Antennas Group-TERALAB, Universidad Pública de Navarra, Campus Arrosadía, 31006 Pamplona, Spain.
Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk Branch "TDIAM", Lavrentiev Ave. 2/1, 630090 Novosibirsk, Russia.
Sensors (Basel). 2018 Nov 9;18(11):3848. doi: 10.3390/s18113848.
Subwavelength hole array (HA) metasurfaces support the so-called extraordinary optical transmission (EOT) resonance that has already been exploited for sensing. In this work, we demonstrate the superior performance of a different resonant regime of HA metasurfaces called anomalous EOT, by doing a thorough numerical and experimental study of its ability in thin-film label-free sensing applications in the terahertz (THz) band. A comprehensive analysis using both the regular and anomalous EOT resonances is done by depositing thin layers of dielectric analyte slabs of different thicknesses on the structures in different scenarios. We carry out a detailed comparison and demonstrate that the best sensing performance is achieved when the structure operates in the anomalous EOT resonance and the analyte is deposited on the non-patterned side of the metasurface, improving by a factor between 2 and 3 the results of the EOT resonance in any of the considered scenarios. This can be explained by the comparatively narrower linewidth of the anomalous EOT resonance. The results presented expand the reach of subwavelength HAs for sensing applications by considering the anomalous EOT regime that is usually overlooked in the literature.
亚波长孔阵列（HA）超表面支持所谓的非凡光传输（EOT）共振，该共振已被用于传感。在这项工作中，我们通过对其在太赫兹（THz）波段的薄膜无标记传感应用中的能力进行彻底的数值和实验研究，展示了 HA 超表面的另一种共振状态——异常 EOT 的卓越性能。通过在不同场景下将不同厚度的介质分析物薄片沉积在结构上来使用规则和异常 EOT 共振进行全面分析。我们进行了详细的比较，并证明了当结构处于异常 EOT 共振且分析物沉积在超表面的无图案侧时，可获得最佳的传感性能，在任何考虑的情况下，与 EOT 共振相比，结果提高了 2 到 3 倍。这可以通过异常 EOT 共振的相对较窄的线宽来解释。所提出的结果通过考虑通常在文献中被忽视的异常 EOT 模式，扩展了亚波长 HA 在传感应用中的应用范围。
