适用于亚10 fs的共心衍射无像差展宽器

在升级5TW/40fs钛宝石激光系统的过程中,伴随10fs种子源的使用,提出并研制了一种新型的共心衍射无像差展宽器和全能量压缩器。该展宽器的最大特点是通过平面镜反射使光束入射时所形成的衍射点与展宽后的还原点均在凹面镜的球心(即共心结构),凹面镜不存在其它同类方法中的成像问题,展宽函数中不涉及凹面镜的焦距和离轴量。该展宽器可将亚10fs的种子脉冲展宽到纳秒量级,且具有无像差、高带宽、结构紧凑、调整精度高等优点,适合100TW级超快激光系统中脉冲展宽。

Aberration-Free Stretcher Based on Concentric Diffraction for Sub-10fs Pulses

In the process of updating 5 TW/40 fs table-top Ti:sapphire laser system,a 10 fs pulse source is introduced,and a new type aberration-free pulse stretcher and compressor is proposed and designed.Compared with other stretchers,the specialty of the proposed one is that the diffraction point of input pulses and reverting point of stretched pulses coincide in the centre of the concave mirror,i.e.concentric structure.Imaging problems related to other methods don't appear in the concave mirror,and the focal length and adaxial approximation of the concave mirror are not involved in the stretching function.This stretcher system,aberration-free,compact,easy to adjust precisely,provides broad bandwidth,permits the stretching of sub-10 fs seed pulse to nanosecond level,and is suitable for 100 TW ultrafast laser system.