Li Hao, Pei Wenxi, Li Xuanxi, Lei Luohao, Shi Jing, Zhou Zhiyue, Wang Zefeng
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China.
Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China.
Nanomaterials (Basel). 2024 Apr 11;14(8):661. doi: 10.3390/nano14080661.
Hollow-core photonic crystal fibers (HC-PCFs) provide an ideal transmission medium and experimental platform for laser-matter interaction. Here, we report a cascaded all-fiber gas Raman laser based on deuterium (D)-filled HC-PCFs. D is sealed into a gas cavity formed by a 49 m-long HC-PCF and solid-core fibers, and two homemade fiber Bragg gratings (FBGs) with the Raman and pump wavelength, respectively, are further introduced. When pumped by a pulsed fiber amplifier at 1540 nm, the pure rotational stimulated Raman scattering of D occurs inside the cavity. The first-order Raman laser at 1645 nm can be obtained, realizing a maximum power of ~0.8 W. An all-fiber cascaded gas Raman laser oscillator is achieved by adding another 1645 nm high-reflectivity FBG at the output end of the cavity, reducing the peak power of the cascaded Raman threshold by 11.4%. The maximum cascaded Raman power of ~0.5 W is obtained when the pump source is at its maximum, and the corresponding conversion efficiency inside the cavity is 21.4%, which is 1.8 times that of the previous configuration. Moreover, the characteristics of the second-order Raman lasers at 1695 nm and 1730 nm are also studied thoroughly. This work provides a significant method for realizing all-fiber cascaded gas Raman lasers, which is beneficial for expanding the output wavelength of fiber gas lasers with a good stability and compactivity.
空心光子晶体光纤（HC-PCF）为激光与物质相互作用提供了理想的传输介质和实验平台。在此，我们报道一种基于充氘（D）的HC-PCF的级联全光纤气体拉曼激光器。氘被密封在由一根49米长的HC-PCF和实心光纤形成的气腔中，并且进一步引入了两个分别具有拉曼波长和泵浦波长的自制光纤布拉格光栅（FBG）。当由1540纳米的脉冲光纤放大器泵浦时，腔内发生氘的纯转动受激拉曼散射。可获得1645纳米的一阶拉曼激光器，实现了约0.8瓦的最大功率。通过在腔的输出端添加另一个1645纳米的高反射率FBG，实现了全光纤级联气体拉曼激光振荡器，将级联拉曼阈值的峰值功率降低了11.4%。当泵浦源处于最大功率时，获得了约0.5瓦的最大级联拉曼功率，腔内相应的转换效率为21.4%，是先前配置的1.8倍。此外，还深入研究了1695纳米和1730纳米二阶拉曼激光器的特性。这项工作为实现全光纤级联气体拉曼激光器提供了一种重要方法，有利于在良好的稳定性和紧凑性下扩展光纤气体激光器的输出波长。
