百千赫兹皮秒再生放大器的输出特性

Output Characteristics of Few Hundreds kHz Picosecond Regenerative Amplifiers

高重复频率再生放大器的能量提取周期远小于激光增益介质上能级寿命,这会导致再生放大器输出一高一低两种能量的激光脉冲,即倍周期分叉现象。针对上述问题,从理论上分析高重复频率Nd…YVO_4再生放大器的输出脉冲稳定性与重复频率之间的关系,发现提高再生放大器重复频率可以避免出现倍周期分叉现象,并通过实验验证了当重复频率大于250kHz时,Nd…YVO_4再生放大器没有出现倍周期分叉现象。此外,在吸收抽运功率为70 W时,实现了对单脉冲能量为1nJ、重复频率为94MHz的全固态Nd…YVO_4晶体半导体可饱和吸收镜锁模种子激光脉冲的再生放大,得到重复频率可调(250~500kHz)的皮秒激光,其最大输出功率达到18 W,单脉冲能量为36μJ。

Considering that the energy extraction period becomes much smaller than the energy upper state lifetime of the laser gain media, the output laser of high repetition rate regenerative amplifiers contains two-different-energy pulses, which is generally described as the period doubling bifurcation phenomenon. In order to solve this problem, we study the relation between the output laser pulse stabilization of high repetition rate regenerative amplifiers and repetition rate theoretically, and find that the period doubling bifurcation phenomenon can be avoided by increasing the repetition rate of regenerative amplifiers. The experimental results show the period doubling bifurcation phenomenon is avoided when the repetition rate is more than 250 kHz. Furthermore, the regenerative amplification of 1 nJ pulse enenrgy is produced by all-solid-state Nd： YVO~ crystal semiconductor saturable absorber mirror mode-locked picosecond laser with the repetition rate of 94 MHz. And when the absorbed pump laser is 70 W, we get the frequency tunable （250-500 kHz） picosecond laser. The maximum output average power is 18 W, and the single pulse energy is 36 μJ.