【摘要】 本文采用共线和非共线两种大动态范围扫描三阶相关技术测量飞秒激光脉冲,并对其测量结果及其特征进行了理论和实验分析。实验发现,共线式扫描三阶相关方法由于存在基频光在空气中通过三倍频过程直接产生三次谐波的现象,导致实际能够测量的动态范围下降;而非共线式扫描三阶相关技术虽然对脉冲强度具有较高的动态测量范围,但非共线夹角和光斑的大小对测量脉冲宽度有很大的影响。理论计算和实验结果表明,非共线情况下,入射到和频晶体上的光束夹角和光斑直径越大,测量得到的脉冲宽度也越大。共线和非共线两种方式均不影响对次脉冲位置的判断,但由于非共线式三阶相关测量得到的脉冲宽度增加,主脉冲附近的小脉冲结构或者距离较近的两个脉冲将会难以分辨。更多还原

【Abstract】 Measurement results of femtosecond laser pulses with the home-made collinear and non-collinear, large dynamic range, scanning third-order correlation technique are analyzed theoretically and experimentally. It is found that the dynamic range is low for the collinear scanning third-order correlation method because of the direct third harmonic generation of the fundamental light in air. While the non-collinear measurement does not have this problem and thus has a higher dynamic range, the non-collinear angle and spot size have a significant influence on the measured pulse duration. In particular, both theoretical simulation and experimental results show that the measured pulse duration increases with the beam angle and spot size in this latter case. Although both noncollinearand collinear approaches can help locate the weak satellite pulses, due to the artificial pulse broadening introduced in the non-collinear scheme, it will be difficult for using this method to resolve or distinguish the detailed structures around the main pulse or any closely located neighboring pulses.更多还原