Equivalent Circuit Models of a Bifunctional Optical Metasurface for Beam Splitting and Refractive Index Sensing
Equivalent Circuit Models of a Bifunctional Optical Metasurface for Beam Splitting and Refractive Index Sensing
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DOI：
10.1021/acsphotonics.3c00456
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发表时间：
2023-06
期刊：
影响因子：
7
通讯作者：
Liye Li;Lijun Ma;Hongshun Sun;Senyong Hu;Meizhang Wu;Zhimei Qi;Wengang Wu
中科院分区：
文献类型：
--
作者：
Liye Li;Lijun Ma;Hongshun Sun;Senyong Hu;Meizhang Wu;Zhimei Qi;Wengang Wu
超表面由于具有显著的光学参数调制能力，在微纳米光学领域引起了广泛的关注。然而，目前的数值模拟技术由于耗费大量的计算时间和内存，不能有效地满足超表面设计和分析的需求。此外，它们不能直接说明光学响应背后的物理机制。在此，我们提出并系统地演示了基于可见波段偏振复用的金属-介电-金属结构元原子双功能超表面的两个等效电路模型。在极化状态下，建立了等效电路模型，对相移进行了精确解释，拟合优度为0.931，得到了由异常反射现象引起的分束函数。多色光从34°到69°分裂产生光栅型高饱和结构色，其色域约为DCI-P3标准的170.07%。在共极化状态下，由于超表面对环境变化的高灵敏度，产生了适合于折射率传感功能的表面晶格共振。第二个等效电路模型模拟了线宽变窄和红移现象，灵敏度相对误差为7.00%。为了模拟瑞利异常的特性，我们在模型中引入了带窄带通滤波器和串联电容的支路。这两个模型进一步扩展了等效电路理论在光学中的应用，并为深入了解超表面的机制提供了重要途径。
Metasurfaces have attracted extensive attention in the micro/nano-optics field depending on their significant ability to modulate optical parameters. However, the current numerical simulation technology cannot meet the demand of the design and analysis of metasurfaces efficiently due to consuming substantial calculating time and memory. Besides, they cannot illustrate the physical mechanism straightforwardly behind the optical responses. Herein, we propose and demonstrate two equivalent circuit models systematically for a bifunctional metasurface with metal–dielectric–metal structural meta-atoms based on polarization multiplexing in the visible band. In they-polarization state, the equivalent circuit model is established to interpret the phase shift exactly with a high goodness of fit of 0.931, resulting in the beam splitting function from the anomalous reflection phenomenon. The polychromatic light splits from 34 to 69° to produce the grating-type high-saturation structural colors with a large gamut of about 170.07% of the DCI-P3 standard. In thex-polarization state, the metasurface produces the surface lattice resonance that is suitable for the refractive index sensing function due to the high sensitivity to environmental changes. The second equivalent circuit model simulates the linewidth narrowing and red-shift phenomenon with a sensitivity relative error of 7.00%. We introduce a branch with a narrow-band-pass filter and a capacitor in series into the model to mimic the characteristic of Rayleigh anomalies. Both models extend the application of equivalent circuit theory in optics further and provide a crucial approach to enhance the insights into the mechanism of metasurfaces.