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/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 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 PtS2.