LAUSR

Since the invention of graphene, two-dimensional (2D) materials have attracted great interest in both fundamental science and potential applications. Here, we report the saturable absorption features of 2D (multilayered structure) molybdenum disulfide (MoS2) in the mid-infrared (mid-IR) wavelength region, and use it to passively Q-switch an Er3+-doped ZBLAN fiber laser at 2.8 µm. This MoS2 saturable absorber has a moderate modulation depth of 5% at 2.8 µm, making it an appropriate candidate for light modulating in the mid-IR spectral range. In stable Q-switching, the Er3+-doped ZBLAN fiber laser is widely tuned in both repetition rate and pulse width. Through increasing pump power, the repetition rate and pulse duration are monotonically tuned from 36 to 70 kHz and from 1.84 µs to 806 ns, respectively. The maximum average power is 140 mW (at 70 kHz), giving a pulse energy of 2 µJ and peak power of ~2.48 W. Successful Q-switching operation of this 2.8 µm fiber laser confirms that 2D MoS2 has great potentials as efficient light modulating elements in mid-IR regions.