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 . PtS 2 is a ideal material for SA due to its suitable band gap and Easily peelable layer structure. We prepared PtS 2 -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/cm 2 . 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 PtS 2 -SA has excellent modulation in mode-locked fiber lasers. It also proves that PtS 2 has good saturable absorption properties and improves the knowledge of research workers about the performance of PtS 2 . There is hope in future research work to further exploit the output properties of PtS 2. • By performing characterization analyses, we demonstrate that PtS 2 have a distinct laminar structure. • The saturable absorber based on PtS 2 has a saturable absorption intensity of 4.5 MW/cm 2 and a modulation depth of 6.4 %. • Fundamental frequency-locked with a pulse width of 942 fs and 2nd-4th order continuous harmonic mode locking were realized • The experimentally obtained CS and 2nd-4th order continuous HML have high time and power stability. • We demonstrate that the 2D transition metal dichalcogenides PtS 2 has excellent saturable absorption properties.