Mao Dong, Zhang Shengli, Wang Yadong, Gan Xuetao, Zhang Wending, Mei Ting, Wang Yonggang, Wang Yishan, Zeng Haibo, Zhao Jianlin
Opt Express. 2015 Oct 19;23(21):27509-19. doi: 10.1364/OE.23.027509.
Transition-metal dichalcogenides, such as tungsten disulfide (WS2) and molybdenium disulfide (MoS2), are highly anisotropic layered materials and have attracted growing interest from basic research to practical applications due to their exotic physical property that may complement graphene and other semiconductor materials. WS2 nanosheets are found to exhibit broadband nonlinear saturable absorption property, and saturable absorbers (SAs) are fabricated by depositing WS2 nanosheets on side-polished fibers. Attributing to the weak evanescent field and long interaction length, the WS2 nanosheets are not exposed to large optical intensity, which allows the SA to work at the high-power regime. The SAs are used to mode lock erbium- and ytterbium-doped fiber lasers with normal dispersion, producing trains of dissipative soliton at 1.55 and 1.06 µm respectively. Simulations show that the bandgap of WS2 nanosheets decreases from 1.18 to 0.02 and 0.65 eV by introducing W and S defects respectively, which may contribute to the broadband saturable absorption property of the WS2.
过渡金属二硫属化物，如二硫化钨（WS2）和二硫化钼（MoS2），是高度各向异性的层状材料，由于其独特的物理性质可补充石墨烯和其他半导体材料，已引起从基础研究到实际应用的越来越多的关注。发现WS2纳米片表现出宽带非线性饱和吸收特性，并且通过将WS2纳米片沉积在侧面抛光的光纤上来制造饱和吸收体（SA）。由于倏逝场较弱且相互作用长度较长，WS2纳米片不会受到大的光强度影响，这使得SA能够在高功率状态下工作。这些SA用于锁模具有正常色散的掺铒和掺镱光纤激光器，分别在1.55和1.06μm处产生耗散孤子序列。模拟表明，通过分别引入W和S缺陷，WS2纳米片的带隙从1.18减小到0.02和0.65eV，这可能有助于WS2的宽带饱和吸收特性。
