自相关法测量飞秒激光双脉冲若干参量的研究

Femtosecond Laser Double Pulse Autocorrelation Measurements and Research of Fitting Method

飞秒激光双脉冲在研究光泵浦的超快瞬态过程领域具有重要的应用价值,如何实现高准确度的飞秒激光双脉冲的实时测量显得尤为重要.本文提出了一种基于自相关法的飞秒激光双脉冲参量的测量方法,可实现对共光路传输、具有飞秒至皮秒级时间间隔的飞秒激光双脉冲的脉冲间隔、脉冲宽度和强度比的实时测量.实验中采用自相关仪测得了双折射晶体(钒酸钇)分束出的飞秒激光双脉冲的自相关曲线,并用非线性拟合算法求得了飞秒激光双脉冲的脉冲间隔、脉冲宽度和强度比参量.实验结果表明,本文方法与互相关测量方法相比,克服了参考脉冲参量的不确定性对检测准确度的影响,使测量平均准确度提高了48%以上.

Femtosecond laser double-pulse has important application value on the study of ultra-fast transient process area. How to realize the high accuracy of femtosecond laser pulse real-time measurement is particularly important.This paper presents a method on autocorrelation of femtosecond laser double-pulse measurement.It contains the measurement techniques of pulse interval,pulse width and the intensity ratio.Autocorrelator was used in the experiment to get the autocorrelation curve of the femtosecond laser double-pulse.The femtosecond laser double-pulse were generated by the birefringent crystal.Relying on the autocorrelation curve,the pulse interval,pulse width and the intensity ratio were got by non-linear fitting method. Contrasted the traditional cross-correlation measurement,the autocorrelation method overcome the uncertainty of the independent pulse impact on accuracy.It makes the measuring precision could be improved by more than 48% on average.