论文标题
Epsilon-Near-Zero材料中的可逆光学非线性
Invertible Optical Nonlinearity in Epsilon-near-zero Materials
论文作者
论文摘要
Epsilon-near-Zero（ENZ）材料（例如含氧氧化物（ITO））最近成为增强光学非线性的新平台。在这里，我们报告了一项关于ITO薄膜非线性起源的理论和实验研究，该研究由基于内标和带间跃迁的两种机制主导。我们表明，有两个竞争因素共同导致ITO在其ENZ区域附近的频谱不可线性非线性，即带状结构的非副代谢性，从而导致内媒体过渡和费米能量转移的有效质量更大，从而决定了自由载体密度。我们的工作揭示了ITO膜的大型非线性与内在材料特性之间的关系。
Epsilon-near-zero (ENZ) materials such as indium tin oxide (ITO), have recently emerged as a new platform to enhance optical nonlinearities. Here we report a theoretical and experimental study on the origin of nonlinearities in ITO thin films that are dominated by two mechanisms based on intraband and interband transitions. We show that there are two competing factors that jointly contribute to a spectrally-invertible nonlinearity of ITO near its ENZ region i.e. the non-parabolicity of the band structure that results in a larger effective mass in the intraband transition and the Fermi energy shift, which determines the free carrier density. Our work reveals the relationship between the large nonlinearity and the intrinsic material properties of the ITO films.
