Li Chun, Teng Yan, Xiao Yuhua, Su Runfeng, Yu Mei, Juan Yue, Hua Min, He Jingjing, Jiang Ling
Appl Opt. 2022 Nov 10;61(32):9398-9404. doi: 10.1364/AO.471139.
We experimentally present a tunable electromagnetically induced transparency (EIT)-like response in bright-bright mode resonators. In contrast to previous studies, we used NbN film and a gold film composite structure metamaterial. A significant slow-light effect could be observed at the transmission window, and the maximum group index could reach 100. As a variation in temperature alters the intrinsic ohmic loss of superconducting NbN film, a temperature-dependent transmittance and slow-light effect were observed. To better illustrate the physical mechanism of the two modes, a hybrid coupling model was introduced to fit the experimental transmission spectra and extract the characteristic parameters of sub-resonators. We found excellent agreement with experimental results. Our results provide deeper insight into the metamaterial analogs of an EIT-like response and offer an alternative approach for engineering slow-light devices, bandpass filters, and switches/modulators at terahertz frequencies.
我们通过实验展示了亮-亮模式谐振器中类似可调谐电磁诱导透明（EIT）的响应。与之前的研究不同，我们使用了氮化铌薄膜和金薄膜复合结构超材料。在传输窗口处可观察到显著的慢光效应，最大群折射率可达100。由于温度变化会改变超导氮化铌薄膜的固有欧姆损耗，因此观察到了与温度相关的透射率和慢光效应。为了更好地说明这两种模式的物理机制，引入了一种混合耦合模型来拟合实验透射光谱并提取子谐振器的特征参数。我们发现与实验结果非常吻合。我们的结果为深入了解类似EIT响应的超材料提供了见解，并为太赫兹频率下的慢光器件、带通滤波器以及开关/调制器的工程设计提供了一种替代方法。
