Hafnium sulfide nanosheets for large energy passively Q-switched fiber laser application

We report the generation of 240 nJ, robust pulses at 1.5 μm by inserting the hafnium sulfide (HfS2) into the compact Er-doped fiber (EDF) laser. The multilayer HfS2 nanosheets prepared by liquid exfoliation was experimentally studied as a good performance saturable absorber (SA) with the modulation depth (ΔT) of 11.32%. The slope efficiency of fiber laser is as high as 8.9%. Compared with recent reported works, our experimental results show better comprehensive performance. This work demonstrates that HfS2 with prominent nonlinear saturable absorption property could be used as a promising candidate to advance the development of nonlinear optics.