We report high-energy, high-efficiency second harmonic generation in a near-infrared all-solid-state burst-mode picosecond laser at a repetition rate of 1 kHz with four pulses per burst using a type-I noncritical phase-matching lithium triborate crystal. The pulses in each burst have the same time delay ( ${\sim}1~\text{ns}$ ), the same pulse duration ( ${\sim}100~\text{ps}$ ) and different relative amplitudes that can be adjusted separately. A mode-locked beam from a semiconductor saturable absorber mirror is pulse-stretched, split into seed pulses and injected into a Nd:YAG regenerative amplifier. After the beam is reshaped by aspheric lenses, a two-stage master oscillator power amplifier and 4f imaging systems are applied to obtain a high power of ${\sim}100~\text{W}$ . The 532 nm green laser has a maximum conversion efficiency of 68%, an average power of up to 50 W and a beam quality factor $M^{2}$ of 3.5.

中文翻译：

---

高效 50 W 突发模式百皮秒绿光激光器

我们报告了使用 I 型非临界相位匹配三硼酸锂在近红外全固态突发模式皮秒激光器中以 1 kHz 的重复频率产生高能、高效的二次谐波，每次突发四个脉冲水晶。每个突发中的脉冲具有相同的时间延迟（ ${\sim}1~\text{ns}$ ），相同的脉冲持续时间（ ${\sim}100~\text{ps}$ ) 以及可以单独调整的不同相对幅度。来自半导体可饱和吸收镜的锁模光束被脉冲拉伸，分成种子脉冲并注入 Nd:YAG 再生放大器。光束经过非球面透镜整形后，应用两级主振荡器功率放大器和4f成像系统获得高功率 ${\sim}100~\text{W}$ . 532nm绿光激光器最高转换效率68%，平均功率高达50W，光束品质因数 $M^{2}$ 3.5。