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.