啁啾参数对光束远场分布的影响

啁啾脉冲光束的远场特性对其具体应用具有重要意义。利用夫琅禾费衍射积分公式导出了啁啾脉冲高斯光束远场光强分布的解析式，并通过数值计算分析了啁啾参数对远场分布的影响。结果表明，脉冲光束的远场中心光强随着脉宽的减小而增大，其远场轴上功率谱随着脉宽的增大而减小，与普通脉冲高斯光束相比，脉宽的变化对于啁啾脉冲光束的影响更大。脉冲光束的中心光强也随着谱宽的增大而增大，但啁啾参数的变化不会对其产生影响。

Influence of Chirp Parameter on Far-Field Distribution of the Beam

The far-field characteristics of chirped pulsed beams is of great significance to its specific application. Based on the Fraunhofer diffraction integral formula, the analytical expression of the far-field intensity distribution of chirped pulsed Gaussian beams is derived, the influence of chirp parameter on far-field distribution is analyzed by numerical calculation. The investigation reveals, the centerline irradiance in the far field of pulsed beam increases with the decrement of pulse duration, the axial power spectra in the far field of pulsed beam decreases with the increment of pulse duration. A comparison of ordi- nary pulsed Gaussian beam has shown that the chirped pulsed beam is more sensitive to the change of pulse duration. The centerline irradiance in the far field of pulsed beam increases with the increment of spectral bandwidth, however, it is inde- pendent of the change of chirp parameter.