Two-dimensional materials have attracted increasing attention because of their excellent mechanical, thermodynamic, magnetic, electrical and optical properties. Here, a new two-dimensional material of tin sulfide (SnS) is experimentally prepared. It is layered like black phosphorus and owns distinct optoelectronic properties, but eliminates the disadvantage of instability. The nonlinear saturable absorption characteristics of the SnS nanosheets is investigated at 1563.3 nm by the double-balanced detection method. The obtained modulation depth and saturation intensity are 5.4% and 66.3 MW/cm2, respectively. A passively harmonic mode-locked erbium-doped fiber laser based on the SnS saturable absorber (SA) has been demonstrated. The results show that mode-locking with fundamental frequency of 5.47 MHz is realized at pump power of 28.38 mW. With the increase of pump power, the laser can operate from fundamental frequency to high-order harmonic mode-locking. The maximum repetition rate of 412.73 MHz has been obtained, which is equivalent to the 76th harmonic mode-locking. This work reveals that SnS nanosheets is a novel and efficient SA with high damage threshold, which will find potential applications in optical communication, photoelectric detection, laser medicine, etc.

中文翻译：

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用于在近红外区域产生谐波脉冲的 SnS 纳米片

二维材料因其优异的机械、热力学、磁、电和光学性能而受到越来越多的关注。在这里，通过实验制备了一种新型二维硫化锡（SnS）材料。它像黑磷一样分层，具有独特的光电特性，但消除了不稳定的缺点。通过双平衡检测方法研究了 SnS 纳米片在 1563.3 nm 处的非线性可饱和吸收特性。获得的调制深度和饱和强度分别为 5.4% 和 66.3 MW/cm2。一种基于 SnS 可饱和吸收体 (SA) 的被动谐波锁模掺铒光纤激光器已被证明。结果表明，在28.38 mW的泵浦功率下实现了基频为5.47 MHz的锁模。随着泵浦功率的增加，激光器可以从基频工作到高次谐波锁模。获得了412.73 MHz的最大重复率，相当于76次谐波锁模。这项工作表明，SnS 纳米片是一种新型高效的具有高损伤阈值的 SA，将在光通信、光电检测、激光医学等方面找到潜在的应用。