In this research, the nonlinear optical properties of Ni nano-films were investigated in the cw regime. Metallic films with thicknesses of 4, 8 and 16 nm were fabricated at room temperature by thermal evaporation. The film's nonlinear optical properties were determined using the z-scan technique pumped at 650 nm. The films showed saturable absorber behavior which became stronger with the film's thickness. However, this behavior was not observed when the films were irradiated at 405 nm. A model based on the allowed density of states in the fabricated films is adopted to explain the dependence of the saturable absorber on the irradiation wavelength. Through the mechanistic discernments of the model, capability of controlling nonlinear optical limiting by light is discussed.

在这项研究中，Ni 纳米薄膜的非线性光学特性在 cw 范围内进行了研究。通过热蒸发在室温下制造厚度为 4、8 和 16 nm 的金属薄膜。使用在 650 nm 泵浦的 z 扫描技术确定薄膜的非线性光学特性。薄膜表现出可饱和的吸收剂行为，随着薄膜厚度的增加而变得更强。然而，当薄膜在 405 nm 下辐照时没有观察到这种行为。采用基于所制造薄膜中允许态密度的模型来解释可饱和吸收体对辐照波长的依赖性。通过模型的机理识别，讨论了控制非线性光限幅的能力。