Continuous harmonic mode-locked pulsed ultrafast fiber laser based on PtS2 saturable absorber

Saturable absorbers (SAs) play an important role in mode-locked fiber lasers. The search for SAs with excellent modulation properties has become a hot topic in the field of ultrafast photonics. PtS₂ is a ideal material for SA due to its suitable band gap and Easily peelable layer structure. We prepared PtS₂-SA by liquid-phase exfoliation (LPE) and tapered fiber. Subsequently, we measured the modulation depth of the prepared SA using the two-arm detection method as 6.4 %, and the saturation intensity is 4.5 MW/cm². By varying the input power in the annular cavity, a conventional solitons (CS) with a center wavelength is 1530.3 nm and a repetition frequency of 6.1 MHz was obtained. Continuing to increase the power, a stable second-fourth orders harmonic mode-locked (HML) was obtained. Our work shows that PtS₂-SA has excellent modulation in mode-locked fiber lasers. It also proves that PtS₂ has good saturable absorption properties and improves the knowledge of research workers about the performance of PtS₂. There is hope in future research work to further exploit the output properties of PtS_2.