Tunable Near-Infrared Laser Emission at 1.7 μm Generated by Stimulated Raman Scattering of Sulfur Hexafluoride Molecules in Anti-Resonant Hollow-Core Fibers

Fiber lasers operating at 1.7 μm have significant application value in fields such as gas detection and material processing due to their characteristics, including compact structure and ease of thermal management. Based on the stimulated Raman scattering (SRS) of gas molecules in hollow-core fibers (HCFs), fiber gas Raman lasers (FGRLs) are a novel and effective method for generating 1.7 μm fiber lasers. We report here, to the best of our knowledge, the first FGRL based on the anti-resonant hollow-core fiber (AR-HCF) filled with sulfur hexafluoride (SF6) molecules. A nanosecond pulsed fiber amplifier tunable from 1540 to 1560 nm was used to pump a 17.8-m-long AR-HCF filled with SF6 molecules. By virtue of the vibrational SRS of SF6 molecules, laser output in the range of 1748–1774 nm was achieved. At a gas pressure of 15 bar, a maximum average power output of ~3 W was obtained, corresponding to an optical-to-optical conversion efficiency of ~22%. The output linewidth of the Raman laser was measured to be approximately 2.1 GHz using a Fabry–Pérot (F-P) scanning interferometer. The research results enriched the methods for 1.7 μm fiber laser output.