啁啾脉冲放大系统中单光栅展宽器的优化

Optimization of the Single-grating Stretcher in Chirped-pulse Amplification

计算了啁啾脉冲激光放大系统中单光栅展宽器在入射角大于和小于利特罗角两种入射情况 ,发现对同一飞秒脉冲在相同展宽比条件下 ,入射角小于利特罗角时所需光栅宽度要远小于入射角大于利特罗角时所需的光栅宽度 ,且在入射角小于利特罗角时存在一最佳入射角 ,此时所对应的光栅宽度达到最小值。同时理论分析及数值计算显示 ,在上述条件下入射角小于利特罗角时此单光栅展宽器的等效光栅对间距较入射角大于利特罗角时大为缩短。

For a pulse under the same stretch ratio there are two cases: one is the incident angle being less than Littrow angle and the other is the incident angle being bigger than Littrow angle. Investigation shows that the needed grating width is less in the former case than that in the latter case, and with the incident angle being one optimum value the needed grating width will reach the maximum in first case. Under the same condition the perpendicular distance between the gratings is also much less in first case than that in second case.