnel diffractiond and split-step Fourier method,the two-dimensional intensity distributions of the Gaussion beam propagation in the nonlinear medium and the free space are simulated.And the intensity distributions of the beam propagation in the medium and the free space are also studied in the case where there exist defects on the front surface of thick medium.It is shown that the thicker the medium and the lager the nonlinear index of refraction,the stronger the beam focus and the closer to the medium surface the focal position is.The defects on the medium surface will lead to a strong beam intensity near the rear surface of the medium. And the intensity generated by the phase modulated defects is stronger than by the amplitude modulated defects.%光学元件上存在的缺陷会对传输光束产生局域振幅和位相调制.基于衍射理论模型和分步傅里叶算法,模拟分析了高斯光束经过表面有缺陷的非线性介质的传输过程中于介质内及从介质出射后在自由空气的传输特性,并详细研究了在厚介质前表面有缺陷的情况下,介质中和自由空气中的光强分布演化规律.研究表明,介质厚度越长、介质的非线性折射率越大,光束整体聚焦越厉害,聚焦点离介质后表面越近.光束受调制点的位置离中心越近,光束分裂成丝产生的局部光强越大,且介质表面存在缺陷将使通过的光束在介质后表面处产生一个很大的光强,相位调制型缺陷产生的这一光强点比振幅调制型缺陷产生的光强点更强.