在啁啾脉冲放大飞秒激光系统中, 为了获得近傅里叶变换极限的超短飞秒脉冲输出, 需要对飞秒脉冲的光谱相位进行测量并消除未被补偿的残留啁啾。而光谱干涉仪因为其线性性、结构简单和灵敏度高等优点在飞秒脉冲光谱相位测量方面具有重要应用。介绍了基于交叉偏振波或自衍射效应的自参考光谱干涉技术, 详细论述了该技术的工作原理。特别地以高斯光谱入射脉冲为例, 对待测脉冲的光谱相位重构进行了详细的数值模拟, 并指出基于交叉偏振波及自衍射效应的自参考光谱干涉技术对线性啁啾的测量范围。最后简单介绍利用光谱干涉仪和声光可编程色散滤波器相结合, 用以消除飞秒激光脉冲中光谱相位残留啁啾的原理, 实验中通过2次反馈迭代就获得了近傅里叶变换极限的飞秒脉冲输出。

In order to obtain near Fourier transform limited (FTL) pulse in femtosecond laser system based on chirped pulse amplification (CPA) technique, it is necessary to measure the spectral phase and eliminate the residual chirp for the pulse. Spectral interferometry has great application in measuring the spectral phase of femtosecond pulse, because it′s advantage of linear, compact and high sensitivity. Self-referenced spectral interferometry (SRSI) based on cross-polarized wave (XPW) or self-diffraction wave (SDW) is introduced in detail. Especially, numerical simulation in reconstruction of the spectral phase has been carried on with a Gaussian shape input pulse, and the tolerable range of linear chirp for the measured pulse when using the SRSI has been discussed. Finally, the principle of pulse residual chirp elimination based on combination of SRSI and acousto-optic programmable dispersive filter (AOPDF) has been briefly introduced, and near FTL pulse has been obtained through two feedback iterations experimentally.