Papari Gian Paolo, Koral Can, Andreone Antonello
Department of Physics, University of Naples "Federico II", and CNR-SPIN, I-80125 Naples, Italy.
Istituto Nazionale di Fisica Nucleare (INFN), Naples Unit, Complesso Universitario di Monte S. Angelo, via Cinthia, I-80126 Naples, Italy.
Sensors (Basel). 2019 Jun 4;19(11):2544. doi: 10.3390/s19112544.
We describe an experimental strategy for the use of Terahertz (THz) metasurfaces as a platform for label-free wide range detection of the dielectric function in biological fluids. Specifically, we propose a metagrid (MG), opportunely infiltrated with a fluid and then capped, as the reference structure for sensing experiments with a high reproducibility character. By combining experiments and full-wave simulations of the transmission of such a structure, we introduce a reliable set up where the volume of the involved analyte in each unit cell is precisely determined. The unavoidable decrease in the quality factor of the intrinsic resonances due to the lossy fluid and cap layer is circumvented using an appropriate transformation of that amplifies the change in the MG intrinsic resonances, improving in such a way the sensor sensitivity to values close to the experimental limits. The transformed signal features delta-like peaks enabling an easy readout of frequency positions at resonances.
我们描述了一种实验策略，即使用太赫兹（THz）超表面作为平台，用于对生物流体中的介电函数进行无标记宽范围检测。具体而言，我们提出了一种元网格（MG），适当地用流体渗透然后覆盖，作为具有高重现性特征的传感实验的参考结构。通过结合这种结构传输的实验和全波模拟，我们引入了一种可靠的设置，其中每个单元胞中所涉及分析物的体积被精确确定。由于有损耗的流体和覆盖层导致的固有共振品质因数不可避免的下降，通过适当的变换得以规避，该变换放大了MG固有共振的变化，从而将传感器灵敏度提高到接近实验极限的值。变换后的信号特征呈现出类似δ的峰值，便于轻松读出共振时的频率位置。
