Ultrafast pulse generation based on the 2D analogue of black phosphorus—GeS

Abstract

In our works, germanium monosulfide (GeS) was employed as a saturable absorber for obtaining passively mode locked fiber laser. Unlike two-dimensional transition metal dichalcogenides, we report the nonlinear optical properties of GeS and its application as novel saturable absorbers in generating mode-locked lasers. At present, reports of this 2D material applied to ultrafast lasers are rare. By inserting a saturable absorber in the fiber laser cavity, we obtained pulse duration of 854 femtosecond and 560 picosecond laser pulse output in the erbium-doped fiber laser and the ytterbium-doped fiber laser, respectively. The experimental results display that GeS sheets have excellent saturable absorption properties, which open the new avenue for group IV monosulfide to laser photonic devices and will have a wide range of potential applications in the field of ultrafast photonics.