克尔介质表面缺陷对高斯-谢尔模型光束的调制

Modulation of defect on Kerr medium for the intensity properties of Gaussian-Schell-model beam

利用惠更斯-菲涅耳衍射积分公式,推导了高斯-谢尔模型光束经非线性克尔介质的表面缺陷调制后的交叉谱密度公式,研究了受调制高斯-谢尔光束的光强演化特性。数值模拟表明:缺陷也可导致部分相干光束在介质后表面产生一个极强点,缺陷越大,极强点越远离介质。非线性折射率为正值或负值的介质也分别使部分相干光束发生会聚或发散现象。空间相干长度越长以及附加相移和缺陷尺寸越大,光场受调制越厉害。

Using Huygens-Fresnel diffraction integral formula,the expression for the cross-spectral density of the GaussianSchell model （GSM） beam which is modulated by the defect of the nonlinear Kerr medium surface is derived.The intensity distribution of GSM beam through the thin Kerr medium is studied.Numerical simulation shows that defect leads to the emergence of extreme intensity point near the rear of the nonlinear medium,which is more far away from the medium when the size of defect is increased.The partially coherent beam can also converge or diverge after passing through the medium with positive or negative nonlinear refractive index.A longer spatial coherence length,and a greater additional phase shift in the medium or a bigger size of defect,will lead to a more serious modulation for the light intensity.