无光栅频率分辨光学开关行迹分析

Effects of spatial beam profile on GRENOUILLE trace

从无光栅频率分辨光学开关(GRENOUILLE)的测量原理出发,分析了不均匀的光束空间轮廓导致行迹畸变的原因,并通过数值方法模拟了GRENOUILLE内部存在的数据一致性校验机制对这种影响的抑制作用。结果表明:不均匀光束空间轮廓对GRENOUILLE测量结果的影响并不显著;实际测量中更应避免的是使用过小的光束口径,它将导致行迹不完整,从而显著影响时间波形的测量结果。

In grading-eliminated no-nonsense observation of ultrafast incident laser light e-fields（GRENOUILLE） measurements of femtosecond laser pulse, a nonuniform spatial beam profile can largely distort the trace, which results in an inaccurate temporal measurement. The spatial beam profile effects on the GRENOUILLE trace are demonstrated both theoretically and numerically. Results from the numerical simulation show that due to the presence of feedback regarding the validity of the measurement data, the GRENOUILLE phase-retrieval algorithm is insensitive to trace distortion; hence a nonuniform spatial beam profile can hardly introduce any noticeable inaccuracy. Special attention should be paid to the situation where incident beam is too narrow to generate adequate delay between two replicas of the pulse, which leads to a clipped trace followed by a misleading temporal result.