2 µm Tm:YAP passively mode-locked laser based on WSSe and MoSSe saturable absorbers

This research examined the differential utilization of two transition metal dichalcogenide materials, WSSe and MoSSe, as saturable absorbers (SAs) in passively mode-locked (PML) laser systems. Few-layer nanosheets of both compounds were synthesized through liquid-phase exfoliation and employed as modulation elements within a 2.07 m cavity PML laser incorporating a Tm:YAP crystal as the gain medium. Ultrashort pulses of 867.5 and 957.3 ps were ultimately obtained in the laser under the modulation of WSSe-SA and MoSSe-SA. The minor variation in modulation performance is ascribed to the comparable nonlinear optical properties of the two materials. The I-scanning characterization revealed modulation depths and saturation intensities of 12.15% and 47.16kW/cm 2 for WSSe-SA, and 12.46% and 53.45kW/cm 2 for MoSSe-SA, indicating closely aligned parameters. Beyond pulse duration, the PML lasers utilizing these saturable absorbers achieved substantial average output powers of 492 and 546 mW, respectively. These findings substantiate the efficacy of WSSe and MoSSe as nonlinear optical materials, underscoring their significant potential for advancement in ultrafast photonics applications.