Metamaterials are artificial materials made of subwavelength elementary cells that give rise to unexpected wave properties that do not exist naturally. However, these properties are generally achieved due to 3D patterning, which is hardly feasible at short wavelengths in the visible and near-infrared regions targeted by most photonic applications. To overcome this limitation, metasurfaces, which are the 2D counterparts of metamaterials, have emerged as promising platforms that are compatible with planar nanotechnologies and thus mass production, which platforms the properties of a metamaterial into a 2D sheet. In the linear regime, wavefront manipulation for lensing, holography, and polarization control has been achieved recently. Interest in metasurfaces operating in the nonlinear regime has also increased due to the ability of metasurfaces to efficiently convert incident light into harmonic frequencies with unusual polarization properties. However, to date, the nonlinear absorption of metasurfaces has been mostly ignored. Here, we demonstrate that plasmonic metasurfaces behave as saturable absorbers with modulation performances superior to the modulation performance of other 2D materials and exhibit unusual polarimetric nonlinear transfer functions. We quantify the link between saturable absorption, the plasmonic resonances of the unit cell and their distribution in a 2D metasurface, and finally provide a practical implementation by integrating the metasurfaces into a fiber laser cavity operating in pulsed regimes driven by the metasurface properties. As such, this work provides new perspectives on ultrathin nonlinear saturable absorbers for applications where tunable nonlinear transfer functions are needed, such as in ultrafast lasers or neuromorphic circuits.

超材料是由亚波长基本单元制成的人造材料，这些材料会引起自然界不存在的意外波特性。但是，这些属性通常是通过3D图案实现的，在大多数光子应用所针对的可见光和近红外区域中，在短波长下这几乎是不可行的。为了克服这一限制，作为超材料的2D对应物的超表面已经成为有前途的平台，可与平面纳米技术兼容，从而可大规模生产，从而将超材料的特性平台化为2D薄板。在线性状态下，近来已经实现了用于透镜，全息和偏振控制的波前操纵。由于超表面能够有效地将入射光转换为具有异常偏振特性的谐波频率，因此人们对以非线性方式运行的超表面的兴趣也有所增加。然而，迄今为止，超表面的非线性吸收已被忽略。在这里，我们证明等离子超表面表现为可饱和的吸收体，其调制性能优于其他2D材料的调制性能，并表现出不寻常的极化非线性传递函数。我们量化了饱和吸收，晶胞的等离子共振及其在二维超颖表面中的分布之间的联系，最后通过将超颖表面集成到由超颖表面特性驱动的脉冲状态下工作的光纤激光腔中，提供了一种实际的实现方法。因此，