超短脉冲经线性小孔阵列衍射时的光谱开关特性

Spectral switches of Gaussian pulsed beam passing through linear circular apertures array

研究了超短高斯脉冲光束经线性排列的矩形光阑阵列衍射后的远场光谱奇变现象。基于菲涅耳积分公式,通过将光阑函数展开为有限项复高斯函数的叠加,得到了超短脉冲光束经线性排列的小孔光阑阵列衍射后的谱强度解析表达式,并对衍射场的光谱红移和蓝移现象进行了数值计算和分析,分析了小孔间距和光阑半径对光谱强度的影响。研究表明:在衍射场的某些观测点,即在调制函数为零的位置附近,存在光谱开关现象。

The far-field anomalous spectral behaviors of a Gaussian pulsed beam passing through a linear circular apertures array are studied.By expanding a hard aperture function into a finite sum of complex Gaussian functions and starting from the Fresnel diffraction integral,the approximate analytical expression for the spectral intensity of a space-time-dependent Gaussian pulsed beam passing through a linear circular apertures array is derived.The red and blue shifts and the spectral intensity distribution are studied and illustrated with numerical calculations.It is shown that there exist spectral switches when the observation position is at the right points.