A plasmonic chiral structure, which is a nanostructure composed of noble metals that lacks planar symmetry, demonstrates significant potential for various applications in bio-sensing, optical forces, switching and controlling the photoluminescence, and detecting chiral light. Understanding its fundamental property of circular dichroism (CD) is critical for these applications. Although the surface plasmon resonance (SPR) mode at a specific moment can explain the CD properties of chiral structures, to gain a better understanding of chirality, the mode shape of the SPR on a nanostructure must be analyzed throughout an entire period. Our study proposes an X-shaped nanostructure to investigate the temporal evolution of plasmon resonance in chiral structures. The simulation results demonstrated that our structure exhibited a significant temporal evolution in plasmonic oscillations, providing new insights into the nature of chirality. In addition, we provided a comprehensive theoretical explanation of CD using the Born–Kuhn model. Furthermore, we discovered that the CD in the X-shaped structure was intensified by the asymmetric interference between the structure and underlying gold film substrate.

中文翻译：

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通过不对称表面等离子体干涉增强X形纳米结构的圆二色性

等离子体手性结构是一种由缺乏平面对称性的贵金属组成的纳米结构，在生物传感、光力、光致发光的切换和控制以及检测手性光等各种应用中表现出巨大的潜力。了解其圆二色性 (CD) 的基本特性对于这些应用至关重要。虽然特定时刻的表面等离子体共振（SPR）模式可以解释手性结构的CD特性，但为了更好地理解手性，必须在整个周期内分析纳米结构上SPR的模式形状。我们的研究提出了一种 X 形纳米结构来研究手性结构中等离子体共振的时间演化。模拟结果表明，我们的结构在等离子体振荡中表现出显着的时间演化，为手性本质提供了新的见解。此外，我们使用 Born-Kuhn 模型对 CD 进行了全面的理论解释。此外，我们发现X形结构中的CD由于结构和下面的金膜基底之间的不对称干涉而增强。