In this Letter, we demonstrate a high pulse energy and linearly polarized mid-infrared Raman fiber laser targeting the strongest absorption line of ${\rm CO}_2$ at $\sim{4.2}\;\unicode {x00B5} {\rm m}$. This laser was generated from a hydrogen (${\rm H}_2$)-filled antiresonant hollow-core fiber, pumped by a custom-made 1532.8 nm Er-doped fiber laser delivering 6.9 ns pulses and 11.6 kW peak power. A quantum efficiency as high as 74% was achieved, to yield 17.6 µJ pulse energy at 4.22 µm. Less than 20 bar ${\rm H}_2$ pressure was required to maximize the pulse energy since the transient Raman regime was efficiently suppressed by the long pump pulses.

中文翻译：

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高脉冲能量和量子效率的中红外气体拉曼光纤激光器的目标是吸收4.2 µm的CO ₂

在这封信中，我们演示了以$ \ sim {4.2} \; \ unicode {x00B5} {\ rm为目标，最强吸收线为$ {\ rm CO} _2 $的高脉冲能量和线性偏振的中红外拉曼光纤激光器m} $。该激光器由填充有氢（$ {\ rm H} _2 $）的反谐振空心光纤产生，并由定制的1532.8 nm掺Er光纤激光器泵浦，提供6.9 ns脉冲和11.6 kW峰值功率。量子效率高达74％，在4.22 µm处产生17.6 µJ脉冲能量。为了使脉冲能量最大化，需要的压力小于20 bar $ {\ rm H} _2 $，这是因为长泵脉冲有效地抑制了瞬态拉曼状态。