A cuprous oxide (Cu2O) thin film was prepared by radio-frequency (RF) magnetron sputtering. The crystal structure, linear transmission spectrum and film thickness were characterized by X-ray diffraction (XRD), ultraviolet–visible–near infrared (UV–Vis–NIR) absorption spectroscopy and ellipsometry. By performing the pump-probe and [Formula: see text]-scan technique, respectively, nondegenerate and degenerate two-photon absorption (D-TPA) coefficients of the Cu2O thin film at several different excitation wavelengths were experimentally determined. The nondegenerate two-photon absorption (ND-TPA) coefficient always exhibits larger magnitude than the corresponding D-TPA coefficient. In particular, the ND-TPA coefficient shows a maximum value of [Formula: see text][Formula: see text]cm/GW. This study indicates that the cuprous oxide could be a potential material for ultrafast nonlinear photonic devices based on two-photon absorption due to its large ND-TPA coefficient.

中文翻译：

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氧化亚铜薄膜中的非简并和简并双光子吸收

氧化亚铜（Cu2O) 薄膜是通过射频 (RF) 磁控溅射制备的。采用 X 射线衍射 (XRD)、紫外-可见-近红外 (UV-Vis-NIR) 吸收光谱和椭偏仪对晶体结构、线性透射光谱和薄膜厚度进行了表征。通过分别执行泵浦探针和 [公式：见文本] 扫描技术，Cu 的非简并和简并双光子吸收 (D-TPA) 系数2实验确定了几种不同激发波长的 O 薄膜。非简并双光子吸收 (ND-TPA) 系数始终表现出比相应的 D-TPA 系数更大的幅度。特别地，ND-TPA系数显示出最大值[公式：见正文][公式：见正文]cm/GW。该研究表明，由于其较大的 ND-TPA 系数，氧化亚铜可能成为基于双光子吸收的超快非线性光子器件的潜在材料。