All-fiber structure tunable mid-infrared light source based on acetylene-filled hollow-core fibers

Utilizing unique waveguiding properties, hollow-core fibers (HCFs) provide an ideal platform for studying light-matter interactions, pioneering what we believe to be new research directions in the fields of laser technology, optical communications and biophotonics. Gas-filled hollow-core fiber gas lasers (HCFGLs) have garnered significant interest due to their rich emission wavelengths, high beam quality, and flexible beam delivery capabilities. However, most HCFGLs remain constrained by free-space coupling configurations, exhibiting high susceptibility to environmental variations. Here, we demonstrate an all-fiber acetylene-filled HCFGL based on fusion splicing technique. Through optimization of acetylene pressure within the HCFs, a maximum mid-infrared output power of 5.02 W is obtained with a slope efficiency of 17.3%. By adjusting the wavelength of the pump laser to align with different absorption lines of the gas precisely, a tunable laser output is achieved in the 3.1∼3.2 µm waveband. As far as we know, this is the first watt-level all-fiber tunable mid-infrared HCFGL. This work marks a notable advancement in all-fiber mid-infrared laser generation, opening a new avenue for the development of high-power tunable mid-infrared fiber laser sources.