An all-optical switch based on plasmonic metal–insulator–metal (MIM) waveguides and the Mach–Zehnder (MZ) interferometer is designed. In order to realize an all-optical and active switch, a nonlinear material with intensity-dependent refractive index is introduced in one arm. Other than studying a typical MZ structure, we also investigate the asymmetric case where unequal thicknesses and distances for MZ arms are proposed. The finite element method (FEM) with a refined triangle mesh is employed for simulations. Results for ON and OFF states are provided with or without employing the pump field. Investigation of the geometrical dispersion reveals tunability of the structure for specific frequencies in the terahertz region. Finally, we show that introducing asymmetric arms provides better tunability in the designed ultrafast nano-scale switch and suggests its potential applications in integrated optical circuits.

中文翻译：

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等离子增强干涉仪中超快纳米级光学开关

设计了一种基于等离子金属-绝缘体-金属（MIM）波导和马赫-曾德尔（MZ）干涉仪的全光开关。为了实现全光有源开关，将一根强度依赖于折射率的非线性材料引入一只臂中。除了研究典型的MZ结构之外，我们还研究了非对称情况，其中提出了MZ臂的厚度和距离不相等的情况。模拟采用了带有精制三角形网格的有限元方法（FEM）。无论是否使用泵场，都将提供ON和OFF状态的结果。对几何色散的研究揭示了太赫兹区域中特定频率的结构可调性。最后，