可用于超精细加工的高重复率、高光束质量飞秒再生放大脉冲的产生研究

Generation of high repetition rate femtosecond Ti:sapphire regenerative amplified pulse of high beam quality for ultra-precision machining

通过飞秒放大增益饱和理论及飞秒脉冲展宽的理论计算与分析 ,指出在优化放大腔结构参数及改变抽运光能量情况下 ,可以在省略展宽器基础上实现中等能量的飞秒脉冲再生放大 .以此为依据 ,采用低抽运能量和放大腔中钛宝石晶体离焦技术 ,成功地进行了无展宽器的高重复率飞秒钛宝石再生放大及压缩技术的实验研究 ,并获得了高光束质量的飞秒放大光脉冲 ,放大光脉冲能量大于 10 0 μJ,重复频率为 1kHz,光谱带宽 7.7nm ,压缩后脉宽 5 0 0fs.

On the basis of calculation and analysis on femtosecond amplification gain saturation and femtosecond pulse stretching, we believe it is possible to achieve moderate energy femtosecond regenerative amplification without stretcher if the amplifying cavity parameters is optimized and the pumping pulse energy is changed. According to the conclusion, applying low pumping energy and Ti:sapphire off-focusing technique to the amplifier, we do the experiment about high repetition rate femtosecond Ti:sapphire regenerative amplification and compressing without the stretcher. The femtosecond amplified pulse of perfect beam quality is obtained. The energy of amplified pulse is more than 100μJ.The amplified pulse repetition is 1kHz. The spectrum FWHM is 7 7nm.After the compressing,the pulsewidth is 500fs.