Ultrafast Fiber Laser Based on Tungsten Sulphoselenide Materials

Tungsten sulphoselenide (WSSe) alloys, belonging to the transition metal dichalcogenide family, have attracted significant interest in the area of optoelectronics because of their unique optical and electronic properties. However, there has been a dearth of sufficient research on the saturable absorption features and ultrafast lasers applications. Herein, we fabricated a WSSe-microfiber saturable absorber (SA) based on WSSe nanosheets prepared by liquid exfoliation technique. The SA provided a saturation intensity of a modulation depth of 27.95% and a nonsaturable loss of 21.34%. To investigate the potential applications of WSSe in ultrafast photonics, the prepared WSSe-microfiber was incorporated into an Er-doped fiber laser ring cavity. The results demonstrated that the WSSe-based SA successfully generated mode-locking laser pulses with a remarkably short pulse width of 231 fs. Furthermore, the output power of this ultrafast fiber laser reached an impressive value of 15.68 mW. These findings provide valuable views into the unique features of WSSe alloys in the areas of ultrafast optics and develop recipes for SA in ultrafast fiber lasers.