皮秒多脉冲泵浦KGW红外多波长拉曼激光器

报道了多脉冲机制泵浦KGW晶体的皮秒红外多波长拉曼激光器。建立数学模型研究了多脉冲泵浦机制对拉曼活性分子振动模式的影响，模拟结果显示了拉曼活性分子对多脉冲泵浦机制的响应相比于传统的单脉冲泵浦机制更加活跃与持久，从而促进衰减的分子振荡多次回到本征振动频率。多脉冲的增强效果有利于改善拉曼增益，降低拉曼阈值，提高拉曼转换效率。设计了皮秒多脉冲泵浦KGW拉曼晶体实验，结果表明，三脉冲泵浦机制将拉曼增益改善了2倍以上，拉曼阈值降低了50%以上，768 cm–1和901 cm–1拉曼模式的转换效率分别提高了16%和22%以上。基于三脉冲泵浦机制，设计了1 kHz毫焦级皮秒多脉冲泵浦KGW晶体红外多波长拉曼激光器，对于768 cm–1和901 cm–1两个振动模式，获得脉冲能量分别为1.39 mJ和1.38 mJ，最大拉曼转换效率分别为29.6%和25.7%。此外，对于两种拉曼模式，此拉曼激光器都可以同时输出多达8条红外拉曼光谱，涵盖范围800~1 700 nm。

Picosecond multi-pulse burst pump KGW infrared multi-wavelength Raman laser

Picosecond infrared multi-wavelength Raman laser which adopted multi-pulse pumped KGW crystal was reported. A mathematical model was developed to investigate the effect of multi-pulse burst pumping regime on the vibrational mode of the Raman active molecule. The simulated results show that the response oscillation of the Raman active molecule to the multi-pulse burst pumping regime is more active and durable compared with the traditional single pulse pumping regime, which promotes the weakened molecule oscillation to return the natural frequency multiple times. The enhancement effect is beneficial to improve the Raman gain, reduce the Raman threshold, and increase the Raman conversion efficiency. During the experiment of picosecond multi-pulse pump KGW Raman crystal, the three-pulse burst pumping regime improves the Raman gain more than two times, reduces the threshold of stimulated Raman scattering more than 50%, and increases the Raman conversion efficiency more than 16% for 768 cm–1 Raman mode and 22% for 901 cm–1 Raman mode. Based on the three-pulse burst pumping regime, a 1 kHz mJ-level picosecond infrared multi-wavelength Raman laser was designed, which achieved the pulse energy of 1.39 mJ, the maximum Raman conversion efficiency of 29.6% for the 768 cm–1 vibrational mode of KGW, and the pulse energy of 1.38 mJ, the maximum Raman conversion efficiency of 25.7% for the 901 cm–1 vibrational mode of KGW. In addition, the Raman laser can radiate up to eight infrared Raman lines simultaneously for both the two vibrational modes of the KGW crystal, which covers the range of 800–1 700 nm.