Material design and input field properties limit high-harmonic excitation efficiency of surface-plasmon polaritons (SPPs) in a nanoscopic device. We remedy these limitations by developing a concept for a plasmonic waveguide that exploits spatiotemporal control of a weak surface polaritonic field to create efficient four-wave mixing (FWM) and periodic phase singularities. Our configuration comprises four-level double $\Lambda$-type atomic medium ($4\Lambda$ As) doped in a lossless dielectric situated above a negative-index metamaterial (NIMM) layer. We report the coherent excitation and propagation of the multiple surface polaritonic shock waves (SWs) and establish the highly efficient frequency combs by surface polaritonic wave (SPW) breaking. Consequently, multiple FWM and periodic plasmonic phase singularity patterns generate through nonlinear self-defocusing control commensurate with the plasmonic noise within the atomic electromagnetically induced transparency (EIT) window. Our work introduces SW formation within the subwavelength scale and generates efficient nonlinear frequency conversion, thereby opening prospects for designing fast optical modulators and nonlinear plasmonic gates.

中文翻译：

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混合等离子体激元波导中通过弱表面极化波破坏引起的非线性频率转换

材料设计和输入场属性限制了纳米器件中表面等离子体激元（SPP）的高谐波激发效率。我们通过开发等离子体波导管的概念来弥补这些局限，该等离子体波导管利用时空控制弱表面极化场来创建有效的四波混合（FWM）和周期相位奇点。我们的配置包括四级双$ \ Lambda $型原子介质（$ 4 \ Lambda $As）掺杂在位于负折射率超材料（NIMM）层上方的无损电介质中。我们报告了多个表面极化激波（SWs）的相干激发和传播，并通过表面极化激波（SPW）破坏建立了高效的频率梳。因此，通过与原子电磁感应的透明性（EIT）窗口内的等离子体噪声相对应的非线性自散焦控制，会生成多个FWM和周期性等离子体相奇异性模式。我们的工作在亚波长范围内引入了SW的形成，并产生了有效的非线性频率转换，从而为设计快速光学调制器和非线性等离子体闸打开了前景。