Study on pulse characteristics of high-repetition-rate harmonic mode-locked laser utilizing PbSnS2 saturable absorber

Abstract

This study explores the potential of lead-tin sulfide (PbSnS2), a novel two-dimensional material, for optical applications. PbSnS2 has a narrow bandgap and excellent light absorption, yet research on the optical characterization of PbSnS2 is still in its infancy, especially in applying its saturable adsorption properties to ultrafast photonics. This work focuses on the pulse output characterization of a fiber laser based on the saturable absorber (SA) of PbSnS2. High-quality PbSnS2 nanosheets were prepared using liquid-phase exfoliation. SAs with high damage thresholds were obtained by depositing PbSnS2 nanosheets on microfiber using a laser-induced process and applying them to nonlinear processes in ultrafast photonics. We report mode-locked and harmonic mode-locked generation in both (Er-110)- and (Er-OFS)-doped fiber lasers by using the same PbSnS2 SA. To our knowledge, this is the first report of a PbSnS2-based fiber laser at 1.5-μm band. Our research demonstrates the significant potential and capability of PbSnS2-based saturable absorbers in achieving harmonic pulse operation with a high repetition frequency. This finding further advances the exploratory investigation of optoelectronic devices based on transition metal dichalcogenides.